Use of diamond sensors for a high-flux, high-rate X-ray pass-through diagnostic

X-ray free-electron lasers (XFELs) deliver pulses of coherent X-rays on the femtosecond time scale, with potentially high repetition rates. While XFELs provide high peak intensities, both the intensity and the centroid of the beam fluctuate strongly on a pulse-to-pulse basis, motivating high-rate beam diagnostics that operate over a large dynamic range. The fast drift velocity, low X-ray absorption and high radiation tolerance properties of chemical vapour deposition diamonds make these crystals a promising candidate material for developing a fast (multi-GHz) pass-through diagnostic for the next generation of XFELs. A new approach to the design of a diamond sensor signal path is presented, along with associated characterization studies performed in the XPP endstation of the LINAC Coherent Light Source (LCLS) at SLAC. Qualitative charge collection profiles (collected charge versus time) are presented and compared with those from a commercially available detector. Quantitative results on the charge collection efficiency and signal collection times are presented over a range of approximately four orders of magnitude in the generated electron-hole plasma density.

The sourcing and use of high physical resemblance personal protective equipment to train healthcare workers, improve confidence and conserve medical-grade equipment

Personal protective equipment (PPE) is essential for healthcare worker (HCW) safety. Conservation of PPE for clinical use during the COVID-19 pandemic reduced its availability for training, necessitating an innovative approach to sourcing high physical resemblance PPE (HPR-PPE). We present a case study of crowd-sourcing of HPR-PPE to train HCWs. Survey results indicated that HPR-PPE enabled high-fidelity practise of PPE application and removal, aided procedure recall, improved user confidence and was sufficiently similar to medical-grade PPE. HPR-PPE provided a novel and cost-effective alternative. We also demonstrated that medical-grade PPE can be sourced from non-medical institutions and businesses during a pandemic.

142 Improving Functional Outcomes During Covid-19 for Both COVID-19 and Non COVID-19 Positive Older Adults Through the Introduction

Purpose

To improve the functional outcomes of older adults presenting to the Health and Ageing wards during the COVID-19 pandemic through a focussed rehabilitation list. The intended benefits to the older adult and service were for: 1. Daily rehabilitation input for older adults. 2. Older adults to spend less time immobile. 3. Ongoing rehabilitation intervention while awaiting medical clearance for discharge. 4. Increased staff satisfaction 5. Better outcomes on discharge. 6. Rehabilitation ethos on the Health and Ageing wards.

Methods

The quality improvement project was carried out using the Plan, Do, Study, Act (PDSA) cycle. Three iterative PDSA cycles were carried out over the course of the project to deliver proactive interventions as a result of analysis of baseline data and stakeholder involvement. These interventions were aimed at developing communication around the rehabilitation list within the team and sustainability of this list.

Results

The project resulted in better functional outcomes for older adults and increased staff morale. Between May 2020–June 2020, a total of 56 patients were seen on the rehabilitation list, with 84% of these patients seeing improvements in their Elderly Mobility Scores (EMS). 27% of patients on the rehabilitation list saw a change to their initial discharge plan, either needing reduced packages of care or reduced need for ongoing rehabilitation in an external setting.

Conclusions

The quality improvement project found that with focussed rehabilitation older adult inpatients with or without COVID-19 can make significant functional gains. These gains have wider effects on their outcomes on discharge and also for the service through increased morale and job satisfaction. Due to demand and capacity issues in the acute setting, older adults who would often benefit from ongoing input are not always reviewed regularly. This project demonstrates that with focussed rehabilitation older adults can improve and achieve better functional outcomes.

Reduced NT-proBNP threshold for risk prediction in high-risk elderly with subclinical heart failure: support from cardiopulmonary exercise testing

Background

Subclinical heart failure (HF) is divided into Stage A and B (SAHF and SBHF) depending on structural or functional cardiac abnormalities. However, risk of HF progression is not solely dependent on echocardiographic abnormalities. Data on oxygen consumption (VO2) and other prognostic cardiopulmonary exercise test (CPET) markers in subclinical HF, particularly in the elderly, is lacking. VO2 may refine risk prediction and provide pathological insight in subclinical HF.

Methods

Asymptomatic individuals were recruited through primary care if they were ≥65 years with ≥1 non-ischaemic risk factor for HF. Clinical evaluation determined risk profile, biometrics and NT-proBNP. Treadmill CPET was undertaken with a modified Bruce protocol. Low V02 was defined as ≤20th percentile of age and gender specific VO2 in healthy individuals. SBHF defined as systolic (global longitudinal strain, GLS ≤16%), diastolic (E/e' ≥15, E/e' >10 with left atrial enlargement or impaired relaxation with other changes or left ventricular (LV) hypertrophy (LV mass index >95 g/m2 in women or >115 g/m2 in men).

Results

Of the 91 included individuals (age 71±4 years, 53% female), 46 (51%) had SBHF, average NT-proBNP was 60pg/ml (26–99mg/ml) and did not differ by HF stage (59 [26–85] pg/ml vs. 60 [30–99] pg/ml for Stage A vs. B respectively, p=0.94). Average peak VO2 was 19.8 (16–22.6) ml/kg/min and was low in 71 (78%). VO2 did not differ by HF stage (19.9 [17.7–22.4] ml/kg/min vs. 19.7 [16–22.8] ml/kg/min for SAHF vs. SBHF respectively, p=0.62). NT-proBNP was significantly higher in those with abnormal VO2 (66 [34–110] pg/ml vs 31 [20–70] pg/ml, p=0.016). Within each HF stage, low VO2 was associated with higher NT-proBNP (Figure). Of those with NT-proBNP >100pg/ml, 95% (22/23) had low VO2 compared with 72% of those ≤100pg/ml, p=0.02 (non-signifcant for 125pg/ml cut-off). No associations were found between SBHF or individual echo abnormalities and VO2. In logistic regression analysis NT-proBNP was a significant univariable predictor of low VO2 and remained significant after adjustment for other significant univariables (BMI) (OR 1.02 [95% CI 1.0001–1.03], p=0.048).

