A Phenotypic Atlas for Huntington Disease Based on Data From the Enroll-HD Cohort Study

Background and Objectives

The variable CAG repeat expansion in the huntingtin gene and its inverse relationship to motor dysfunction onset are fundamental features of Huntington disease (HD). However, the wider phenotype (including non-motor features) at particular CAG lengths, ages, and functional levels is less well-characterized. The large number of participants in the Enroll-HD observational study enables the development of a phenotype atlas that summarizes the range and distribution of HD phenotypes, including outliers and possible clusters, with respect to various CAG repeat lengths, age ranges, and declining functional levels.

Methods

Enroll-HD is an ongoing prospective longitudinal observational study that collects natural history data, releasing periodic data sets, in people with HD (PwHD) and controls. Core assessments at annual visits focus on behavioral, cognitive, motor, and functional status. Periodic data set 5, used for the development of the first iteration of the Enroll-HD Phenotype Atlas (EHDPA), included all eligible data collected through October 31, 2020. The atlas is based on subsets (cells) of descriptive data for all motor, cognitive, psychiatric, and functional measures that are routinely collected at most Enroll-HD sites, analyzed by single CAG lengths and 5-year age blocks.

Results

Data from 42,840 visits from 15,982 unique PwHD were available for analysis. At baseline, participants had a mean ± SD age of 48.9 ± 13.9 years and CAG repeat length of 43.4 ± 3.6 and 54.1% were female. The EHDPA includes 223 age-by-CAG subsets for CAG repeats between 36 and 69 with five-year age brackets starting from 20-24 years up to 85-89 years. The atlas can be browsed at enroll-hd.org/for-researchers/atlas-of-hd-phenotype/.

Discussion

The EHDPA summarizes the spectrum and distribution of HD phenotypes, including outliers and possible clusters, in all domains of disease involvement for the range of CAG repeat lengths, ages, and functional levels. Its availability in an easy-to-use online format will assist clinicians in tracking disease progression in PwHD by identifying phenotypic features most associated with loss of function and enabling conversations related to prognosis. The observable patterns in the EHDPA should also catalyze more formal multidomain characterization of motor, cognitive, and psychiatric progression and their relationships to functional decline and disease modifiers.

Trial Registration Information

Enroll-HD is registered with clinicaltrials.gov: NCT01574053.

Greater time in bed and less physical activity associate with poorer cognitive functioning performance in Huntington's disease

Objective: This study aimed to investigate how sleep and physical activity habits related to cognitive functioning, in naturalistic settings, in early Huntington's disease (HD). Method: Forty-two participants with the expanded HD repeat (20 manifest, 22 premanifest) and 29 healthy controls wore Fitbit One sleep and activity monitors for 7 days and 7 nights. They used a smartphone application to complete daily sleep and activity diaries, sleep and mood inventories, and a brief battery of cognitive tests, which were completed on Day 8 of the study. All data were collected in naturalistic home and community settings. Results: Amongst participants with the expanded HD repeat, greater time spent in bed, measured by Fitbit, was associated with poorer accuracy and response speed on a test of visual memory, whereas lower levels of physical activity, measured by Fitbit, were associated with poorer accuracy on a test involving a working memory component. Neither time in bed nor physical activity is associated with a test of psychomotor speed. Groups were mostly similar across a range of Fitbit and self-report measures of sleep and physical activity, although the Manifest-HD group spent more time in bed than the Premanifest-HD and Healthy Control groups and had better self-reported sleep quality and more self-reported time spent sitting than the Healthy Control group and the Premanifest-HD group, respectively. Conclusions: Sleep timing and physical activity relate to cognitive functioning in HD and may be important targets for management in behavioral intervention studies aimed at improving cognition in HD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Withdrawal or continuation of cholinesterase inhibitors or memantine or both, in people with dementia

BACKGROUND

Dementia is a progressive syndrome characterised by deterioration in memory, thinking and behaviour, and by impaired ability to perform daily activities. Two classes of drug - cholinesterase inhibitors (donepezil, galantamine and rivastigmine) and memantine - are widely licensed for dementia due to Alzheimer's disease, and rivastigmine is also licensed for Parkinson's disease dementia. These drugs are prescribed to alleviate symptoms and delay disease progression in these and sometimes in other forms of dementia. There are uncertainties about the benefits and adverse effects of these drugs in the long term and in severe dementia, about effects of withdrawal, and about the most appropriate time to discontinue treatment.

OBJECTIVES

To evaluate the effects of withdrawal or continuation of cholinesterase inhibitors or memantine, or both, in people with dementia on: cognitive, neuropsychiatric and functional outcomes, rates of institutionalisation, adverse events, dropout from trials, mortality, quality of life and carer-related outcomes.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group's Specialised Register up to 17 October 2020 using terms appropriate for the retrieval of studies of cholinesterase inhibitors or memantine. The Specialised Register contains records of clinical trials identified from monthly searches of a number of major healthcare databases, numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all randomised, controlled clinical trials (RCTs) which compared withdrawal of cholinesterase inhibitors or memantine, or both, with continuation of the same drug or drugs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed citations and full-text articles for inclusion, extracted data from included trials and assessed risk of bias using the Cochrane risk of bias tool. Where trials were sufficiently similar, we pooled data for outcomes in the short term (up to 2 months after randomisation), medium term (3-11 months) and long term (12 months or more). We assessed the overall certainty of the evidence for each outcome using GRADE methods.

