Nephrology Nurses: Essential Professionals in Sustainable Kidney Care

Purpose

The increasing frequency of extreme climate events underscores the need for urgent action on climate change. The health care system contributes 4.6% of greenhouse gas emissions (GHGs) in Canada; thus, it is a major contributor to the country's carbon footprint. Kidney care in particular can involve high amounts of waste (eg, plastic and consumable waste associated with dialysis, transportation, emissions, energy, and water consumption). Therefore, sustainability initiatives within the health care system, and especially in the context of kidney care, have great potential to make a positive impact on planetary health. Here, we outline ways in which nephrology nurses can expand our duty of care to the environment and incorporate sustainability into our work.

Sources of information

A small advisory group of nephrology nurses in partnership with the Canadian Association of Nurses for the Environment (CANE) assessed ways that sustainable practices can be incorporated into nephrology nursing. Drawing on the Planetary Health Care model used by the Canadian Society of Nephrology: Sustainable Nephrology Action Planning (SNAP) committee, we assessed how the model could be adapted in the context of kidney care using 3 main actionable themes in their work: reducing the demand for health services, matching the supply of health services with demand, and reducing emissions from the supply of health services. We also reviewed and selected real-world examples of initiatives pursued by colleagues.

Key findings

Through this established framework, we provide recommendations and case examples for nephrology nurses to expand our duty of care to the environment. We describe nursing-led strategies used in Canada to improve environmental sustainability in kidney programs and consider their applicability to other renal programs. In 1 case example, we show how a simple nurse-led initiative at a single dialysis clinic can lower plastic waste and associated costs by $2042.59 per year. More broadly, we provide recommendations and actions for nephrology nurses to improve environmental sustainability in kidney care.

Limitations

Nurses in Canada have many responsibilities within limited timeframes, making it essential to choose sustainable practices that do not exacerbate burnout and high workloads. For sustainable practices to be successful, nurses must integrate them into their existing workflows.

Proteolysis Targeting Chimeras (PROTACs): A Perspective on Integral Membrane Protein Degradation

Targeted protein degradation (TPD) is a promising therapeutic modality to modulate protein levels and its application promises to reduce the "undruggable" proteome. Among TPD strategies, Proteolysis TArgeting Chimera (PROTAC) technology has shown a tremendous potential with attractive advantages when compared to the inhibition of the same target. While PROTAC technology has had a significant impact in scientific research, its application to degrade integral membrane proteins (IMPs) is still in its beginnings. Among the 15 compounds having entered clinical trials by the end of 2021, only two targets are membrane-associated proteins. In this review we are discussing the potential reasons which may underlie this, and we are presenting new tools that have been recently developed to solve these limitations and to empower the use of PROTACs to target IMPs.

Impact of maternal risk factors on the structure and function of the heart in newborns

Introduction

Maternal factors such as smoking during pregnancy, advanced age, and obesity are associated with increased risk of complex congenital heart defects in the offspring. It is unknown whether maternal risk factors may also cause subtle abnormalities in cardiac structure and function.

Purpose

To investigate whether the following maternal factors: advanced age, high body mass index (BMI), and smoking during pregnancy are associated with changes in left ventricle (LV) dimensions and systolic function in the newborn child.

Methods

Data was obtained as part of a population-based cohort study with prenatal inclusion and postnatal transthoracic echocardiography (TTE) of newborns within 60 days of birth. The TTE protocol included measurements of: Interventricular septal thickness at end-diastole (IVSd), LV posterior wall thickness at end-diastole (LVPWd), LV internal diameter at end-diastole (LVIDd) and LV internal diameter at end-systole (LVIDs). Fractional shortening (FS) was calculated by use of Teicholz's formula.

Children of mothers with data available on age, BMI, and smoking status, respectively, were divided into the following groups depending on whether their mothers were: of young age <25 years, 25–29 years, 30–34 years (reference group), 35–39 years, and advanced age ≥40 years; underweight BMI <18.5, normal range BMI 18.5–24.9 (reference group), preobese BMI 25–29.9, and obese BMI ≥30; smoking or nonsmoking (reference group).

Associations between different groups with each maternal risk factor and newborn LV parameters were analysed using a multiple linear regression model.

Results

Children of mothers with advanced age at the time of childbirth (n=1,411) had significantly smaller LVIDd and LVIDs (Table 1) compared to children of mothers in their early thirties (n=10,045). Children of preobese (n=4,707) and obese mothers (n=2,138) had significantly smaller LVIDd and LVIDs than children of mothers in the normal BMI range (n=17,654). Children of mothers who smoked during pregnancy (n=808) had significantly larger LVPWd than children of non-smoking mothers (n=24,072). A significant difference in FS was only seen in children of obese mothers.

Subanalyses of the quantity of maternal smoking (available data in n=548 [67.8%] of mothers who smoked during pregnancy) showed that children of heavy smoking mothers (≥15 cigarettes/day, n=101), had significantly thicker IVSd and LVPWd compared with children of nonsmoking mothers, whereas no significant effect was identified in newborns of mothers smoking less than 15 cigarettes per day (Table 2).

Conclusions

Systematic population-based echocardiography of newborns showed that an increased maternal BMI and maternal age above 40 years were associated with smaller LV cavity dimensions in the offspring and that heavy smoking during pregnancy was associated with increased LV myocardial thickness. FS was only affected in children of obese mothers. The long-term effects of these novel findings are unknown.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Herlev-Gentofte Hospital Internal Funding for Cardiological Research andThe Novo Nordisk Foundation

The experience of using prompting technology from the perspective of people with Dementia and their primary carers

OBJECTIVES

People who are living with dementia typically experience difficulties in completing multi-step, everyday tasks. However, digital technology such as touchscreen tablets provide a means of delivering concise personalised prompts that combine audio, text and pictures. This study was one component of a broader, mixed methods study that tested how an application (app) -based prompter running on a touchscreen tablet computer could support everyday activities in individuals with mild to moderate dementia. In this study we set out to understand the experiences of people living with dementia and their primary carer in using the prompter over a four-week period.