Conclusion

Low VO2 identifies a high-risk cardiac phenotype within subclinical HF stages, but is not necessarily associated with LV dysfunction. Levels of NT-proBNP beneath the cut-off used for HF exclusion may assist risk stratification in this population.

NT-proBNP by VO2 in subclinical HF

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Dr E Potter is supported by a PhD Scholarship from Monash University, Melbourne, Australia

Clinical communication preferences in cystic fibrosis and strategies to optimize care

BACKGROUND

The importance of optimizing communication between clinicians and individuals and families living with cystic fibrosis (CF) about daily care, adherence, and related psychosocial concerns is well documented. The purpose of this study was to gain an understanding of interpersonal communication experiences and preferences among individuals and families living with CF as they engage with the clinical team. The study also aimed to reveal opportunities for enhancing future interpersonal communication practices.

METHODS

Five U.S. CF care centers participated in the following activities: (a) On-site observation of clinic interactions during outpatient visits; (b) On-site 1:1 interviews with individuals living with CF, their family members, and CF clinicians; (d) Focus groups conducted in person with CF care team members; (d) Focus groups conducted virtually with adults and family members with CF. Content analysis of transcripts and constant comparative methods were used to identify emergent themes.

RESULTS

Four themes related to participants' needs and preferences for clinic interactions emerged during analysis: (a) eliciting psychosocial concerns, (b) addressing childhood development and transitions, (c) negotiating agendas and sharing decisions, and (d) educating to enhance CF conversations.

CONCLUSION

CF clinicians and individuals and families living with CF expressed the need for resources and training to engage in better conversations with each other. Participants identified areas of high priority, including working together around social, psychological, and economic challenges, preparation for transition to adulthood, and sustaining daily care. Findings point to the value of developing advanced communication skills that foster trust-building, negotiating agendas, active listening, and collaborative goal-setting.

P1482Preclinical diastolic dysfunction assessed by left atrial strain and association with incident heart failure

Background

Left atrial strain in the reservoir phase (LASr) measures passive LA stretch and is a sensitive marker of left ventricular diastolic dysfunction (DD). However, reduced LASr has not been prospectively validated against clinical heart failure (HF) endpoints and its place in diastology evaluation is unclear.

Aim

We sought whether DD grades defined by previously validated ranges of LASr predicted incident HF and whether reclassifying indeterminate diastolic function based on reduced LASr could facilitate assessment of HF risk.

Methods

Community dwelling elderly subjects were recruited and underwent baseline clinical and echocardiographic assessment. Where imaging was suitable, speckle-tracking echocardiography assessed LASr and subjects were assigned DD grades based on published ranges: normal >35%, grade 1 24–35%, grade 2 19–24%, grade 3 <19%. Current ASE/EACVI recommendations were used to identify those with indeterminate function; LASr-defined DD (LASr-DD) was defined as LASr ≤23%. Follow-up was ≤2 years and incident HF adjudicated by Framingham criteria.

Results

Of 610 subjects (age 71±5 yrs., 46% male) LASr analysis was feasible in 590 (97%); average LASr was 39% (IQR 34–43%). Incident HF was associated with LASr-DD grade, occurring in 8 (36%) with grade ≥2, 14 (10%) with grade 1 and 39 (9%) with normal function (p<0.001). Adjusted odds ratio for incident HF for LASr-DD grade ≥2 was 3.12 (95% CI 1.06–9.1, p=0.038) Diastolic function was indeterminate in 147 (24%) subjects; of 144 (98%) with LAS analysis, 6 (75%) of those with LASr-DD vs. 15 (11%) with normal LASr experienced incident HF (p<0.001).

Univariable Multivariable* OR (95% CI) p-value OR (95% CI) p-value LASr-DD grade:   1 1.13 (0.59–2.15) 0.7 0.84 (0.42–1.69) 0.63   ≥2 5.7 (2.26–14.5) <0.001 3.12 (1.06–9.1) 0.038 *Adjusted for age, hypertension, diabetes, BMI, global longitudinal strain, E/e', LA volume index, LV mass index (all p<0.1 on univariable analysis).

Incorporating LA strain in practice

Conclusion

DD defined by LASr is predictive of HF for grades ≥2 independent of other diastolic measures. Indeterminate diastolic function with LASr ≤23% is associated with incident HF. LASr may complement current diastolic function assessment recommendations.

Acknowledgement/Funding

Baker Heart and Diabetes Institute

P3431Machine learning applied to energy waveform ECG for prediction of subclinical myocardial dysfunction

Background

Energy waveform (ew) ECG used continuous wavelet transforms (CWT) to create time-frequency energy characterisations. Although ewECG changes reflect myocardial disease, the optimal measures for prediction of subclinical left ventricular dysfunction (sLVD) are unclear.

Aim

Using machine learning, we investigated whether ewECG could predict sLVD in community subjects at risk of heart failure (HF).

Methods

Asymptomatic community subjects aged ≥65 yrs. with ≥1 non-ischaemic risk factor for HF underwent clinical evaluation, MyoVista (HeartSciences, Southlake, TX) ewECG and echocardiographic evaluation. sLVD was defined as systolic (global longitudinal strain, GLS≤16%) or diastolic (E/e' ≥15, E/e'>10 with left atrial enlargement, or impaired relaxation with other changes). A gradient boosting algorithm (supervised machine learning) with regularisation was implemented to predict sLVD using 362 ewECG features. The performance was assessed by precision, recall, F measure, precision-recall (PR) curve and receiver operating characteristic (ROC) curve. Feature importance was inspected by information gain node splitting.

Results

Of 97 subjects (age 71 (68–73) yrs., 53% female) 56 (58%) had sLVD. For prediction of sLVD, ewECG showed areas under PR and ROC curves of 0.86 and 0.8 respectively. The feature of greatest importance, with twice the importance of the second was a CWT frequency related to depolarisation.

Baseline characteristics Hypertension (%) 83 (86) Diabetes Mellitus (%) 34 (36) Atrial Fibrillation (%) 8 (8) BMI (IQR) 31 (27–34) LVMi (SD) 73 (23) Ejection fraction (SD) 60 (6) GLS (SD) 18 (3) E/e' (IQR) 8 (7–10) LAVi (IQR) 33 (28–40) IQR, Interquartile range; BMI, body mass index; LVMi, left ventricular mass index; GLS, global longitudinal strain; LAVi, left atrial volume index.