MAIN RESULTS

We included six trials investigating cholinesterase inhibitor withdrawal, and one trial investigating withdrawal of either donepezil or memantine. No trials assessed withdrawal of memantine only. Drugs were withdrawn abruptly in five trials and stepwise in two trials. All participants had dementia due to Alzheimer's disease, with severities ranging from mild to very severe, and were taking cholinesterase inhibitors without known adverse effects at baseline. The included trials randomised 759 participants to treatment groups relevant to this review. Study duration ranged from 6 weeks to 12 months. There were too few included studies to allow planned subgroup analyses. We considered some studies to be at unclear or high risk of selection, performance, detection, attrition or reporting bias. Compared to continuing cholinesterase inhibitors, discontinuing treatment may be associated with worse cognitive function in the short term (standardised mean difference (SMD) -0.42, 95% confidence interval (CI) -0.64 to -0.21; 4 studies; low certainty), but the effect in the medium term is very uncertain (SMD -0.40, 95% CI -0.87 to 0.07; 3 studies; very low certainty). In a sensitivity analysis omitting data from a study which only included participants who had shown a relatively poor prior response to donepezil, inconsistency was reduced and we found that cognitive function may be worse in the discontinuation group in the medium term (SMD -0.62; 95% CI -0.94 to -0.31). Data from one longer-term study suggest that discontinuing a cholinesterase inhibitor is probably associated with worse cognitive function at 12 months (mean difference (MD) -2.09 Standardised Mini-Mental State Examination (SMMSE) points, 95% CI -3.43 to -0.75; moderate certainty). Discontinuation may make little or no difference to functional status in the short term (SMD -0.25, 95% CI -0.54 to 0.04; 2 studies; low certainty), and its effect in the medium term is uncertain (SMD -0.38, 95% CI -0.74 to -0.01; 2 studies; very low certainty). After 12 months, discontinuing a cholinesterase inhibitor probably results in greater functional impairment than continuing treatment (MD -3.38 Bristol Activities of Daily Living Scale (BADLS) points, 95% CI -6.67 to -0.10; one study; moderate certainty). Discontinuation may be associated with a worsening of neuropsychiatric symptoms over the short term and medium term, although we cannot exclude a minimal effect (SMD - 0.48, 95% CI -0.82 to -0.13; 2 studies; low certainty; and SMD -0.27, 95% CI -0.47 to -0.08; 3 studies; low certainty, respectively). Data from one study suggest that discontinuing a cholinesterase inhibitor may result in little to no change in neuropsychiatric status at 12 months (MD -0.87 Neuropsychiatric Inventory (NPI) points; 95% CI -8.42 to 6.68; moderate certainty). We found no clear evidence of an effect of discontinuation on dropout due to lack of medication efficacy or deterioration in overall medical condition (odds ratio (OR) 1.53, 95% CI 0.84 to 2.76; 4 studies; low certainty), on number of adverse events (OR 0.85, 95% CI 0.57 to 1.27; 4 studies; low certainty) or serious adverse events (OR 0.80, 95% CI 0.46 to 1.39; 4 studies; low certainty), and on mortality (OR 0.75, 95% CI 0.36 to 1.55; 5 studies; low certainty). Institutionalisation was reported in one trial, but it was not possible to extract data for the groups relevant to this review.

AUTHORS' CONCLUSIONS

This review suggests that discontinuing cholinesterase inhibitors may result in worse cognitive, neuropsychiatric and functional status than continuing treatment, although this is supported by limited evidence, almost all of low or very low certainty. As all participants had dementia due to Alzheimer's disease, our findings are not transferable to other dementia types. We were unable to determine whether the effects of discontinuing cholinesterase inhibitors differed with baseline dementia severity. There is currently no evidence to guide decisions about discontinuing memantine. There is a need for further well-designed RCTs, across a range of dementia severities and settings. We are aware of two ongoing registered trials. In making decisions about discontinuing these drugs, clinicians should exercise caution, considering the evidence from existing trials along with other factors important to patients and their carers.

Mendelian Randomization in Cardiovascular Research: Establishing Causality When There Are Unmeasured Confounders

Mendelian randomization is an epidemiological approach to making causal inferences using observational data. It makes use of the natural randomization that occurs in the generation of an individual's genetic makeup in a way that is analogous to the study design of a randomized controlled trial and uses instrumental variable analysis where the genetic variant(s) are the instrument (analogous to random allocation to treatment group in an randomized controlled trial). As with any instrumental variable, there are 3 assumptions that must be made about the genetic instrument: (1) it is associated (not necessarily causally) with the exposure (relevance condition); (2) it is associated with the outcome only through the exposure (exclusion restriction condition); and (3) it does not share a common cause with the outcome (ie, no confounders of the genetic instrument and outcome, independence condition). Using the example of type II diabetes and coronary artery disease, we demonstrate how the method may be used to investigate causality and discuss potential benefits and pitfalls. We conclude that although Mendelian randomization studies can usually not establish causality on their own, they may usefully contribute to the evidence base and increase our certainty about the effectiveness (or otherwise) of interventions to reduce cardiovascular disease.

Targeted, High-Resolution RNA Sequencing of Non-coding Genomic Regions Associated With Neuropsychiatric Functions

The human brain is one of the last frontiers of biomedical research. Genome-wide association studies (GWAS) have succeeded in identifying thousands of haplotype blocks associated with a range of neuropsychiatric traits, including disorders such as schizophrenia, Alzheimer's and Parkinson's disease. However, the majority of single nucleotide polymorphisms (SNPs) that mark these haplotype blocks fall within non-coding regions of the genome, hindering their functional validation. While some of these GWAS loci may contain cis-acting regulatory DNA elements such as enhancers, we hypothesized that many are also transcribed into non-coding RNAs that are missing from publicly available transcriptome annotations. Here, we use targeted RNA capture ('RNA CaptureSeq') in combination with nanopore long-read cDNA sequencing to transcriptionally profile 1,023 haplotype blocks across the genome containing non-coding GWAS SNPs associated with neuropsychiatric traits, using post-mortem human brain tissue from three neurologically healthy donors. We find that the majority (62%) of targeted haplotype blocks, including 13% of intergenic blocks, are transcribed into novel, multi-exonic RNAs, most of which are not yet recorded in GENCODE annotations. We validated our findings with short-read RNA-seq, providing orthogonal confirmation of novel splice junctions and enabling a quantitative assessment of the long-read assemblies. Many novel transcripts are supported by independent evidence of transcription including cap analysis of gene expression (CAGE) data and epigenetic marks, and some show signs of potential functional roles. We present these transcriptomes as a preliminary atlas of non-coding transcription in human brain that can be used to connect neurological phenotypes with gene expression.

An Australian community jury to consider case-finding for dementia: Differences between informed community preferences and general practice guidelines

Background

Case‐finding for dementia is practised by general practitioners (GPs) in Australia but without an awareness of community preferences. We explored the values and preferences of informed community members around case‐finding for dementia in Australian general practice.

Design, setting and participants

A before and after, mixed‐methods study in Gold Coast, Australia, with ten community members aged 50‐70.

Intervention

A 2‐day citizen/community jury. Participants were informed by experts about dementia, the potential harms and benefits of case‐finding, and ethical considerations.