METHOD

We collected qualitative data using semi-structured interviews from 26 dyads, composed of a person living with dementia and their carer. Dyads were interviewed at the start and end of this period. Transcripts were then analysed using thematic analysis.

RESULTS

The study identified three overarching themes related to: participants' attitudes towards the technology; their judgements about how useful the prompter would be; and the emotional impact of using it.

CONCLUSION

Consistent with the Technology Acceptance Model, carers and participants were influenced by their approaches to technology and determined the usefulness of the prompter according to whether it worked for them and fitted into their routines. In addition, participants' decisions about using the prompter were also determined by the extent to which doing so would impact on their self-identity.

Small-molecule modulation of p53 protein-protein interactions

Small-molecule modulation of protein-protein interactions (PPIs) is a very promising but also challenging area in drug discovery. The tumor suppressor protein p53 is one of the most frequently altered proteins in human cancers, making it an attractive target in oncology. 14-3-3 proteins have been shown to bind to and positively regulate p53 activity by protecting it from MDM2-dependent degradation or activating its DNA binding affinity. PPIs can be modulated by inhibiting or stabilizing specific interactions by small molecules. Whereas inhibition has been widely explored by the pharmaceutical industry and academia, the opposite strategy of stabilizing PPIs still remains relatively underexploited. This is rather interesting considering the number of natural compounds like rapamycin, forskolin and fusicoccin that exert their activity by stabilizing specific PPIs. In this review, we give an overview of 14-3-3 interactions with p53, explain isoform specific stabilization of the tumor suppressor protein, explore the approach of stabilizing the 14-3-3σ-p53 complex and summarize some promising small molecules inhibiting the p53-MDM2 protein-protein interaction.

Spontaneous closure of ventricular septal defects in newborns the first year of life

Background

Ventricular septal defect (VSD) is one of the most common congenital heart defects. Some VSDs close spontaneously while persistence of the VSD may result in heart failure and, at long term, irreversible pulmonary hypertension. Consequently, identification of factors associated with spontaneous closure are important to ensure relevant clinical follow up of those at risk of a persistent VSD.

Purpose

We aimed to assess the rate of spontaneous closure in a population-based cohort of newborns with VSD and to identify significant predictors for spontaneous closure.

Methods

The study is part of a large-scale population-based study, focusing on cardiac structure and function, including newborns born from 1st April 2016 to 31st October 2018. Newborns with a VSDs at baseline were followed with echocardiography at 3, 6 and 12 months (+30 days) of age. Cox proportional hazard model was used to determine significant predictors of spontaneous closure

Results

Based on echocardiographies of 25.750 newborn, 850 newborns (3.3%) with a VSD were identified. The majority of newborns with VSDs were born at term (88.7%) and the mean age at inclusion was 11.7±8.1 days. VSDs were more frequent in females (57.1%, p<0.001). Of all VSDs, 787l (92.6%) were of a muscular type, 60 (7.0%) of perimembranous type and 3 (0.4%) were of subarterial type. Multiple VSDs were found in 98 (11.5%) cases and all were of a muscular type. Muscular VSDs were significantly smaller than perimembranous VSDs (1.9±0.7 mm vs. 3.7±1.8 mm, p<0.0001). During the follow up period, seven (0.8%) children underwent surgical repair: five (5 of 56) children with perimembranous VSDs and two (two of three) children with subarterial VSDs. Follow-up was complete in 89.4% of all children. After one year 82.6% (601 of 727) VSDs had closed spontaneously. The prevalence of VSD in one-year old children was thus 0.5%. The majority of VSD closed spontaneously during the first 6 months of life (57.6% (419/727)). Muscular VSDs showed significantly higher rate of spontaneous closure compared with perimembranous VSDs (86.9% (582 /670) vs. 46.2% (25/54), p=0.0001) during the first year of life. No subarterial VSDs closed spontaneously during follow-up. Muscular type (p=0.002), size (p<0.001) and presence of one VSD as opposed to multiple (p<0.0025) were associated to spontaneous closure. Sex did not significantly influence spontaneous closure rate (p=0.65).

Conclusion

In a population study including more than 25,000 newborns we found that the vast majority, i.e. almost 9/10 of all VSDs, closed spontaneously during the first year of life, ultimately resulting in a prevalence of VSD in one-year old children of 0.5%. The identified factors associated with spontaneous closure – anatomical location, size and presence of multiple VSDs are of use for future management of VSDs in newborns.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): The Danish Heart Foundation

Association between maternal diabetes and cardiac left ventricular structure and function in the neonate: a study from the Copenhagen Baby Heart Study

Background

Prenatal exposure to maternal diabetes has been associated with increased risk of congenital heart defects.

Purpose

To evaluate whether maternal diabetes is associated with more subtle morphological and functional cardiac changes in neonates without congenital heart defects.

Methods

We included 17,869 newborns sampled from the Copenhagen Baby Heart Study, all of whom underwent transthoracic echocardiography within 30 days of delivery. We investigated the association between exposure to maternal diabetes (pre-existing diabetes [type 1 or type 2 diabetes] or gestational diabetes [GDM]) and the neonates' echocardiographic indices of left ventricular structure (left posterior wall thickness in end-diastole [LVPWd], interventricular septum thickness in end-diastole [IVSd], left ventricular internal diameter in end-systole [LVIDs] and end-diastole [LVIDd]), systolic function (fractional shortening [FS], stroke volume [SV]) and diastolic function (mitral valve peak early and atrial filling velocities, deceleration time of early filling, and E/A-ratio), using linear and logistic regression. Models were adjusted for maternal age, infant sex, infant birth weight for gestational age and gestational age in days. In additional analyses, we evaluated the relationship between HbA1C levels in first and third trimester and left ventricular structure and function.