Prediction model performance

Conclusion

ewECG shows good predictive performance for sLVD in elderly subjects at risk of HF. HF prevention strategies incorporating ewECG to select individuals for echocardiographic evaluation should be considered.

Acknowledgement/Funding

Baker Heart and Diabetes Institute

P5979Impact of disease stage on performance of strain markers for prediction of atrial fibrillation

Background

Efforts to predict incident atrial fibrillation (AF) may be associated with complications, and there is interest in AF prediction in primary prevention (PP; pts with risk factors) and secondary prevention (SP; pts with possible AF complications). These pts have different risk levels, we sought whether that influenced the predictive value of LV dysfunction (measured as global longitudinal strain, GLS) or LA dysfunction (LA reservoir strain).

Methods

The PP cohort comprised 351 community-based pts ≥65 years with ≥1 risk factor for AF (age 70±4y,43% male, median follow-up 22 months) and the SP cohort comprised 532 pts after transient ischaemic attack or stroke (age 68±12y, 51% male, median follow-up 36 months). GLS and LA strain were measured offline (Image Arena-Tomtec, Germany). AF was diagnosed by 12 lead ECG, Holter or by single lead monitor. The clinical and echocardiographic characteristics of those with AF were compared to those in sinus rhythm. Nested Cox-regression models were used to assess for independent and incremental predictive value of LA strain/GLS in both cohorts.

Results

Compared to SP, PP had higher clinical AF risk (CHARGE-AF 5.6±5.5% vs 4.7±12.1%, p=0.02) but a lower thromboembolic risk (CHA2DS2-VASC 3±2 vs. 4±2, p<0.001). AF developed in 42 PP pts (12%) and 61 SP (12%). AF patients were older, with higher CHARGE-AF score, LA volume and LV mass. Pts developing AF had reduced GLS (17±4% vs. 20±3%, p<0.001), reservoir (28±11% vs. 35±8%, p<0.001) and pump strain (13±7% vs. 17±5%, p<0.001). GLS and LA strain had greater AUC in SP (0.84 vs 0.58 for GLS and 0.85 vs 0.57 for reservoir strain, both p<0.001). Nested cox-regression models showed that LA reservoir strain was independently associated with AF in both cohorts (p<0.05). GLS was only independently associated with incident AF in SP (Figure).

Conclusion

LA reservoir strain is independently associated with AF in different risk cohorts and its effect is incremental to clinical parameters and LA volume. GLS may be more useful in AF risk assessment in those in SP.

Acknowledgement/Funding

This study was partially supported by the Tasmanian Community Fund and Siemens Healthcare Australia.

Aminoglycoside resistance of Pseudomonas aeruginosa in cystic fibrosis results from convergent evolution in the mexZ gene

RATIONALE

Aminoglycoside (AG) resistance of Pseudomonas aeruginosa in cystic fibrosis (CF) is associated with poorer clinical outcomes and is usually due to overexpression of the efflux pump MexXY. MexXY is regulated by mexZ, one of the most commonly mutated genes in CF P. aeruginosa isolates. Little is known about the evolutionary relationship between AG resistance, MexXY expression and mexZ mutations.

OBJECTIVES

To test the hypothesis that AG resistance in P. aeruginosa develops in parallel with higher MexXY expression and mexZ mutations.

METHODS

CF P. aeruginosa isolates were compared for chronically infected (CI) adults, CI children and children with new infection.

MEASUREMENTS

One P. aeruginosa isolate from each patient was analysed for mexZ mutations, mexY mRNA expression and amikacin resistance.

MAIN RESULTS

56 patients with CF were enrolled: 21 children with new P. aeruginosa infection, 18 CI children and 17 CI adults. Amikacin resistance and mexY mRNA expression were higher in cohorts with longer P. aeruginosa infection. The prevalence of non-conservative mexZ mutations was 0%, 33% and 65% in children with new infection, CI children and CI adults, respectively. The same trend was seen in the ratio of non-conservative to non-synonymous mexZ mutations. Of isolates with non-conservative mexZ mutations, 59% were amikacin-resistant compared with 18% of isolates with non-synonymous mutations. The doubling rate of amikacin resistance and non-conservative mexZ mutations was approximately 5 years.

CONCLUSIONS

P. aeruginosa mexZ mutations undergo positive selection resulting in increased mexY mRNA expression and amikacin resistance and likely play a role in bacterial adaption in the CF lung.

Association of white matter hyperintensity measurements on brain MR imaging with cognitive status, medial temporal atrophy, and cardiovascular risk factors

BACKGROUND AND PURPOSE

White matter hyperintensities (WMHs) are frequently characterized as markers of cerebrovascular disease, whereas medial temporal atrophy (MTA) is a recognized marker of Alzheimer disease (AD). Our purpose was to test the reliability of a visual rating system (VRS) in evaluating WMHs and MTA and in distinguishing healthy from cognitively impaired subjects.

MATERIALS AND METHODS

Subjects (n = 192) enrolled in the Florida Alzheimer's Disease Research Center were diagnosed with no cognitive impairment, nonamnestic mild cognitive impairment (na-MCI), amnestic MCI (a-MCI), or probable AD. The severity of WMHs was assessed on T2-weighted fluid-attenuated inversion recovery axial MR images, and the severity of MTA was evaluated on 1.5-mm-thick coronal MR images by using a computer-based visual rating system. Cardiovascular risk factor scores were calculated as the sum of 10 independent cardiovascular risk factors.

RESULTS

WMH and MTA scores were greater in subjects with probable AD, relative to those with no cognitive impairment and na-MCI. MTA scores differentiated subjects with a-MCI from those with no cognitive impairment and na-MCI. The total WMH score was significantly related to MTA (r = 0.39; P < .001) but not to cardiovascular risk factor scores (r = 0.07; P = not significant). The overall correct classification rate of probable AD versus no cognitive impairment by using MTA scores was 81.8%, improving to 86.5% when combined with WMH scores.