Primary and secondary outcomes

We asked participants, “Should the health system encourage GPs to practice ‘case‐finding’ of dementia in people older than 50?” Case‐finding was defined as a GP initiating testing for dementia when the patient is unaware of symptoms. We also assessed changes in participant comprehension/knowledge, attitudes towards dementia and participants’ own intentions to undergo case‐finding for dementia if it were suggested.

Results

Participants voted unanimously against case‐finding for dementia, citing a lack of effective treatments, potential for harm to patients and potential financial incentives. However, they recognized that case‐finding was currently practised by Australian GPs and recommended specific changes to the guidelines. Participants increased their comprehension/knowledge of dementia, their attitude towards case‐finding became less positive, and their intentions to be tested themselves decreased.

Conclusion

Once informed, community jury participants did not agree case‐finding for dementia should be conducted by GPs. Yet their personal intentions to accept case‐finding varied. If case‐finding for dementia is recommended in the guidelines, then shared decision making is essential.

Incrementing the Frequency of Dynamic Strain on SMC-Cellularised Collagen-Based Scaffolds Affects Extracellular Matrix Remodeling and Mechanical Properties

Notwithstanding the efforts injected in vascular tissue engineering in the past 30 years, the clinical translation of engineered artery constructs is far from being successful. One common approach to improve artery regeneration is the use of cyclic mechanical stimuli to guide cellular remodeling. However, there is a lack of information on the effect of cyclic strain on cells within a 3D environment. To this end, this work explored the effect of gradual increase in stimulation frequency on the response of human umbilical artery smooth muscle cells (HUASMCs) embedded in a 3D collagen matrix. The results demonstrate that, with an applied strain of 5%, the gradual increase of frequency from 0.1 to 1 Hz improved collagen remodeling by HUASMCs compared to samples constantly stimulated at 1 Hz. The expression of collagen, elastin and matrix metalloproteinase-2 (MMP-2) genes was similar at 7 days for gradual and 1 Hz samples which showed lower amounts than static counterparts. Interestingly the mechanical properties of the constructs, specifically the amplitude of the time constants and the elastic equilibrium modulus, were enhanced by gradual increase of frequency. Taken together, these results show an increase in collagen remodeling by the HUASMCs overtime under incremental cyclic mechanical strain. This work suggests that only the in-depth investigation of the effects of stimulation parameters on the behavior of vSMC under cyclic strain in a 3D environment could lead to the design of optimized control strategies for enhanced vascular tissue generation and maturation in bioreactors.

Screening for Dementia in Primary Care: A Comparison of the GPCOG and the MMSE

BACKGROUND/AIMS

The General Practitioner Assessment of Cognition (GPCOG) is a brief cognitive test. This study compared the GPCOG to the Mini-Mental State Examination (MMSE), the most widely used test, in terms of their ability to detect likely dementia in primary care.

METHODS

General practitioners across three states in Australia recruited 2,028 elderly patients from the community. A research nurse administered the GPCOG and the MMSE, as well as the Cambridge Examination for Mental Disorders of the Elderly Cognitive Scale-Revised that we used to define likely dementia.

RESULTS

Overall, the GPCOG and the MMSE were similarly effective at detecting likely dementia. The GPCOG, however, had a higher sensitivity than the MMSE when using published cutpoints.

CONCLUSION

The GPCOG is an effective screening tool for dementia in primary care. It appears to be a viable alternative to the MMSE, whilst also requiring less time to administer.

Clinical Management of Neuropsychiatric Symptoms of Huntington Disease: Expert-Based Consensus Guidelines on Agitation, Anxiety, Apathy, Psychosis and Sleep Disorders

BACKGROUND

In clinical practice, several strategies and pharmacological options are available to treat neuropsychiatric symptoms of Huntington disease (HD). However, there is currently insufficient data for evidence-based guidelines on the management of these common symptoms.

OBJECTIVE

We aimed to develop expert-based recommendations regarding the management of agitation, anxiety, apathy, psychosis, and sleep disorders.

METHODS

Guideline development was based on a modified Institute of Medicine guideline process that accounted for a lack of evidence base. An international committee of 11 multidisciplinary experts proposed a series of statements regarding the description and management of each symptom. Statement assessment and validation was performed using a web-based survey tool and 84 international HD experts (neurologists and psychiatrists) who assessed the statements and indicated their level of agreement.

RESULTS

High-level agreement (≥85% experts strongly agreed or agreed) was reached for 107 of the 110 statements that have been incorporated into the expert-based clinical recommendations presented herein.

CONCLUSIONS

Clinical statements to guide the routine management of agitation, anxiety, apathy, psychosis, and sleep disorders in HD have been developed. Although not specifically tested in the HD population, clinical experience has shown that most of the neuropsychiatric symptoms discussed, when considered in isolation are treatable using pharmacologic and non-pharmacologic strategies developed for use in other populations. However, the management of neuropsychiatric symptoms in HD can be complex because neuropsychiatric symptoms often co-exist and treatment decisions should be adapted to cover all symptoms while limiting polypharmacy.

Safety of Converting From Tetrabenazine to Deutetrabenazine for the Treatment of Chorea

Importance

Tetrabenazine is efficacious for chorea control; however, tolerability concerns exist. Deutetrabenazine, a novel molecule that reduces chorea, was well tolerated in a double-blind, placebo-controlled study.

Objectives

To evaluate the safety and explore the efficacy of conversion from tetrabenazine to deutetrabenazine in patients with chorea associated with Huntington disease (HD).

Design, Setting, and Participants

In this ongoing, open-label, single-arm study that started on December 21, 2013, 37 patients at 13 Huntington Study Group sites in the United States and Australia who were taking stable doses of tetrabenazine that provided a therapeutic benefit were switched overnight to deutetrabenazine therapy. After week 1, the deutetrabenazine dose was titrated on a weekly basis for optimal chorea control.

Interventions

Deutetrabenazine administration at a dosage thought to provide comparable systemic exposure to the active metabolites of the prior, stable tetrabenazine regimen.

Main Outcomes and Measures

Safety measures included adverse events (AEs), clinical laboratory tests, vital signs, electrocardiograms, and validated scales. Changes in the Unified Huntington's Disease Rating Scale total maximal chorea score and total motor score were efficacy end points.