Results

We found that infants exposed to pre-existing maternal diabetes (n=x) had, on average, a thicker LVPWd (mean difference 0.12 mm [95% CI: 0.06–0.19]), a smaller LVIDs (−0.27 mm [95% CI: −0.46, −0.07]) and LVIDd (−0.43 mm [95% CI: −0.66, −0.19]), and decreased SV (−0.50 ml [95% CI: −0.77, −0.23]). We found no significant differences in IVSd, FS, and measures of diastolic function for infants exposed to pre-existing maternal diabetes compared with infants not exposed to diabetes. Infants exposed to GDM (n=) also had thicker LVPWd (0.06 mm [95% CI: −0.28, −0.01]) and smaller LVIDs (−0.15 mm [95% CI: −0.28, −0.01]); however, on average, IVSd, LVIDd, and measures of systolic and diastolic function did not differ for infants born to mothers with and without GDM. We observed no consistent association between HbA1C levels measured early and late in pregnancy in mothers with diabetes and indices of left ventricular structure and function.

Conclusion

In conclusion, we found that exposure to maternal pre-existing diabetes, and to a lesser degree GDM, was associated with changes in neonatal left ventricular structure and function, including a thicker left ventricular posterior wall, smaller left ventricular internal diameters, and lower stroke volumes.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Rigsbospitalet Research Foundation

Structural analysis of the LDL receptor-interacting FERM domain in the E3 ubiquitin ligase IDOL reveals an obscured substrate-binding site

Hepatic abundance of the low-density lipoprotein receptor (LDLR) is a critical determinant of circulating plasma LDL cholesterol levels and hence development of coronary artery disease. The sterol-responsive E3 ubiquitin ligase inducible degrader of the LDLR (IDOL) specifically promotes ubiquitination and subsequent lysosomal degradation of the LDLR and thus controls cellular LDL uptake. IDOL contains an extended N-terminal FERM (4.1 protein, ezrin, radixin, and moesin) domain, responsible for substrate recognition and plasma membrane association, and a second C-terminal RING domain, responsible for the E3 ligase activity and homodimerization. As IDOL is a putative lipid-lowering drug target, we investigated the molecular details of its substrate recognition. We produced and isolated full-length IDOL protein, which displayed high autoubiquitination activity. However, in vitro ubiquitination of its substrate, the intracellular tail of the LDLR, was low. To investigate the structural basis for this, we determined crystal structures of the extended FERM domain of IDOL and multiple conformations of its F3ab subdomain. These reveal the archetypal F1-F2-F3 trilobed FERM domain structure but show that the F3c subdomain orientation obscures the target-binding site. To substantiate this finding, we analyzed the full-length FERM domain and a series of truncated FERM constructs by small-angle X-ray scattering (SAXS). The scattering data support a compact and globular core FERM domain with a more flexible and extended C-terminal region. This flexibility may explain the low activity in vitro and suggests that IDOL may require activation for recognition of the LDLR.

Fragment-based Differential Targeting of PPI Stabilizer Interfaces

Stabilization of protein-protein interactions (PPIs) holds great potential for therapeutic agents, as illustrated by the successful drugs rapamycin and lenalidomide. However, how such interface-binding molecules can be created in a rational, bottom-up manner is a largely unanswered question. We report here how a fragment-based approach can be used to identify chemical starting points for the development of small-molecule stabilizers that differentiate between two different PPI interfaces of the adapter protein 14-3-3. The fragments discriminately bind to the interface of 14-3-3 with the recognition motif of either the tumor suppressor protein p53 or the oncogenic transcription factor TAZ. This X-ray crystallography driven study shows that the rim of the interface of individual 14-3-3 complexes can be targeted in a differential manner with fragments that represent promising starting points for the development of specific 14-3-3 PPI stabilizers.

Proteolysis-targeting chimeras in drug development: A safety perspective

Proteolysis-targeting chimeras are a new drug modality that exploits the endogenous ubiquitin proteasome system to degrade a protein of interest for therapeutic benefit. As the first-generation of proteolysis-targeting chimeras have now entered clinical trials for oncology indications, it is timely to consider the theoretical safety risks inherent with this modality which include off-target degradation, intracellular accumulation of natural substrates for the E3 ligases used in the ubiquitin proteasome system, proteasome saturation by ubiquitinated proteins, and liabilities associated with the "hook effect" of proteolysis-targeting chimeras This review describes in vitro and non-clinical in vivo data that provide mechanistic insight of these safety risks and approaches being used to mitigate these risks in the next generation of proteolysis-targeting chimera molecules to extend therapeutic applications beyond life-threatening diseases.

Adoption of a Turn Conformation Drives the Binding Affinity of p53 C-Terminal Domain Peptides to 14-3-3σ

The interaction between the adapter protein 14-3-3σ and transcription factor p53 is important for preserving the tumor-suppressor functions of p53 in the cell. A phosphorylated motif within the C-terminal domain (CTD) of p53 is key for binding to the amphipathic groove of 14-3-3. This motif is unique among 14-3-3 binding partners, and the precise dynamics of the interaction is not yet fully understood. Here, we investigate this interaction at the molecular level by analyzing the binding of different length p53 CTD peptides to 14-3-3σ using ITC, SPR, NMR, and MD simulations. We observed that the propensity of the p53 peptide to adopt turn-like conformation plays an important role in the binding to the 14-3-3σ protein. Our study contributes to elucidate the molecular mechanism of the 14-3-3-p53 binding and provides useful insight into how conformation properties of a ligand influence protein binding.