CONCLUSIONS

Both MTA and WMH scores distinguished subjects with no cognitive impairment and probable AD. Combining MTA and WMH scores improved the correct classification rate, whereas WMH scores were significantly related to MTA scores, but not to cardiovascular risk factor scores. This finding suggests that among subjects with a-MCI and probable AD, WMHs on MR images are primarily associated with neurodegenerative disease.

The comparative toxicity to soil invertebrates of natural chemicals and their synthetic analogues

The introduction of Registration, Evaluation and Authorisation of Chemicals (REACH), requires companies to register and risk assess all substances produced or imported in volumes of >1 tonne per year. Extrapolation methods which use existing data for estimating the effects of chemicals are attractive to industry, and comparative data are therefore increasingly in demand. Data on natural toxic chemicals could be used for extrapolation methods such as read-across. To test this hypothesis, the toxicity of natural chemicals and their synthetic analogues were compared using standardised toxicity tests. Two chemical pairs: the napthoquinones, juglone (natural) and 1,4-naphthoquinone (synthetic); and anthraquinones, emodin (natural) and quinizarin (synthetic) were chosen, and their comparative effects on the survival and reproduction of collembolans, earthworms, enchytraeids and predatory mites were assessed. Differences in sensitivity between the species were observed with the predatory mite (Hypoaspis aculeifer) showing the least sensitivity. Within the chemical pairs, toxicity to lethal and sub-lethal endpoints was very similar for the four invertebrate species. The exception was earthworm reproduction, which showed differential sensitivity to the chemicals in both naphthoquinone and anthraquinone pairs. Differences in toxicity identified in the present study may be related to degree of exposure and/or subtle differences in the mode of toxic action for the chemicals and species tested. It may be possible to predict differences by identifying functional groups which infer increased or decreased toxicity in one or other chemical. The development of such techniques would enable the use of read-across from natural to synthetic chemicals for a wider group of compounds.

Medial temporal lobe atrophy on MRI scans and the diagnosis of Alzheimer disease

BACKGROUND

Despite convenience, accessibility, and strong correlation to severity of Alzheimer disease (AD) pathology, medial temporal lobe atrophy (MTA) has not been used as a criterion in the diagnosis of prodromal and probable AD.

METHODS

Using a newly validated visual rating system, mean MTA scores of three bilateral medial temporal lobe structures were compared for subjects with no cognitive impairment (NCI) (n = 117), nonamnestic mild cognitive impairment (MCI) (n = 46), amnestic MCI (n = 45), and probable AD (n = 53). Correlations between MTA scores and neuropsychological test scores at baseline, and predictors of change in diagnosis at 1-year follow-up were evaluated.

RESULTS

With NCI as the reference group, a mean MTA cut score of 1.33 yielded an optimal sensitivity/specificity of 85%/82% for probable AD subjects and 80%/82% for amnestic MCI subjects. MTA and Clinical Dementia Rating Sum of Boxes scores at baseline were independent and additive predictors of diagnosis at baseline, and of transition from NCI to MCI or from MCI to dementia at 1-year follow-up.

CONCLUSION

Medial temporal lobe atrophy (MTA) scores 1) distinguish probable Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI) subjects from nonamnestic MCI and no cognitive impairment (NCI) subjects, 2) help predict diagnosis at baseline, and 3) predict transition from NCI to MCI and from MCI to probable AD. MTA scores should be used as a criterion in the clinical diagnosis of AD.

Evolution of Pseudomonas aeruginosa type III secretion in cystic fibrosis: a paradigm of chronic infection

Pseudomonas aeruginosa (PA) from acute and chronic (eg, cystic fibrosis (CF)) infections differ in several respects, but they can worsen prognosis in each context. Factors that facilitate conversion from an acute to chronic phenotype are poorly understood. T3 secretion proteins are virulence factors associated with poorer outcomes in acute infections, but little is known about their role in CF. We wished to characterize T3 secretion in CF PA isolates and to examine its role in clinical outcomes. A total of 114 CF subjects were divided into 3 cohorts: 1st infected individuals, CI children, and adults. Serial respiratory cultures were analyzed for T3 secretion. Serial spirometry and exacerbation data were collected prospectively. In 1st infection, 45.2% +/- 9.1% of PA isolates secreted T3 proteins compared with 29.1% +/- 4.2% and 11.5% +/- 3.0% in CI children and CI adults, respectively (P < 0.001). An inverse correlation was observed between duration of PA infection and percent T3 positive isolates (r = -0.32, P < 0.001). Overall, no association was observed between T3 secretion and pulmonary outcomes, but in the subgroup of subjects who had at least 1 T3 positive organism, T3 secretion was inversely correlated with the forced expiratory volume in 1 s (FEV(1)) decline (r = -0.35, P = 0.02). In 1st infection, 82% of cultures grew either all or no T3-positive organisms. In these patients, T3 secretion was associated with a greater risk of subsequent PA isolation (P < 0.001). In CF, PA T3 secretion decreases with residence time in lung, may predict FEV(1) decline in patients who have detectable T3 organisms, and may facilitate persistence after 1st infection.

White matter brain lesions in midlife familial hypercholesterolemic patients at 3-Tesla magnetic resonance imaging

BACKGROUND

Patients with hypercholesterolemia of 60 years and older have an increased risk for white matter brain lesions and dementia.

PURPOSE

To investigate whether patients with familial hypercholesterolemia (FH) develop white matter lesions at 3-Tesla (T) MRI as early as in midlife.

MATERIAL AND METHODS

Non-diabetic, nonsmoking, and non-hypertensive heterozygous FH patients on treatment with maximally tolerated dose of a statin for more than 5 years (n = 14) and matched controls (n = 22) aged 25 to 60 years of age were studied. Imaging was performed at 3T with a fluid-attenuated T2-weighted MR pulse sequence and a T1-weighted spin-echo pulse sequence following 10 ml of i.v. gadopentetate dimeglumine. Images were evaluated by two independent readers. Fasting blood samples were taken. Student's t test was employed at P<0.05.