Results

Of the 53 patients with HD screened for the study, 37 ambulatory patients with manifest HD (mean [SD] age, 52.4 [11.5] years; 22 [59%] male and 15 [41%] female; 36 white [97.3%]) were enrolled. Deutetrabenazine was generally well tolerated, with low rates of neuropsychiatric AEs. Safety scales did not reveal subclinical toxicity with deutetrabenazine treatment. Rates of dose reduction or suspension attributable to AEs were also low. Chorea control, as measured by the total maximal chorea score, was maintained at week 1 and significantly improved at week 8 (mean [SD] change from baseline, 2.1 [3.2]; P < .001).

Conclusions and Relevance

In patients with chorea, overnight conversion to deutetrabenazine therapy provided a favorable safety profile and effectively maintained chorea control.

Why aren't people with young onset dementia and their supporters using formal services? Results from the INSPIRED study

Background/Aims

Despite reporting high levels of burden, supporters of people with young onset dementia (YOD) underuse formal community services. Previous quantitative studies in YOD are of limited utility in guiding service design because they did not consider important contextual barriers to service use. The aim of this study was to identify all relevant barriers and describe the service features considered most important to improving uptake by people with YOD and their supporters.

Methods

Eighty-six people with consensus-confirmed YOD (mean onset age 55.3 years) and/or their primary supporter participated in quantitative interviews, and 50 also participated in one of seven qualitative focus groups. Interview participants reported levels of community service use and reasons for non-use, functional impairment, behavioural and psychological symptoms, supporter burden, social network, and informal care provision. Focus group participants expanded on reasons for non-use and aspects of an ideal service.

Results

Although at least one community service was recommended to most participants (96.8%), 66.7% chose not to use one or more of these. Few of the clinical or demographic factors included here were related to service use. Qualitative analyses identified that lack of perceived need, availability, and YOD-specific barriers (including ineligibility, unaffordability, lack of security, lack of childcare) were commonly reported. Five aspects of an ideal service were noted: unique, flexibile, affordable, tailored, and promoting meaningful engagement.

Conclusion

People with YOD and their families report that formal community services do not meet their personal and psychological needs. Researchers can provide ongoing assessment of program feasibility, suitability, and generalisability.

Time to diagnosis in young-onset dementia and its determinants: the INSPIRED study

OBJECTIVE

The objective of this study is to identify factors determining the time to diagnosis for young-onset dementia (YOD), defined as dementia with symptom onset before age 65 years, by mapping the diagnostic pathways.

METHODS

Participants were recruited via healthcare professionals, community support organisations or were self-referred. Information was obtained by interviews with the person with YOD and their carer, and medical record reviews. Clinical dementia diagnoses were independently ratified by consensus review.

RESULTS

Participants included 88 people with YOD (mean age of onset = 55.4 years), due to Alzheimer's disease (AD) (53.4%, n = 47), frontotemporal dementia (FTD) (15.9%, n = 14) and other causes (30.7%, n = 27). Median time from symptom onset to first consultation was 2.3 years, to dementia diagnosis 3.2 years, to family awareness of dementia diagnosis 3.5 years and to final diagnosis of the type of dementia 4.7 years. Non-dementia diagnoses occurred in 48.9%, including depression (30.7%) and mild cognitive impairment (MCI) (17.0%). Participants with younger age of onset had significantly longer time to first consultation and family awareness of the dementia diagnosis. The time to dementia diagnosis was significantly longer when the participant presented with MCI or depression and when the dementia was other than AD or FTD. MCI was associated with significantly longer time to family awareness of dementia diagnosis.

CONCLUSIONS

Factors impacting on time to diagnosis vary with the stage of diagnosis in YOD. Longer time to dementia diagnosis occurred in people who were younger at symptom onset, when MCI or depression was present, and in dementias other than AD and FTD. Copyright © 2016 John Wiley & Sons, Ltd.

Unraveling the role of mechanical stimulation on smooth muscle cells: A comparative study between 2D and 3D models

A thorough understanding of cell response to combined culture configuration and mechanical cues is of paramount importance in vascular tissue engineering applications. Herein, we investigated and compared the response of vascular smooth muscle cells (vSMCs) cultured in different culture environments (2D cell monolayers and 3D cellularized collagen-based gels) in combination with mechanical stimulation (7% uniaxial cyclic strain, 1 Hz) for 2 and 5 days. When cyclic strain was applied, two different responses, in terms of cell orientation and expression of contractile-phenotype proteins, were observed in 2D and 3D models. Specifically, in 2D configuration, cyclic strain caused ∼50% of cell population to align nearly perpendicular (80-90 degrees) to the strain direction, while not influencing the contractile-phenotype protein expression, as compared to the 2D static controls. Conversely, the application of uniaxial strain to 3D constructs induced a ∼60% cell alignment almost parallel (0-10 degrees) to the strain direction. Moreover, 3D mechanical stimulation applied for 5 days induced a twofold increase of SM α-actin level and a 14-fold increase of calponin expression as compared to 3D static controls. Altogether these findings provide a new insight into the potential to drive cell behavior by modulating the extracellular matrix and the biomechanical environment. Biotechnol. Bioeng. 2016;113: 2254-2263. © 2016 Wiley Periodicals, Inc.

COGNITIVE-HD study: protocol of an observational study of neurocognitive functioning and association with clinical outcomes in adults with end-stage kidney disease treated with haemodialysis

INTRODUCTION

The prevalence of cognitive impairment may be increased in adults with end-stage kidney disease compared with the general population. However, the specific patterns of cognitive impairment and association of cognitive dysfunction with activities of daily living and clinical outcomes (including withdrawal from treatment) among haemodialysis patients remain incompletely understood. The COGNITIVE impairment in adults with end-stage kidney disease treated with HemoDialysis (COGNITIVE-HD) study aims to characterise the age-adjusted and education-adjusted patterns of cognitive impairment (using comprehensive testing for executive function, perceptual-motor function, language, learning and memory, and complex attention) in patients on haemodialysis and association with clinical outcomes.

METHODS AND ANALYSIS

A prospective, longitudinal, cohort study of 750 adults with end-stage kidney disease treated with long-term haemodialysis has been recruited within haemodialysis centres in Italy (July 2013 to April 2014). Testing for neurocognitive function was carried out by a trained psychologist at baseline to assess cognitive functioning. The primary study factor is cognitive impairment and secondary study factors will be specific domains of cognitive function. The primary outcome will be total mortality. Secondary outcomes will be cause-specific mortality, major cardiovascular events, fatal and non-fatal myocardial infarction and stroke, institutionalisation, and withdrawal from treatment at 12 months.