IDOL regulates systemic energy balance through control of neuronal VLDLR expression

Liver X receptors limit cellular lipid uptake by stimulating the transcription of Inducible Degrader of the LDL Receptor (IDOL), an E3 ubiquitin ligase that targets lipoprotein receptors for degradation. The function of IDOL in systemic metabolism is incompletely understood. Here we show that loss of IDOL in mice protects against the development of diet-induced obesity and metabolic dysfunction by altering food intake and thermogenesis. Unexpectedly, analysis of tissue-specific knockout mice revealed that IDOL affects energy balance, not through its actions in peripheral metabolic tissues (liver, adipose, endothelium, intestine, skeletal muscle), but by controlling lipoprotein receptor abundance in neurons. Single-cell RNA sequencing of the hypothalamus demonstrated that IDOL deletion altered gene expression linked to control of metabolism. Finally, we identify VLDLR rather than LDLR as the primary mediator of IDOL effects on energy balance. These studies identify a role for the neuronal IDOL-VLDLR pathway in metabolic homeostasis and diet-induced obesity.

A Comparative Study of Fluorescence Assays in Screening for BRD4

Fluorescence assay technologies are commonly used in high-throughput screening because of their sensitivity and ease of use. Different technologies have their characteristics and the rationale for choosing one over the other can differ between projects because of factors such as availability of reagents, assay performance, and cost. Another important factor to consider is the assay susceptibility to artifacts, which is almost as important as the ability of the assay to pick up active compounds. Spending time and money on false positives or missing the opportunity to build chemistry around false negatives is something that every drug project tries to avoid. We used a BET family Bromodomain, BRD4(1), to explore the outcome of a screening campaign using three fluorescent assay technologies as primary assays. A diverse 7,038 compound set was screened in fluorescence lifetime, fluorescence polarization, and homogeneous time-resolved fluorescence to look at primary hit rates, compound overlap, and hit confirmation rates. The results show a difference between the fluorescence assay technologies with three separate hit lists and some overlap. The confirmed hits from each assay were further evaluated for translation into cells (NanoBRET™). Most of the actives confirmed in cells originated from compounds that overlapped between the assays. In addition, a well-annotated set of compounds with undesirable mechanism of inhibition was screened against BRD4(1) to compare the ability to discriminate true hits from artifact compounds. The results indicate a difference between the assays in their ability to generate false positives and negatives.

Inhibition of low-density lipoprotein receptor degradation with a cyclic peptide that disrupts the homodimerization of IDOL E3 ubiquitin ligase

Cellular uptake of circulating cholesterol occurs via the low density lipoprotein receptor (LDLR). The E3 ubiquitin ligase IDOL is a mediator of LDLR degradation, with IDOL homodimerization thought to be required for its activity. To probe the possibility of modulating LDLR levels with an inhibitor of IDOL homodimerization, we screened a SICLOPPS library of 3.2 million cyclic peptides for compounds that disrupt this protein-protein interaction. We identified cyclo-CFFLYT as the lead inhibitor, and improved its activity through the incorporation of non-natural amino acids. The activity of the optimized cyclic peptide was assessed in hepatic cells, with a dose-dependent increase in LDLR levels observed in the presence of our IDOL homodimerization inhibitor.

Design of a Chemical Probe for the Bromodomain and Plant Homeodomain Finger-Containing (BRPF) Family of Proteins

The bromodomain and plant homeodomain finger-containing (BRPF) family are scaffolding proteins important for the recruitment of histone acetyltransferases of the MYST family to chromatin. Here, we describe NI-57 (16) as new pan-BRPF chemical probe of the bromodomain (BRD) of the BRPFs. Inhibitor 16 preferentially bound the BRD of BRPF1 and BRPF2 over BRPF3, whereas binding to BRD9 was weaker. Compound 16 has excellent selectivity over nonclass IV BRD proteins. Target engagement of BRPF1B and BRPF2 with 16 was demonstrated in nanoBRET and FRAP assays. The binding of 16 to BRPF1B was rationalized through an X-ray cocrystal structure determination, which showed a flipped binding orientation when compared to previous structures. We report studies that show 16 has functional activity in cellular assays by modulation of the phenotype at low micromolar concentrations in both cancer and inflammatory models. Pharmacokinetic data for 16 was generated in mouse with single dose administration showing favorable oral bioavailability.

The role of filaggrin mutations during pregnancy and postpartum: atopic dermatitis and genital skin diseases

Mutations in the epidermal filaggrin gene (FLG) are associated with skin barrier dysfunction (dry skin, less acidic skin, and fissured skin), and atopic dermatitis (AD) with a severe and persistent course. Because pregnancy and delivery further impairs normal skin barrier functions (immune suppression, mechanical stress), we studied the possible role of FLG mutations on the risk of AD flares, genital infections, and postpartum problems related to perineal trauma. FLG-genotyping was performed in a population-based sample of 1837 women interviewed in the 12th and 30th weeks of pregnancy and 6 months postpartum as part of the Danish National Birth Cohort study 1996-2002. We found that FLG mutations also influence pregnancy-related skin disease; thus, women with FLG mutations had an increased risk of AD flares during pregnancy (OR 10.5, 95% CI 3.6-30.5) and of enduring postpartum physical problems linked to perineal trauma during delivery (OR 11.1, 95% CI 1.1-107.7).

Impact of Etanercept Therapy on Disease Activity and Health-Related Quality of Life in Moderate Rheumatoid Arthritis Patients Population from a National British Observational Cohort

OBJECTIVES

To describe a population with moderate rheumatoid arthritis (RA) before biologic initiation and assess change in disease status, health-related quality of life (HRQOL), and adverse events in etanercept (ETN)-treated patients.

METHODS

Data on adult patients with moderate RA (3.2 < Disease Activity Score in 28 Joints [DAS28] ≤ 5.1) were retrospectively analyzed from the British Society for Rheumatology Biologics Register comparing a nonbiologic-treated group (nBG) using at least one traditional disease-modifying antirheumatic drug to a biologic group (BG) treated with ETN. The HRQOL was assessed by using the Health Assessment Questionnaire disability index score. To mitigate confounding, we controlled for drivers of progression. Appropriate univariate, multivariate, and regression analyses were used.