RESULTS

Three volunteers and one FH patient had white matter lesions (P<0.53). No other evidence of past ischemic stroke was observed. Mean total serum cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the FH group (6.0+/-1.1 vs. 5.1+/-0.9 mmol/l, P<0.02 and 4.1+/-0.9 vs. 3.1+/-0.8 mmol/l, P<0.004, respectively).

CONCLUSION

Heterozygous FH patients on statin treatment in the age range of 25 to 60 years are not at increased risk of white matter lesions at 3T MRI.

The relationship between exercise and hopelessness in prison

This paper reports on the relationship between the levels of self-reported physical exercise and mental well-being (as measured using the Beck Hopelessness Scale) in a cohort of 914 prisoners within New South Wales, Australia. A significant inverse relationship between self-reported exercise in minutes per week and hopelessness was identified. The need to include exercise as a factor in inmate health plans is discussed.

The functional neuroanatomy of corticotropin-releasing factor

Descriptions of the central distribution of corticotropin-releasing factor (CRF) have been taken as generally supporting the proposition that this neuropeptide is involved in the mediation of complementary neuroendocrine, autonomic and behavioural responses to stress. The hypothalamic paraventricular nucleus (PVN) is recognized as the principal source of CRF in hypophysial portal plasma; CRF mRNA and peptide expression in parvocellular neurosecretory neurons are regulated negatively by adrenal steroids and positively by many stressors. Consistent with the latter, the hypophysiotropic zone of the PVN receives a rich, and biochemically differentiated, afferent supply that provides visceral, somatic and special sensory systems with access to the 'CRF neuron'. Within the PVN, CRF is also expressed, and differentially regulated, in oxytocinergic magnocellular neurosecretory neurons and in autonomic-related projection neurons. CRF expression in at least some extrahypothalamic cell groups (olfactory bulb, Barrington's nucleus) is responsive to certain stressful stimuli, but not to perturbations of the steroid environment. Refinement of our understanding of the central distribution of CRF has been provided by the recognition that most CRF antisera cross-react with an amidated dipeptide encoded by the melanin-concentrating hormone precursor, and by the likelihood that some central sites of CRF peptide expression may be muted or masked by the presence of a CRF-binding protein (CRF-BP). The CRF-BP is expressed prominently in the telencephalon, where it is co-localized with CRF in some neurons, and in anterior pituitary corticotrophs.

Oncofoetal fibronectin--a tumour-specific marker in detecting minimal residual disease in differentiated thyroid carcinoma

Supposedly, thyrocyte-specific transcripts such as thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R) were proposed to be useful for the diagnosis of circulating tumour cells in patients suffering from differentiated thyroid carcinoma (DTC). However, several research groups reported blood-borne Tg transcripts in healthy individuals. This study determines in particular the origin of Tg mRNA in nucleated blood cells and analyses whether other tumour-associated sequences are absent in leukocytes, but widely expressed in DTC. Therefore, expression analyses for Tg, TSH-R, cytokeratin 19 (CK 19), human telomerase reverse transcriptase (hTERT) and oncofoetal fibronectin (onfFN) were carried out using cDNAs derived from (1) leukocyte fractions, (2) 18 follicular thyroid carcinomas (FTCs) and 48 papillary thyroid carcinomas (PTCs), and (3) leukocytes of two thyrocyte-depleted individuals treated for C-cell carcinoma of the thyroid. Expression of onfFN was additionally analysed by semiquantitative RT–PCR and by quantitative fluorescence-based real-time PCR. Tg and TSH-R expression was demonstrated not only in both athyroid individuals, but in all leukocyte subgroups tested, while hTERT was absent in resting CD4⁺ cells and only weakly expressed in the CD8⁺ group. CK 19 was notable in each leukocyte population except for resting CD14⁺, as well as for activated and resting CD19⁺ cells. All blood cell fractions proved negative for onfFN mRNA, whereas its presence in thyroid carcinoma was 78/98% (FTC/PTC). Threshold cycle values were calculated at: porphobilinogen deaminase (PBGD) =25.95±0.73 (FTC)/24.55±5.43 (PTC) (P=0.2878); onfFN=25.48±3.15 (FTC)/21.44±3.44 (PTC) (^*P=0.0001). Finally, onfFN transcripts were detected in blood samples of six out of nine patients with known DTC metastases, demonstrating a reliable assay functionality. We propose that real-time RT–PCR of onfFN mRNA is superior to other markers in monitoring minimal residual disease in DTC with regard to both assay sensitivity and specificity.

Ectopic expression of the CRF-binding protein: minor impact on HPA axis regulation but induction of sexually dimorphic weight gain

Corticotrophin-releasing factor (CRF) and urocortin possess a high-affinity binding protein. Although the CRF binding protein (BP) can sequester these ligands and inhibit their activity, the endogenous activity of this protein is not understood. Therefore, transgenic mouse lines that over-express the CRF-BP were created. The transgene was constructed by ligating rat CRF-BP cDNA (1.1 kb) between a mouse metallothionein-I promoter (1.8 kb) and a nonfunctional human growth hormone gene sequence (2.1 kb) in a modified pBR322 plasmid and microinjecting the transgene into C57BL/6 x SJL hybrid ova. The transgene was expressed in 50% in both male and female progeny. All transgenic lines were maintained by crossing transgenic animals with wild-type C57BL/6 mates. Reverse-transcriptase (RT) PCR of the CRF-BP transgene showed that it is widely expressed not only in the brain and pituitary, but also peripheral tissues including the liver, kidney and spleen. Transgenic animals of both sexes showed significant increases in weight gain as established by analysis of variance; however, the weight gain profiles for each sex were distinct. High levels of circulating CRF-BP were detected in the transgenic animals, but the basal ACTH and corticosterone levels were not significantly decreased compared to wild-type littermates. The hypothalamopituitary-adrenal (HPA) axis was stimulated by systemic inflammation induced with lipopolysaccharide (LPS). An expected increase in transgene expression was observed and was accompanied by a significant attenuation of ACTH secretion at 3 h after LPS injection in the transgenic males but not the females. These data suggest that HPA axis regulation is significantly affected only with very high circulating levels of CRF-BP. Moreover, this work supports previous studies that implicate CRF and urocortin in the regulation of appetite and the binding protein expression may play a sexually dimorphic role in regulating this and other responses.