ETHICS AND DISSEMINATION

This protocol was approved before study conduct by the following responsible ethics committees: Catania (approval reference 186/BE; 26/09/2013), Agrigento (protocol numbers 61-62; 28/6/2013), USL Roma C (CE 39217; 24/6/2013), USL Roma F (protocol number 0041708; 23/7/2013), USL Latina (protocol number 20090/A001/2011; 12/7/2013), Trapani (protocol number 3413; 16/7/2013) and Brindisi (protocol number 40259; 6/6/2013). All participants have provided written and informed consent and can withdraw from the study at any time. The findings of the study will be disseminated through peer-reviewed journals and national and international conference presentations and to the participants through communication within the dialysis network in which this study is conducted.

Accuracy of musculoskeletal imaging for the diagnosis of polymyalgia rheumatica: systematic review

Objectives

To review the evidence for accuracy of imaging for diagnosis of polymyalgia rheumatica (PMR).

Methods

Searches included MEDLINE, EMBASE and PubMed. Evaluations of diagnostic accuracy of imaging tests for PMR were eligible, excluding reports with <10 PMR cases. Two authors independently extracted study data and three authors assessed methodological quality using modified QUADAS-2 criteria.

Results

26 studies of 2370 patients were evaluated: 10 ultrasound scanning studies; 6 MRI studies; 1 USS and MRI study; 7 18-fluorodeoxyglucose-positron emission tomography (PET) studies; 1 plain radiography and 1 technetium scintigraphy study. In four ultrasound studies, subacromial-subdeltoid bursitis had sensitivity 80% (95% CI 55% to 93%) and specificity 68% (95% CI 60% to 75%), whereas bilateral subacromial-subdeltoid bursitis had sensitivity 66% (95% CI 43% to 87%) and specificity 89% (95% CI 66% to 97%). Sensitivity for ultrasound detection of trochanteric bursitis ranged from 21% to 100%. In four ultrasound studies reporting both subacromial-subdeltoid bursitis and glenohumeral synovitis, detection of subacromial-subdeltoid bursitis was more accurate than that of glenohumeral synovitis (p=0.004). MRI and PET/CT revealed additional areas of inflammation in the spine and pelvis, including focal areas between the vertebrae and anterior to the hip joint, but the number of controls with inflammatory disease was inadequate for precise specificity estimates.

Conclusions

Subacromial-subdeltoid bursitis appears to be the most helpful ultrasound feature for PMR diagnosis, but interpretation is limited by study heterogeneity and methodological issues, including variability in blinding and potential bias due to case–control study designs. Recent MRI and PET/CT case–control studies, with blinded readers, yielded promising data requiring validation within a diagnostic cohort study.

Radiologists' perspectives about evidence-based medicine and their clinical practice: a semistructured interview study

OBJECTIVES

To describe radiologist's attitudes and perspectives on evidence-based medicine (EBM) and their practice.

DESIGN

Face-to-face semistructured interviews, thematic analysis.

SETTING

24 institutions across six Australian states and New Zealand. Transcripts were imported into HyperRESEARCH software and thematically analysed.

PARTICIPANTS

25 radiologists.

RESULTS

Six themes were identified: legitimising decisions (validated justification, prioritising patient preferences, reinforcing protocols), optimising outcomes (ensuring patient safety, maximising efficiency), availability of access (requiring immediacy, inadequacy of evidence, time constraints, proximity of peer networks, grasping information dispersion), over-riding pragmatism (perceptibly applicability, preserving the art of medicine, technical demands), limited confidence (conceptual obscurity, reputation-based trust, demands constant practice, suspicion and cynicism), and competing powers (hierarchical conflict, prevailing commercial interests).

CONCLUSIONS

Radiologists believe EBM can support clinical decision-making for optimal patient outcomes and service efficiency but feel limited in their capacities to assimilate and apply EBM in practice. Improving access to evidence, providing ongoing education and training supplemented with practical tools for appraising evidence; and developing evidence-based guidelines and protocols may enhance feasibility and promote the confidence and skills among radiologists in applying EBM in radiology practice for better patient care.

Increased workload for systematic review literature searches of diagnostic tests compared with treatments: challenges and opportunities

BACKGROUND

Comprehensive literature searches are conducted over multiple medical databases in order to meet stringent quality standards for systematic reviews. These searches are often very laborious, with authors often manually screening thousands of articles. Information retrieval (IR) techniques have proven increasingly effective in improving the efficiency of this process. IR challenges for systematic reviews involve building classifiers using training data with very high class-imbalance, and meeting the requirement for near perfect recall on relevant studies. Traditionally, most systematic reviews have focused on questions relating to treatment. The last decade has seen a large increase in the number of systematic reviews of diagnostic test accuracy (DTA).

OBJECTIVE

We aim to demonstrate that DTA reviews comprise an especially challenging subclass of systematic reviews with respect to the workload required for literature screening. We identify specific challenges for the application of IR to literature screening for DTA reviews, and identify potential directions for future research.

METHODS

We hypothesize that IR for DTA reviews face three additional challenges, compared to systematic reviews of treatments. These include an increased class-imbalance, a broader definition of the target class, and relative inadequacy of available metadata (ie, medical subject headings (MeSH) terms for medical literature analysis and retrieval system online). Assuming these hypotheses to be true, we identify five manifestations when we compare literature searches of DTA versus treatment. These manifestations include: an increase in the average number of articles screened, and increase in the average number of full-text articles obtained, a decrease in the number of included studies as a percentage of full-text articles screened, a decrease in the number of included studies as a percentage of all articles screened, and a decrease in the number of full-text articles obtained as a percentage of all articles screened. As of July 12 2013, 13 published Cochrane DTA reviews were available and all were included. For each DTA review, we randomly selected 15 treatment reviews published by the corresponding Cochrane Review Group (N=195). We then statistically tested differences in these five hypotheses, for the DTA versus treatment reviews.

RESULTS

Despite low statistical power caused by the small sample size for DTA reviews, strong (P<.01) or very strong (P<.001) evidence was obtained to support three of the five expected manifestations, with evidence for at least one manifestation of each hypothesis. The observed difference in effect sizes are substantial, demonstrating the practical difference in reviewer workload.