RESULTS

A total of 1754 patients with RA were assessed (211 BG and 1543 nBG). Compared with the nBG, the BG tended toward higher disease activity, such as significantly higher tender joints and DAS28. The BG compared with the nBG had 1) a greater reduction in DAS28 and Health Assessment Questionnaire scores; 2) disease remission occurring more often (odds ratio = 2.7; P = 0.006); and 3) progression occurring in fewer patients (odds ratio = 0.3; P = 0.002). BG patients had a higher incidence of "other serious infection" and "other central nervous system-related events," with no significant differences in associated hospitalization rates or deaths.

CONCLUSIONS

Among patients with moderate RA from a clinical practice registry, ETN-treated patients had significantly higher disease activity at the time of biologic initiation but significantly reduced disease activity and better HRQOL after 6 months compared with nBG patients, although the possibility of unmeasured confounding remains. The ETN group reported significantly higher incidences of "other serious infections" and "other central nervous system-related events" without higher hospitalization rates.

Assessing HTS performance using BioAssay Ontology: screening and analysis of a bacterial phospho-N-acetylmuramoyl-pentapeptide translocase campaign

With the public availability of biochemical assays and screening data constantly increasing, new applications for data mining and method analysis are evolving in parallel. One example is BioAssay Ontology (BAO) for systematic classification of assays based on screening setup and metadata annotations. In this article we report a high-throughput screening (HTS) against phospho-N-acetylmuramoyl-pentapeptide translocase (MraY), an attractive antibacterial drug target involved in peptidoglycan synthesis. The screen resulted in novel chemistry identification using a fluorescence resonance energy transfer assay. To address a subset of the false positive hits, a frequent hitter analysis was performed using an approach in which MraY hits were compared with hits from similar assays, previously used for HTS. The MraY assay was annotated according to BAO and three internal reference assays, using a similar assay design and detection technology, were identified. Analyzing the assays retrospectively, it was clear that both MraY and the three reference assays all showed a high false positive rate in the primary HTS assays. In the case of MraY, false positives were efficiently identified by applying a method to correct for compound interference at the hit-confirmation stage. Frequent hitter analysis based on the three reference assays with similar assay method identified additional false actives in the primary MraY assay as frequent hitters. This article demonstrates how assays annotated using BAO terms can be used to identify closely related reference assays, and that analysis based on these assays clearly can provide useful data to influence assay design, technology, and screening strategy.

Association between disease activity and risk of serious infections in subjects with rheumatoid arthritis treated with etanercept or disease-modifying anti-rheumatic drugs

OBJECTIVES

To determine the risk of serious infection in patients with rheumatoid arthritis (RA) receiving etanercept (ETN) or disease-modifying anti-rheumatic drugs (DMARDs) and to identify factors that predict a higher risk.

METHODS

Five-year data from the British Society of Rheumatology Biologics Register (BSRBR), a prospective observational study of patients with active RA treated with ETN, were used. These data were compared with a cohort of patients receiving DMARDs with active RA.

RESULTS

Total follow-up was 19,964 patient-years (py; ETN, 14,381 py; DMARDs, 5583 py). Over the study period, 651 first-recorded serious infections were reported (ETN, 469 [39.9 per 1000 py]; DMARDs, 182 [35.0 per 1000 py]). Overall the risk of serious infection was similar for the 2 treatments; however, in the first 6 months of treatment the hazard ratio (HR) was higher in the ETN than the DMARD group (1.979; p=0.015). A linear association was observed between the serious infection rate and disease-activity score in 28 joints (DAS28) in patients from each treatment group and overall (DAS28 <4, 27.1 per 1000 py; DAS28 ≥8, 64.4 per 1000 py; 7.5% increase in serious infection for each unit increase of DAS28 score at baseline). In a time-dependent analysis, a DAS28 change of 1 unit during follow-up predicted a 27% increase in serious infection rates.

CONCLUSIONS

No significant increase in the risk of serious infection was observed with ETN versus DMARDs over the 5-year study; a linear relationship existed between the serious infection rate and disease activity, as measured by DAS28.

Making trans parents visible: Intersectionality of trans and parenting identities

This article explores the self-reported parenting challenges of 50 transgender parents based on an online survey of lesbian, gay, bisexual, and trans parents in the United States. Many trans parents transitioned after forming a family, whereas others had children after or even during transition. They coordinated their transition with parenting responsibilities, and carefully managed their visibility in parenting settings to protect their children. This analysis focuses on the challenges that trans parents faced at the intersection of their parenting and trans identities. Although trans parents share many of the concerns of cisgender parents, they also face unique challenges that must often be navigated without extensive support. Revealing these challenges increases trans parents’ visibility in society, and could help therapists and school administrators become more sensitive to the intersectional identities of trans people and the stressors unique to trans parenting.

The anticholinesterase activity of some antiadrenaline agents

The contractions of the isolated guinea-pig vas deferens in response to stimulation of the sympathetic hypogastric nerve were potentiated by low concentrations and inhibited by high concentrations of the antiadrenaline agents tolazoline, yohimbine, ergotamine, phenoxybenzamine and piperoxan. Eserine potentiated the contractions of the vas deferens produced by hypogastric nerve stimulation. The cholinesterase activity of an extract of vas deferens was decreased by the antiadrenaline agents. The potentiation of responses to sympathetic stimulation by antiadrenaline drugs, which also possess anticholinesterase activity, can be explained on the basis of a cholinergic sympathetic mechanism.