Corticotropin releasing factor (CRF) binding protein: a novel regulator of CRF and related peptides

A 37-kDa corticotropin releasing factor (CRF) binding protein (CRF-BP) was purified from human plasma by repeated affinity purification and subsequently sequenced and cloned. The human and rat CRF-BP cDNAs encode proteins of 322 amino acids with one putative signal sequence, one N-glycosylation site, and 10 conserved cysteines. Human CRF-BP binds human CRF with high affinity but has low affinity for the ovine peptide. In contrast, sheep CRF-BP binds human and ovine CRF with high affinity. The CRF-BP gene consists of seven exons and six introns and is located on chromosome 13 and loci 5q of the mouse and human genomes, respectively. CRF-BP inhibits the adrenocorticotrophic hormone (ACTH) releasing properties of CRF in vitro. CRF-BP dimerizes after binding CRF and clears the peptide from blood. This clearance mechanism protects the maternal pituitary gland from elevated plasma CRF levels found during the third trimester of human pregnancy. CRF-BP is expressed in the brains of all species so far tested but is uniquely expressed in human liver and placenta. In brain, CRF-BP is membrane associated and is predominantly expressed in the cerebral cortex and subcortical limbic structures. In some brain areas CRF-BP colocalizes with CRF and CRF receptors. The protein is also present in pituitary corticotropes, where it is under positive glucocorticoid control, and is likely to locally modulate CRF-induced ACTH secretion. The ligand requirements of the CRF receptor and the CRF-BP can be distinguished in that central human CRF fragments, such as CRF (6-33) and CRF (9-33), have high affinity for CRF-BP but low affinity for the CRF receptor. The binding protein's ability to inhibit CRF-induced ACTH secretion can be reversed by CRF (6-33) and CRF (9-33), suggesting that ligand inhibitors may have utility in elevating free CRF levels in disease states associated with decreased CRF. Thus, by controlling the amount of free CRF which activates CRF receptors, it is likely that the CRF-BP is an important modulator of CRF both in the CNS and in the periphery.

Ligand requirements of the human corticotropin-releasing factor-binding protein

CRF-binding protein (CRF-BP), identified as a 37-kilodalton human serum protein, binds human (h) CRF (Kd = 0.17 +/- 0.01 nM) and blocks hCRF's ability to stimulate ACTH release by pituitary cells in vitro. The present study examines ligand requirements of CRF-BP by testing the affinity of recombinant CRF-BP for synthetic analogs of CRF and peptides in the CRF family. The relative affinities of various fragments of hCRF or related peptides for CRF-BP indicate that residues 9-28 are crucial for ligand binding. CRF-BP binds human/rat CRF and urotensin-I with high affinity, sauvagine with moderate affinity, and ovine (o) CRF with low affinity. The marked difference in the affinity of CRF-BP for oCRF (Ki = 1100 +/- 97 nM) compared to hCRF (Ki = 0.17 +/- 0.01 nM), when considered with the importance of the central domain, suggests that amino acids 22, 23, and/or 25 are critical for binding. Altering oCRF residues 22, 23, or 25 individually or collectively to match those of hCRF increases the affinity of CRF-BP for these ligands; [Ala22, Arg23, Glu25]oCRF, in which all three of these central amino acids are substituted by their hCRF counterparts, binds CRF-BP with an affinity equal to that of hCRF. CRF-BP has differential affinities for CRF receptor antagonists, binding alpha-helical CRF-(9-41) with high affinity and [D-Phe12, Nle21,38]hCRF-(12-41) with low affinity. Thus, the structural requirements for binding to CRF-BP can clearly be distinguished from those for CRF receptor recognition of both agonists and antagonists. Peptides such as hCRF-(9-33), with low biological activity but which retain high affinity for the binding protein, can competitively override the effects of CRF-BP to block CRF-induced ACTH secretion, raising the possibility that whereas endogenous CRF-BP serves to limit the distribution or duration of action of CRF, specific pharmacological inhibitors of the ligand-binding protein interaction might be used to therapeutically elevate free CRF levels.

Distribution of corticotropin-releasing factor receptor mRNA expression in the rat brain and pituitary

Corticotropin-releasing factor (CRF) is a major hypophysiotropic peptide regulating pituitary-adrenal response to stress, and it is also widely expressed in the central nervous system. The recent cloning of cDNAs encoding the human and rat CRF receptors has enabled us to map the distribution of cells expressing CRF receptor mRNA in rat brain and pituitary by in situ hybridization. Receptor expression in the forebrain is dominated by widespread signal throughout all areas of the neo-, olfactory, and hippocampal cortices. Other prominent sites of CRF receptor mRNA expression include subcortical limbic structures in the septal region and amygdala. In the diencephalon, low levels of expression are seen in a few discrete ventral thalamic and medial hypothalamic nuclei. CRF receptor expression in hypothalamic neurosecretory structures, including the paraventricular nucleus and median eminence, is generally low. In the brainstem, certain relay nuclei associated with the somatic (including trigeminal), auditory, vestibular, and visceral sensory systems, constituted prominent sites of CRF receptor mRNA expression. In addition, high levels of this transcript are present in the cerebellar cortex and deep nuclei, along with many precerebellar nuclei. In the pituitary, moderate levels of CRF receptor mRNA expression were detected throughout the intermediate lobe and in a subset of cells in the anterior lobe identified as corticotropes by concurrent immunolabeling. Overall, the central distribution of CRF receptor mRNA expression is similar to, though more expansive than, that of regions reported to bind CRF, and it shows limited overlap with loci expressing CRF-binding protein. Interestingly, CRF receptor mRNA is low or undetectable in several cell groups implicated as central sites of CRF action.