CONCLUSIONS

Reviewer workload (volume of citations screened) when screening literature for systematic reviews of DTA is especially high. This corresponds to greater rates of class-imbalance when training classifiers for automating literature screening for DTA reviews. Addressing concerns such as lower quality metadata and effectively modelling the broader target class could help to alleviate such challenges, providing possible directions for future research.

Dementia in Parkinson's disease: a 20-year neuropsychological study (Sydney Multicentre Study)

OBJECTIVE

To determine whether neuropsychological measures differ between patients with idiopathic Parkinson's disease (PD) who acquire dementia within 10 years of disease onset versus those who acquire dementia later in the disease course, using data from the longitudinal Sydney Multicentre Study of PD.

METHODS

The Sydney Multicentre Study of PD is a cohort of 149 community-living de novo patients with idiopathic PD studied over a 20-year period. Detailed clinical and neuropsychological tests were administered at baseline and at 3, 5, 10, 15 and 20 years, and the dementia status was assessed at each time point. For the present study, the pattern of longitudinal neuropsychological measures was compared between PD patients with the onset of dementia in the middle (5-10 years, mid-stage PD dementia, N = 20) or late (>10 years, late-stage PD dementia, N = 10) disease stages using analysis of variance and multiple linear regression modelling, and the relationship between age and dementia onset assessed using survival statistics.

RESULTS

Mid-stage PD dementia patients were differentiated from late-stage PD dementia patients by having greater deficits in vocabulary skills prior to and at dementia onset. The pattern of cognitive deficits following dementia onset are similar, and there is no difference in the age of dementia onset between the different PD groups.

CONCLUSIONS

These data suggest that the evolution of dementia within PD occurs at around 70 years of age, regardless of the time of PD onset, and affects cognitive domains in a similar way, although patients with earlier-onset PD have a preserved linguistic ability prior to dementia onset.

Low serum progranulin predicts the presence of mutations: a prospective study

Serum progranulin is decreased in frontotemporal dementia (FTD) patients with progranulin gene (PGRN) mutations. We investigate the utility of prospective serum screening as a surrogate diagnostic marker for progranulin mutations. A commercial ELISA was used to measure progranulin protein concentration in serum from 63 FTD patients and 32 normal controls, and DNA screening then performed. Four patients (2/17 behavioral variant, 2/8 corticobasal syndrome) had abnormally low progranulin levels with PGRN mutations confirmed on DNA testing. Surprisingly, elevated levels were found in 6/16 patients with progressive non-fluent aphasia, the significance of which is unclear. Serum testing is an accurate and cost effective means of predicting PGRN mutations.

Galantamine for Alzheimer's disease and mild cognitive impairment

BACKGROUND

Galantamine is a specific, competitive, and reversible acetylcholinesterase inhibitor.

OBJECTIVES

To assess the clinical effects of galantamine in patients with mild cognitive impairment (MCI), probable or possible Alzheimer's disease (AD), and potential moderators of effect.

SEARCH STRATEGY

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, last updated on 25 April 2005 using the terms galanthamin*, galantamin* and Reminyl. Published reviews were inspected for further sources. Additional information was collected from unpublished clinical research reports for galantamine obtained from Janssen and from http://www.clinicalstudyresults.org/.

SELECTION CRITERIA

Trials selected were randomised, double-blind, parallel-group comparisons of galantamine with placebo for a treatment duration of greater than 4 weeks in subjects with MCI or AD.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by the reviewers and pooled where appropriate and possible. Outcomes of interest include the clinical global impression of change (CIBIC-plus or CGIC), Alzheimer's Disease Assessment Scale-cognitive sub scale (ADAS-cog), Alzheimer's Disease Cooperative Study/Activities of Daily Living (ADCS-ADL), Disability Assessment for Dementia scale (DAD) and Neuropsychiatric Inventory (NPI). Potential moderating variables of treatment effect assessed included trial duration, dose, and diagnosis of possible versus probable Alzheimer's disease.

MAIN RESULTS

Ten trials with a total 6805 subjects were included in the analysis. Treatment with galantamine led to a significantly greater proportion of subjects with improved or unchanged global rating scale rating (k = 8 studies), at all dosing levels except for 8 mg/d . Confidence intervals for the ORs overlapped across the dose range of 16 mg to 36 mg per day, with point estimates of 1.6 - 1.8 when analysed with the intention-to-treat sample. Treatment with galantamine also led to significantly greater reduction in ADAS-cog score at all dosing levels (k = 8), with greater effect over six months compared to three months. Confidence intervals again overlapped. Point estimate of effect was lower for 8 mg/d but similar for 16 mg to 36 mg per day. For example, treatment effect for 24 mg/d over six months was 3.1 point reduction in ADAS-cog (95%CI 2.6-3.7, k = 4, ITT).ADCS-ADL, DAD and NPI were reported only in a small proportion of trials: all showed significant treatment effect in some individual trials at least. Confidence interval of treatment effect for the one trial recruiting patients with possible AD overlapped with the other seven recruiting patients with probable AD. Galantamine's adverse effects appeared similar to those of other cholinesterase inhibitors and to be dose related. Prolong release / once daily formulation of galantamine at 16 - 24mg/d was found to have similar efficacy and side-effect profile as the equivalent twice-daily regime. Data from the two MCI trials suggest marginal clinical benefit, but a yet unexplained excess in death rate.

AUTHORS' CONCLUSIONS

Subjects in these trials were similar to those seen in earlier anti dementia AD trials, consisting primarily of mildly to moderately impaired outpatients. Galantamine's effect on more severely impaired subjects has not yet been assessed.Nevertheless, this review shows consistent positive effects for galantamine for trials of three to six months' duration. Although there was not a statistically significant dose-response effect, doses above 8 mg/d were, for the most part, consistently statistically significant. Galantamine's safety profile in AD is similar to that of other cholinesterase inhibitors with respect to cholinergically mediated gastrointestinal symptoms. It appears that doses of 16 mg/d were best tolerated in the single trial where medication was titrated over a four week period, and because this dose showed statistically indistinguishable efficacy with higher doses, it is probably most preferable initially. Longer term use of galantamine has not been assessed in a controlled fashion. Galantamine use in MCI is not recommended due to its association with an excess death rate.