Fluorescently Labeled Analogues of Dofetilide as High-Affinity Fluorescence Polarization Ligands for the Human Ether-a-go-go-Related Gene (hERG) Channel

Novel fluorescent derivatives of dofetilide (1) have been synthesized. Analogues that feature a fluorescent probe attached through an aliphatic spacer to the central tertiary nitrogen of 1 have high affinity for the hERG channel, and affinity is dependent on both linker length and pendent dye. These variables have been optimized to generate Cy3B derivative 10e, which has hERG channel affinity equivalent to that of dofetilide. When bound to cell membranes expressing the hERG channel, 10e shows a robust increase in fluorescence polarization (FP) signal. In a FP binding assay using 10e as tracer ligand, Ki values for several known hERG channel blockers were measured and excellent agreement with the literature Ki values was observed over an affinity range of 2 nM to 3 muM. 10e blocks hERG channel current in electrophysiological patch clamp experiments, and computational docking experiments predict that the dofetilide core of 10e binds hERG channel in a conformation similar to that previously predicted for 1. These analogues enable high-throughput hERG channel binding assays that are rapid, economical, and predictive of test compounds' potential for prolonged QT liabilities.

Early evaluation of compound QT prolongation effects: A predictive 384-well fluorescence polarization binding assay for measuring hERG blockade

INTRODUCTION

A large number of drugs from a variety of pharmacological classes have been demonstrated to cause adverse effects on cardiac rhythm, including the life-threatening arrhythmia Torsades de Pointes. These side effects are often associated with prolongation of the QT interval and are mediated via blockade of the human ether-a-go-go related gene (hERG) encoded potassium channel. In order to manage this risk in the pharmaceutical industry it is desirable to evaluate QT prolongation as early as possible in the drug discovery process.

METHODS

Here we describe the development of a 384-well fluorescence polarization (FP) binding assay compatible with high-throughput assessment of compound blockade of the hERG channel during the lead optimisation process. To characterise the fluorescent ligand that was developed, competition binding studies, kinetic studies and electrophysiology studies were performed. Furthermore, to validate the assay as a key screening method a series of competition binding studies were performed and correlated with functional data obtained via patch-clamp.

RESULTS

Evaluation of the assay indicates that high quality data is obtained (Z'>0.6), that the K(i) values determined are equivalent to more traditional radiometric methods and that it is predictive for functional hERG blockade as assessed by patch clamp.

DISCUSSION

Whilst FP assays, utilizing a variety of fluors, have become well established for the evaluation of G-protein-coupled receptor (GPCRs) and kinase ligand interactions, this technique has not been applied widely to the study of ion channels. Therefore, this represents a novel assay format that is amenable to the evaluation of thousands of compounds per day. Whilst other assay formats have proven predictive or high throughput, this assay represents one of few that combines both attributes, moreover it represents the most cost effective assay, making it truly amenable to early assessment of hERG blockade.

Identification of a series of tricyclic natural products as potent broad-spectrum inhibitors of metallo-beta-lactamases

This work describes the discovery and characterization of a novel series of tricyclic natural product-derived metallo-beta-lactamase inhibitors. Natural product screening of the Bacillus cereus II enzyme identified an extract from a strain of Chaetomium funicola with inhibitory activity against metallo-beta-lactamases. SB236050, SB238569, and SB236049 were successfully extracted and purified from this extract. The most active of these compounds was SB238569, which possessed K(i) values of 79, 17, and 3.4 microM for the Bacillus cereus II, Pseudomonas aeruginosa IMP-1, and Bacteroides fragilis CfiA metallo-beta-lactamases, respectively, yet none of the compounds exhibited any inhibitory activity against the Stenotrophomonas maltophilia L-1 metallo-beta-lactamase (50% inhibitory concentration > 1,000 microM). The lack of activity against angiotensin-converting enzyme and serine beta-lactamases demonstrated the selective nature of these compounds. The crystal structure of SB236050 complexed in the active site of CfiA has been obtained to a resolution of 2.5 A. SB236050 exhibits key polar interactions with Lys184, Asn193, and His162 and a stacking interaction with the indole ring of Trp49 in the flap, which is in the closed conformation over the active site groove. SB236050 and SB238569 also demonstrate good antibacterial synergy with meropenem. Eight micrograms of SB236050 per ml gave rise to an eightfold drop in the MIC of meropenem for two clinical isolates of B. fragilis producing CfiA, making these strains sensitive to meropenem (MIC < or = 4 microg/ml). Consequently, this series of metallo-beta-lactamase inhibitors exhibit the most promising antibacterial synergy activity so far observed against organisms producing metallo-beta-lactamases.

Urinary cytokines for assessing inflammation in HIV-associated wasting

The relationship between cytokines and HIV-related weight loss has not been well established. Unlike most cytokines that are secreted in a paracrine manner, IL-6, sTNFR-II, and IL-1ra are readily detected in the systemic circulation and serve as markers of the inflammatory response. Twenty-four-hour urine concentrations of these proteins are believed to provide an integrative assessment of their systemic levels over the preceding hours. We sought to determine whether spot measurements of IL-6, sTNFR-II, and IL-1ra could be related to subsequent 24 h concentrations and prior weight loss. Eighteen subjects with severe wasting (average BMI=18+/-3 kg/m2with 19+/-13 kg of weight loss) and six HIV-negative healthy subjects were tested. Compared to values in controls, 24-h urinary concentrations of the three proteins adjusted for creatinine excreted were elevated in 44%, 89%, and 72% of patients, respectively. Twenty-four-hour concentrations were highly correlated with the spot concentrations (r=0.80, 0.87, 0.84, respectively, P<0.001). IL-1ra concentrations (24 h and spot) were correlated with weight loss in the previous 6 months, lifetime rate of weight loss and the 6 month rate of weight loss (spot: r=0.66, 0.73, 0.68, respectively, P< or =0.001). These data suggest that spot urinary collections can be used to estimate 24 h excretion rates. This strategy may be useful in assessing the inflammatory response in HIV-associated wasting.

SB-253514 and analogues; novel inhibitors of lipoprotein-associated phospholipase A2 produced by Pseudomonas fluorescens DSM 11579. I. Fermentation of producing strain, isolation and biological activity

Two new classes of inhibitors of LpPLA2 have been identified in fermentations of Pseudomonas fluorescens. The two structurally isomeric series differ in the geometry of closure of the bicyclic carbamate and comprise a range of compounds varying only in length of their lipophilic sidechain. The most abundant species were extracted from the cells and purified by silica and C18 chromatography. Members of the more stable class were shown to be potent and selective competitive inhibitors of LpPLA2.