Assignment of disulfide bonds in corticotropin-releasing factor-binding protein

We have previously isolated, cloned, and characterized a protein that specifically binds and inactivates the peptide corticotropin-releasing factor. The integrity of the disulfide bonds in the binding protein is essential for this activity as reduction abolishes the protein's ability to bind corticotropin-releasing factor. The disulfide arrangement of the 10 cysteines present in the mature protein was established by analysis of proteolytically cleaved protein and sequence analysis of cystine containing fragments. A pattern is observed where each cysteine is connected to the next one in a sequential manner. Inspection of the genomic DNA encoding for this protein reveals that four of the domains defined by disulfide linkage coincide with four different exons.

Association of human corticotropin-releasing hormone to its binding protein in blood may trigger clearance of the complex

Late in the last trimester of human pregnancy, as plasma CRH levels rise, the concentration of circulating CRH-binding protein (CRH-BP) falls. We have investigated, using nonpregnant subjects, the hypothesis that CRH has a negative effect on plasma levels of CRH-BP. A specific RIA developed with the aid of recombinant binding protein has been used to measure CRH-BP. Subjects given iv infusions of human CRH for 10 h showed a sustained fall in plasma CRH-BP for the duration of the infusion. Intravenous bolus injection of human CRH produced a rapid reduction in CRH-BP levels to 54% of the basal value, whereas ovine CRH was without effect, even though both peptides are cleared from the plasma at similar rates and have similar effects on the pituitary-adrenal axis. The rapid clearance was concluded to be related to ligand affinity, as ovine CRH has a 200-fold lower affinity than human CRH for CRH-BP. We suggest that the rising levels of CRH are responsible for the reduction in CRH-BP concentrations observed in late pregnancy, and that this reduction is triggered by the binding of CRH-BP to its ligand.

Corticotropin-releasing factor-binding protein is produced by human placenta and intrauterine tissues

CRF circulates in high concentration in pregnant woman. It is produced by the placenta and the other intrauterine tissues (maternal decidua, amnion, and chorion). Recently, a CRF-binding protein (CRF-BP) has been identified and cloned. It binds the circulating CRF, reducing its biological action during pregnancy. Liver is the major source of CRF-BP. The aim of the present study was to evaluate whether human placenta and intrauterine tissues produce CRF-BP. The localization of mRNA and immune CRF-BP by in situ hybridization and immunohistochemistry, respectively, was performed. Antisense and sense riboprobes synthesized from a fragment of human CRF-BP cRNA and a specific rabbit anti-hCRF-BP serum was used. The syncytial layer of placental villi at term intensely expressed CRF-BP mRNA and immunoreactivity, whereas rare positively hybridized cells were observed within the cytotrophoblasts and mesenchymal cells. Large decidual cells, amniotic epithelial cells, and chorionic cytotrophoblast stained positively for CRF-BP mRNA and protein. Control sections collected from the same tissues failed to show any positive localization of sense strand cRNA probe and antiserum preadsorbed with immunogen. Finally, the addition of recombinant CRF-BP to human cultured placental cells significantly decreased CRF-induced ACTH release, with a dose-dependent effect. The present data show that local production of CRF-BP occurs in human trophoblast and intrauterine tissues and may represent one of the major mechanisms used by targets tissues to control CRF activity during pregnancy.

Cloning and structure of the human corticotrophin releasing factor-binding protein gene (CRHBP)

The human CRF-binding protein gene has been cloned and mapped to the distal region of chromosome 13 and loci 5q in the mouse and human genomes, respectively. The gene consists of 7 exons and 6 introns. The mature protein has 10 cysteines and 5 tandem disulfide bridges 4 of which are contained within exons 3, 5, 6, and 7. One bridge is shared by exons 3 and 4. The signal peptide and the first 3 amino acids of the mature protein were coded for by an extreme 5' exon. Primer extension analyses revealed the transcriptional initiation site to be located 32 bp downstream from a consensus TATA box. The promoter sequence contained a number of putative promoter elements including an AP-1 site, three ER-half sites, the immunoglobulin enhancer elements NF-kappa B and INF-1, and the liver-specific enhancers LFA1 and LFB1.

Corticotropin releasing hormone-binding protein (CRH-BP): plasma levels decrease during the third trimester of normal human pregnancy

In pregnancy, maternal plasma corticotropin releasing hormone (CRH) concentrations rise substantially in the third trimester and fall rapidly post-partum. A binding protein (BP) specific for CRH exists in the human circulation which inactivates CRH, thus possibly explaining why maternal ACTH does not rise outside normal limits throughout gestation. We here describe the measurement of CRH-BP directly in plasma during human pregnancy using a radioimmunoassay that is not affected by the presence of the high plasma levels of CRH that occur at this time. In 119 healthy non-pregnant individuals, mean CRH-BP levels were 4.46 nmol/L +/- 1.0 (SD), with a wide range of 1.81-7.24 nmol/L. Plasma CRH-BP in 34 pregnant women randomly sampled during the first and second trimesters also averaged 4.46 nmol/L +/- 1.54, with individual values ranging from 1.59-7.51 nmol/L and there was no correlation of CRH-BP levels with gestational age. In a group of 14 women sampled sequentially throughout the third trimester, plasma CRH-BP averaged 4.56 nmol/L +/- 1.70 at 30-35 weeks gestation and fell dramatically to 1.84 nmol/L +/- 0.43 at weeks 38-40 (P < 0.001). The post partum recovery in CRH-BP levels occurred within 48 hours of delivery. These results indicate that there is an increase in the availability of free, potentially bioactive CRH at term to stimulate the release of ACTH from the maternal pituitary and/or to act at a peripheral, non-pituitary CRH receptor(s).