Galantamine for Alzheimer's disease

BACKGROUND

Galantamine is a specific, competitive, and reversible acetylcholinesterase inhibitor.

OBJECTIVES

To assess the clinical effects of galantamine in patients with probable or possible Alzheimer's disease (AD), and potential moderators of effect.

SEARCH STRATEGY

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, last updated on 25 August 2005 using the terms galanthamin*, galantamin* and Reminyl. Published reviews were inspected for further sources. Additional information was collected from unpublished clinical research reports for galantamine obtained from Janssen.

SELECTION CRITERIA

Trials selected were randomised, double-blind, parallel-group comparisons of galantamine with placebo for a treatment duration of greater than 4 weeks in subjects with AD.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by the reviewers and pooled where appropriate and possible. Outcomes of interest include the clinical global impression of change (CIBIC-plus or CGIC), Alzheimer's Disease Assessment Scale-cognitive sub scale (ADAS-cog), Alzheimer's Disease Cooperative Study/Activities of Daily Living (ADCS-ADL), Disability Assessment for Dementia scale (DAD) and Neuropsychiatric Inventory (NPI). Potential moderating variables of treatment effect assessed included trial duration, dose, and diagnosis of possible vs. probable Alzheimer's disease.

MAIN RESULTS

Seven trials with a total 3777 subjects were included in the analysis. Treatment with galantamine led to a significantly greater proportion of subjects with improved or unchanged global rating scale rating (k=7), at all dosing levels except for 8mg/d . Confidence intervals for the ORs overlapped across the dose range of 16mg to 36mg per day, with point estimates of 1.6-2.1 when analysed with the intention-to-treat sample. Treatment with galantamine also led to significantly greater reduction in ADAS-cog score at all dosing levels (k=7), with greater effect over 6 months compared to 3 months. Confidence intervals again overlapped. Point estimate of effect was lower for 8mg/d but similar for 16mg to 36mg per day. For example, treatment effect for 24mg/d over 6 months was 3.1point reduction in ADAS-cog (95%CI 2.6-3.7, k=4, ITT).ADCS-ADL, DAD and NPI were reported only in a small proportion of trials: all showed significant treatment effect in some individual trials at least. Confidence interval of treatment effect for the one trial recruiting patients with possible AD overlapped with the other six recruiting patients with probable AD. Galantamine's adverse effects appeared similar to those of other cholinesterase inhibitors and to be dose related.

REVIEWERS' CONCLUSIONS

Subjects in these trials were similar to those seen in earlier anti dementia AD trials, consisting primarily of mildly to moderately impaired outpatients. Galantamine's effect on more severely impaired subjects has not yet been assessed.Nevertheless, this review shows consistent positive effects for galantamine for trials of 3 to 6 months duration. Although there was not a statistically significant dose-response effect, doses above 8mg/d were, for the most part, consistently statistically significant. Galantamine's safety profile is similar to that of other cholinesterase inhibitors with respect to cholinergically mediated gastrointestinal symptoms. It appears that doses of 16 mg/d were best tolerated in the single trial where medication was titrated over a 4 week period, and because this dose showed statistically indistinguishable efficacy with higher doses, it is probably most preferable initially. Longer term use of galantamine has not been assessed in a controlled fashion.

Tau haplotypes regulate transcription and are associated with Parkinson's disease

A primary haplotype (H1) of the microtubule-associated protein Tau (MAPT) gene is associated with Parkinson's disease (PD). However, the mechanism for disease susceptibility remains unknown. We examined the promoter region of MAPT and identified single nucleotide polymorphisms and insertions of 1 to 11 nucleotides. These polymorphisms corresponded to the previously characterized haplotypes, H1 and H2, as well as a novel variant of the H1 haplotype, H1'. As observed in other studies, we demonstrated a significant association with the H1/H1 promoter genotype and PD in a cohort of 206 idiopathic late-onset cases. This is in contrast with a panel of 13 early-onset PD patients, for whom we did not detect any mutations in MAPT. By examining single nucleotide polymorphisms in adjacent genes, we showed that linkage disequilibrium does not extend beyond the MAPT haplotype to neighboring genes. To define the mechanism of disease susceptibility, we examined the transcriptional activity of the promoter haplotypes using a luciferase reporter assay. We demonstrated in two human cell lines, SK-N-MC and 293, that the H1 haplotype was more efficient at driving gene expression than the H2 haplotype. Our data suggest that an increase in expression of the MAPT gene is a susceptibility factor in idiopathic PD.

Accuracy of combined breast imaging in young women

This is a study of the accuracy of combined breast imaging (mammography and ultrasound) in young women with breast symptoms. We performed an appraisal of the literature, and improved our study design by avoiding biases identified in published work. Our study presents the sensitivity and specificity of mammography and breast ultrasound, individually and in combination, using different thresholds for categorizing test results, in a population of consecutive women. We show that combining the two imaging tests does improve sensitivity without significantly reducing test specificity. However, the number of additional cancers correctly identified using combined imaging, relative to the number of false positives, is highly dependent on breast cancer prevalence.

Recognition and invasion of human skin by Schistosoma mansoni cercariae: the key-role of L-arginine

The attachment of Schistosoma mansoni cercariae to mammalian skin is specifically stimulated by L-arginine. As L-arginine is an unsuitable signal for a specific identification of mammalian skin we examined the following 5 hypotheses to explain the advantage of the cercarial sensitivity to L-arginine. (1) A Schistosoma infection lowered the arginine concentration in the serum of mice, and this could enable the cercariae to avoid attachments to already infected mice. However, the infection did not reduce the arginine concentration in the skin and the cercarial attachment responses to it. (2) Creeping cercariae showed chemotactic orientation specifically along increasing L-arginine gradients. L-arginine could act as a pheromone which could guide cercariae towards common penetration sites. However, the cercarial acetabular gland contents were not attractive and they did not (in contrast to previous reports) contain much arginine. (3) Schistosomula (transformed cercariae) could use L-arginine to produce nitric oxide (NO) for blood vessel dilation during their migration in the host. However, in vitro the transformed cercariae did not convert L-arginine into citrulline and NO. (4) Schistosomula could bind L-arginine from the surrounding tissues and so escape the cellular immune attack (which needs L-arginine as the precursor of NO). However, transformed cercariae bound no more L-arginine than L-serine and L-lysine. (5) Schistosomula, migrating parallel to the surface in the mammalian epidermis, are dependent on information on their position between the inner and the surface layers of the skin. In the mouse skin, they adjusted their body axis with the ventral side toward the deeper (arginine-residue rich) epidermis layers. When migrating in agar, they showed chemo-orientation toward serum, and D-glucose and L-arginine were the stimulating compounds therein. The burrowing schistosomula adjusted their body axis (as in the epidermis) with the ventral side toward the higher concentration of L-arginine and not of glucose. We argue that the sensitivity for L-arginine has its primary function in orientation within mammalian skin and in location of blood vessels.