A report system for PET assessment of myocardial viability

Coronary bypass surgery can improve the prognosis of patients with heart failure due to coronary artery disease. However, these patients have a high operative risk and should be operated on only if they have a sizeable amount of viable tissue (i.e. asynergic myocardium) that can recover contractile function following coronary revascularization. In the clinical setting, regional wall motion is usually evaluated by two-dimensional echocardiography, whereas retained metabolic activity assessed by positron emission tomography (PET) and 18F-fluorodeoxyglucose is a well-established means for the evaluation of myocardial viability. Unfortunately, the two-dimensional echocardiography and PET reports are often different, and this renders the matching of information difficult and the estimation of the risk-benefit ratio of the operation unreliable. In this paper, we present a report system for the evaluation of myocardial viability with PET. We divided the left ventricle into 16 segments following the proposal of the American Society of Echocardiography for wall motion analysis by two-dimensional echocardiography. Following this partition, three portions of the left ventricle are identified along the long axis: basal, mid and apical. Each plane of the basal and mid portions is automatically divided into six segments with the super-imposition of a radial divider over the short-axis images. Similarly, each plane of the apical portion is automatically divided, but into four segments. This partition of the left ventricle permits a precise match between the information on wall motion obtained with two-dimensional echocardiography and that on viability obtained with PET.

Transmural myocardial blood flow distribution in hypertrophic cardiomyopathy and effect of treatment

Verapamil alleviates symptoms in patients with hypertrophic cardiomyopathy (HCM), but the underlying mechanism of improvement remains speculative. Baseline and dipyridamole myocardial blood flow (MBF) were measured in 15 HCM patients (14 men, 42 +/- 10 years), before and after 4 weeks of verapamil SR 480 mg daily, using 15O labelled water the positron emission tomography (PET). Subendocardial (endo) and subepicardial (epi) MBF was measured in the septum (thickness 25.4 +/- 5.8 mm). Pre-treatment baseline whole heart MBF was 1.02 +/- 0.28 ml/min/g and 1.01 +/- 0.30 ml/min/g on treatment (p = ns). Dipyridamole MBF was 1.39 +/- 0.31 ml/min/g off treatment and 1.23 +/- 0.34 ml/min/g on treatment (p = ns). Coronary flow reserve (dipyridamole/resting MBF) was 1.45 +/- 0.52 and 1.30 +/- 0.51, respectively (p = ns). At baseline, the septal endo/epi MBF ratio was uniform off and on treatment (1.13 +/- 0.18 vs 1.18 +/- 0.21, p = ns). Before treatment, the endo/epi ratio following dipyridamole decreased to 0.93 +/- 0.24 (p < 0.01 vs baseline) and 5/15 (33%) patients had a ratio < 0.8 which would suggest subendocardial underperfusion. During treatment, the endo/epi ratio following dipyridamole was no more different from baseline (1.06 +/- 0.24, p = ns vs baseline) and 2/14 (14%) patients had an endo/epi < 0.8. PET can be successfully used to determine transmural MBF in vivo in patients with hypertrophied ventricles. Despite symptomatic improvement, high dose verapamil therapy does not increase total MBF in patients with HCM but may improve septal transmural MBF distribution during dipyridamole in some patients.

ATP-Citrate lyase as a target for hypolipidemic intervention. 2. Synthesis and evaluation of (3R,5S)-omega-substituted-3-carboxy-3, 5-dihydroxyalkanoic acids and their gamma-lactone prodrugs as inhibitors of the enzyme in vitro and in vivo

A series of (3R,5S)-omega-substituted-3-carboxy-3, 5-dihydroxyalkanoic acids have been synthesized and evaluated as inhibitors of the recombinant human form of ATP-citrate lyase. The best of these have Ki's in the 200-1000 nM range. As the corresponding thermodynamically favored gamma-lactone prodrugs, a number of compounds are able to inhibit cholesterol and fatty acid synthesis in HepG2 cells and reduce plasma triglyceride levels in vivo. The best of these, compound 77, is able to induce clear hypocholesterolemic and hypotriglyceridaemic responses when administered orally to rat and dog. These results provide evidence to support the hypothesis that compounds which inhibit ATP-citrate lyase have the potential to be a novel class of hypolipidemic agent, which possess combined hypocholesterolemic and hypotriglyceridemic activities.

The role of ATP citrate-lyase in the metabolic regulation of plasma lipids. Hypolipidaemic effects of SB-204990, a lactone prodrug of the potent ATP citrate-lyase inhibitor SB-201076

ATP citrate (pro-S)-lyase (EC 4.1.3.8), a cytosolic enzyme that generates acetyl-CoA for cholesterol and fatty acid synthesis de novo, is a potential target for hypolipidaemic intervention. Here we describe the biological effects of the inhibition of ATP citrate-lyase on lipid metabolism in Hep G2 cells, and plasma lipids in rats and dogs, by using SB-204990, the cell-penetrant gamma-lactone prodrug of the potent ATP citrate-lyase inhibitor SB-201076 (Ki=1 microM). Consistent with an important role of ATP citrate-lyase in the supply of acetyl-CoA units for lipid synthesis de novo, SB-204990 inhibited cholesterol synthesis and fatty acid synthesis in Hep G2 cells (dose-related inhibition of up to 91% and 82% respectively) and rats (76% and 39% respectively). SB-204990, when administered orally to rats, was absorbed into the systemic circulation; pharmacologically relevant concentrations of SB-201076 were recovered in the liver. When administered in the diet (0.05-0. 25%, w/w) for 1 week, SB-204990 caused a dose-related decrease in plasma cholesterol (by up to 46%) and triglyceride levels (by up to 80%) in rats. This hypolipidaemic effect could be explained, at least in part, by a decrease (up to 48%) in hepatic very-low-density lipoprotein (VLDL) production as measured by the accumulation of VLDL in plasma after injection of Triton WR-1339. SB-204990 (25 mg/kg per day) also decreased plasma cholesterol levels (by up to 23%) and triglyceride levels (by up to 38%) in the dog, preferentially decreasing low-density lipoprotein compared with high-density lipoprotein cholesterol levels. Overall these results are consistent with the concept that ATP citrate-lyase is an important enzyme in controlling substrate supply for lipid synthesis de novo and a potential enzyme target for hypolipidaemic intervention.