The central distribution of a corticotropin-releasing factor (CRF)-binding protein predicts multiple sites and modes of interaction with CRF

In recent studies to clone and characterize genes coding for the corticotropin-releasing factor-binding protein (CRF-BP), analysis of the tissue distribution of the CRF-BP gene indicated a high level of expression in the rat brain. We have now characterized by immunohistochemical and hybridization histochemical means the cellular localization of CRF-BP protein and mRNA expression, respectively. Results from both approaches converged to indicate that CRF-BP is expressed predominantly in the cerebral cortex, including all major archi-, paleo-, and neocortical fields. Other prominent sites of mRNA and protein expression include subcortical limbic system structures (amygdala, bed nucleus of the stria terminalis), sensory relays associated with the auditory, olfactory, vestibular, and trigeminal systems, severe raphe nuclei, and a number of cell groups in the brainstem reticular core. Expression in the hypothalamus appears largely limited to the ventral premammillary and dorsomedial nuclei; only isolated CRF-BP-stained cells are apparent in neurosecretory cell groups. Dual immunostaining for CRF and CRF-BP revealed a partial colocalization in some of these regions. In addition, prominent CRF-BP-stained terminal fields have been identified in association with CRF-expressing cell groups in circumscribed hypothalamic and limbic structures. In the anterior pituitary, CRF-BP mRNA and immunoreactivity were colocalized with corticotropin-immunoreactivity in a majority of corticotropes. Thus, CRF-BP could serve to modify the actions of CRF by intra- and intercellular mechanisms, in CRF-related pathways in the central nervous system and pituitary.

Cloning and characterization of the cDNAs for human and rat corticotropin releasing factor-binding proteins

Corticotropin-releasing factor (CRF), is a potent stimulator of synthesis and secretion of preopiomelanocortin-derived peptides. Although CRF concentrations in the human peripheral circulation are normally low, they increase throughout pregnancy and fall rapidly after parturition. Maternal plasma CRF probably originates from the placenta, which responds to the bioactive peptide and produces the peptide and its messenger RNA. Even though CRF concentrations in late gestational maternal plasma are similar to those in rat hypothalamic portal blood and to those that can stimulate release of adrenocorticotropic hormone (ACTH) in vitro, maternal plasma ACTH concentrations increase only slightly with advancing gestation and remain within the normal range. Several groups have now reported the existence of a CRF-binding protein in human plasma which inactivates CRF and which has been proposed to prevent inappropriate pituitary-adrenal stimulation in pregnancy. The binding protein was recently purified from human plasma. We have now isolated and partially sequenced the binding protein, allowing us to clone and characterize its complementary DNA from human liver and rat brain. Expression of the cDNAs for human and rat binding protein in COS7 cells showed that these proteins bind CRF with the same affinity as the native human protein. Both rat and human recombinant binding proteins inhibit CRF binding to a CRF antibody and inhibit CRF-induced ACTH release by pituitary cells in vitro.

Inhibition of somatotroph growth and growth hormone biosynthesis by activin in vitro

Activin-A, a homodimeric protein composed of two inhibin beta A-subunits, was first isolated from gonadal fluids based upon its ability to stimulate FSH secretion and biosynthesis, but was also observed to suppress GH secretion. The present report describes the effects of activin on the biosynthesis of GH and the proliferation of pituitary somatotrophs. In pituitary cells cultured in the presence of 0.7 nM activin for 3 days, GH secretion was decreased by 50% compared to the control value. Inhibition of GH biosynthesis, measured by quantitative immunoprecipitation of [35S]methionine-labeled cells, could be observed after 24 h of activin treatment, and maximal (70%) inhibition of GH biosynthesis was observed after 3 days. Activin inhibited basal as well as GH-releasing factor (GRF)-, glucocorticoid-, and thyroid hormone-stimulated GH biosynthesis. Inhibin, which is known to reverse the effect of activin on FSH secretion, did not reverse the effect of activin on GH biosynthesis. Treatment of somatotrophs with activin for 3 days completely inhibited the growth-promoting effect of GRF on somatotrophs. However, no effect of activin on GRF-stimulated expression of the c-fos protooncogene was observed. These data demonstrate that activin, in addition to its stimulatory effect on FSH secretion, is able to inhibit both expression of GH and growth of somatotropic cells.

Effects of growth and insulin treatment on the levels of insulin receptors and their mRNA in Hep G2 cells

We have studied the variations in the number of insulin receptor and insulin receptor mRNA levels in (Hep G2) cells in response to growth and insulin treatment. The levels of insulin receptors are relatively low in growing cells. After approximately 5 days in culture, if cells are not refed they cease to divide and the number of receptors/cell increases, reaching 4 times the initial values by the 9th day. Refeeding the cells completely prevented both growth arrest and the increase in insulin receptor number. Insulin added daily to cells at 0.33 microM caused receptor down-regulation but did not prevent a 3-fold increase in binding with growth arrest. Pulse-chase studies of metabolically labeled ([35S]methionine) cells showed that the receptor degradation rate (apparent t 1/2, 18-20 h) was comparable in rapidly growing versus growth-arrested cells. The increased receptor level in non-refed cells is not due to generation of a soluble factor by confluent cells, nor is it caused by depletion of insulin, glucose, or insulin-like growth factor I from the culture medium. The levels of insulin receptor mRNA measured on Northern blots increased in growth-arrested cells in parallel to the increase in receptor number. The mRNA value begins to increase from the 3rd day in culture and by the 9th day reaches a level 6.0 times that on the 3rd day. Chronic insulin-induced receptor down-regulation did not alter insulin receptor mRNA levels at any time point studied. These data demonstrate that the increase in insulin receptor number/cell in growth-arrested cells is paralleled by an increase in insulin receptor mRNA content with no change in the receptor degradation rates. This suggests that the increase in the number of insulin receptors is due to enhanced receptor synthesis due to increased receptor mRNA content. Conversely, down-regulation of the insulin receptor does not affect the level of insulin receptor mRNA and thus must be due to increased receptor degradation.

The John Henryism and Framingham type A scales. Measurement properties in elderly blacks and whites

In 1984-1985, the authors interviewed 1,017 participants in the Charleston Heart Study in Charleston County, South Carolina to investigate the measurement properties of the Framingham Type A Scale in elderly blacks and whites and those of the John Henryism Scale for Active Coping, which was originally designed for use in black populations. They conclude that the Framingham Type A and John Henryism scales do in fact measure two quite different behavior patterns, and do have different correlates in elderly blacks and whites. The results are of particular interest since the Charleston Heart Study sample includes an oversampling of high socioeconomic status black males (n = 69). In this respect, it is unique among long-term cardiovascular studies and provides the opportunity to estimate separate race and socioeconomic status effects, as well as to examine their interaction.