Prevalence of cercariae from Lymnaea stagnalis snails in a pond system in Southern Germany

Lymnaea stagnalis snails were collected from 174 individual ponds of an extensive pond system in South Germany; 43,441 snails collected during 1980 2000 were examined for shedding cercariae. The species richness (at least 18 species of cercariae) and the high cercarial prevalence (at least 44.9%) may result from the high abundance and diversity of vertebrate and invertebrate hosts in the area. The mean prevalence (% +/- SEM) of most cercarial species increased from May-June to August-October, e.g. in Diplostomum spathaceum from 4.1% to 18.6%, in all echinostomatids from 5.6% to 18.0%, in Pseudechinoparyphium echinatum from 3.0% to 11.2%, in Xiphidiocercariae from 2.2% to 13.4%, and the overall prevalence shifted from 13.7% to 53.5%. There was no change in the prevalence of the different cercarial species over the last 20 years. The agents of cercarial dermatitis showed a constant low prevalence, 0.17% in Trichobilharzia ocellata (43,441 L. stagnalis examined) and 0.24% in other Trichobilharzia species (4,245 Radix examined). Such low prevalences seem to be normal in areas where cercarial dermatitis occurs in humans.

Recognition of cattle skin by cercariae of Orientobilharzia turkestanica

The cercariae of Orientobilharzia turkestanica attached to isolated cattle skin and penetrated it. The attachment was stimulated by warmth and by hydrophilic and lipophilic chemical cues of skin surface extracts. The enduring contact with the skin was also stimulated by the chemical cues, but not by warmth. Penetration of the cercariae into agar substrates was triggered by skin surface lipids, and free fatty acids were identified as the exclusively active compounds of the lipids. That the cercariae attach and remain on the skin by responding to at least two different chemical host cues is unique among the schistosomatids studied so far. It might reflect an adaptation to invade the hosts in clear water or near the water surface where chemical mud compounds will not interfere with host recognition.

Photo- and geo-orientation by Echinostome cercariae results in habitat selection

The effect of light and gravity on orientation was studied in cercariae of 4 echinostome species: Pseudechinoparyphium echinatum, Echinostoma revolutum, Hypoderaeum conoideum, and Isthmiophora melis. The cercariae were placed into vertical and horizontal cuvettes, illuminated with 2 different light intensities from various directions, and their distribution recorded for 6 hr Each species showed its individual pattern of horizontal photo-orientation and geo-orientation, with distinct changes during the time after emerging. The geo-orientation was controlled differently in each species by the intensity and the direction of light radiation. The different orientation patterns suggest functions such as leaving the habitats of the host-snails emitting the cercariae, dispersal, and frequenting the microhabitats of potential hosts. The high diversity of orientation patterns among the species that originated from the same first intermediate host Lymnaea stagnalis in the same ponds and that invade similar host spectra suggests adaptations to different ecological conditions.

Effect of immersion of biopsy forceps in formalin on tissue urease activity

BACKGROUND AND AIMS

It is routine practice to wash biopsy forceps that have been immersed in formalin solution before taking gastric biopsies to test for urease activity as formalin is thought to inactivate the urease enzyme. The aim of this study was to assess the effect of pre-immersion of biopsy forceps in formalin solution on the ability to detect Helicobacter pylori urease activity in biopsies obtained with the same forceps.

METHODS

Two hundred consecutive patients undergoing gastroscopy who had macroscopic evidence of possible H. pylori infection had an initial antral biopsy taken using sterile forceps for determining biopsy urease activity. The same forceps were then used to obtain an antral biopsy for histological examination. The forceps were then used, without washing off any adherent formalin solution, to obtain a further antral biopsy for urease testing.

RESULTS

The concordance rate for urease tests, with or without formalin exposure, was 100% (95% confidence interval (CI) 98.2-100%). Fifty-six of 200 patients (28%) were found to have urease-positive biopsies. Of these, 52/56 (92.9%) had identifiable H. pylori on histopathology. One hundred and forty-four of 200 patients (72%) were found to have urease-negative biopsies. Of these, seven (4.9%) had identifiable H. pylori on histopathology. Six of seven (85.7%) had only a small number of organisms identified. The sensitivity and specificity for the urease test compared with the histopathology as a reference standard was 88.1% (95% CI 79.9-96.4%) and 97.2% (95% CI 94.4-99.9%), respectively.

CONCLUSION

Immersion of biopsy forceps in formalin did not reduce the ability to detect urease activity in gastric biopsies taken subsequently.

Schistosoma mansoni cercariae: stimulation of acetabular gland secretion is adapted to the chemical composition of mammalian skin

The chemical signals of mammalian skin that stimulate the secretion of acetabular gland contents of Schistosoma mansoni cercariae were determined by exposing cercariae to fractions of human and pig skin surface obtained by thin-layer chromatography. Postacetabular gland secretion was stimulated by hydrophilic skin extracts but was often combined with a secretion of preacetabular glands. Secretion of preacetabular glands, which contain enzymes for skin lysis, could be selectively stimulated with skin surface lipids. Two different mechanisms of lipid-stimulated preacetabular gland release could be distinguished. First, secretion in combination with penetration behavior and probably tegument transformation was stimulated by the fraction of free fatty acids. Second, secretion independent of penetration behavior and tegument transformation was exclusively stimulated by glucosylceramides and phospholipids, probably phosphatidylcholines. The secretion mechanisms seem to allow a continuous lysis of epidermal macromolecules during the skin passage of the cercariae. Free fatty acids occur in the uppermost skin layers and may stimulate the combination of the first response; phospholipids and glucosylceramides are restricted to deeper epidermal layers and may stimulate the enzyme secretion there. An active preacetabular gland release was also stimulated by toxic chemicals, which could suggest an emergency penetration program for impaired cercariae.