Characterization of pituitary adenylate cyclase-activating polypeptide 38 (PACAP38)-, PACAP27-, and vasoactive intestinal peptide-stimulated responses in N1E-115 neuroblastoma cells

In this study, the effects of three related peptides, pituitary adenylate cyclase-activating polypeptide 38 (PACAP38), PACAP27, and vasoactive intestinal peptide (VIP), on cyclic AMP (cAMP) accumulation and intracellular Ca2+ concentration ([Ca2+]i) were compared in N1E-115 cells. PACAP38 and PACAP27 stimulated cAMP accumulation up to 60-fold with EC50 values of 0.54 and 0.067 nM, respectively. The effect of VIP on cAMP accumulation was less potent. The binding of 125I-PACAP27 to intact cells was inhibited by PACAP38 and PACAP27 (IC50 values of 0.44 and 0.55 nM, respectively) but not by VIP. In fura-2-loaded cells, both PACAP38 and PACAP27 increased [Ca2+]i with EC50 values around 10 nM. The interactions of these three peptides with ionomycin, a Ca2+ ionophore, and 4 beta-phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C, were also determined. Ionomycin increased the cAMP accumulation caused by all three peptides. With low concentrations of PACAP38 or PACAP27, the effect of PMA was inhibitory, whereas at higher concentrations of PACAP (> 1 nM), the effect of PMA was stimulatory. Similar to other agents that elevate cAMP, PACAP38 was an effective stimulator of neurite outgrowth. These results show that (a) PACAP27 and PACAP38 stimulate cAMP accumulation and increase [Ca2+]i through the type I PACAP receptors in N1E-115 cells, (b) ionomycin enhances cAMP accumulation by all three peptides, and (c) activation of protein kinase C has a dose-dependent stimulatory or inhibitory effect on the PACAP38- or PACAP27-stimulated cAMP accumulation.

Health-related quality of life of adults surviving malignancies in childhood

While sophisticated data on specific problems are available, very little is known about the overall quality of life of long-term survivors of malignancies in childhood. We used a previously validated 15-dimensional questionnaire to examine the perceived health-related quality of life of 168 survivors, currently aged 16-35 years, who had been treated for a malignancy at a single institution between 1961 and 1993. All had been off therapy for at least 1 year (median, 12 years). In statistical terms, the quality of life score of the survivors was significantly better than that of 129 normal controls [0.966 versus 0.941 (theoretical maximum 1), respectively; P < 0.001]; however, a difference of this magnitude is most likely not clinically significant. There were no associations between original diagnosis and present quality of life, but the numbers in each diagnostic group were small. The survivors reported significantly better levels of vitality, distress, depression, discomfort, elimination and sleeping dimensions than the controls. Although we are presently not able to identify all the contributing factors, we speculate that the high perceived quality of life of long-term survivors of childhood malignancies is at least in part a consequence of denial mechanisms which compensate or even overcompensate the objectively measurable late effects of childhood cancer.

Myocardial beta-adrenoceptor density and plasma catecholamines in syndrome X

Recent research has cast doubt on the ischemic hypothesis of etiology of syndrome X (anginal pain, ischemic-like changes in the stress electrocardiogram, but normal coronary arteriogram). Abnormalities of pain perception have been shown and abnormal sympathetic nervous system activation has also been implicated. The aim of this study was to test the hypothesis that downregulation of myocardial beta adrenoceptors is demonstrable in patients with syndrome X. Such downregulation would be consistent with raised myocardial catecholamine concentrations. We performed positron emission tomography with (11)C-CGP-12177 to measure beta-adrenoceptor density. Plasma catecholamines were sampled simultaneously and assayed using high-performance liquid chromatography. Twenty syndrome X patients (11 female, age 57 +/- 9 SD years, range 33 to 69) and 18 matched controls (9 women, age 50 +/- 13 years, range 25 to 65; p = NS vs patients) were studied. Myocardial beta-adrenoceptor density did not differ between syndrome X patients and controls: 8.0 (1.9) pmol/g for patients versus 8.3 (2.1) pmol/g for controls; p = 0.62. No differences were found between patients and controls for plasma norepinephrine (2.82 [1.07] and 2.76 [1.18] nM, respectively; p = 0.89) or for epinephrine (0.29 [0.14] and 0.30 [0.20] nM, respectively; p = 0.84). In patients with syndrome X, beta-adrenoceptor density is normal and, by inference, myocardial catecholamines would also be normal. This weakens the case for a generalized enhancement of sympathetic activation in this disorder, although increased sympathetic reactivity during actual episodes of chest pain remains a possibility.

Uptake of [N-methyl-11C]propionyl-L-carnitine (PLC) in human myocardium

We studied the uptake of propionyl-L-carnitine from plasma by the myocardium in 10 human subjects using positron emission tomography. Propionyl-L-carnitine was labeled in the N-methyl position with carbon-11 (T1/2 = 20.4 min) and administered i.v. in trace amounts. The uptake of the radiolabel by the myocardium was then scanned over a period of 1 1/2 h. The activity-time course of the tracer in blood and plasma and the exchange of the label in plasma between propionyl carnitine, acetyl carnitine and free carnitine was followed during the scans. Myocardial blood flow was also measured in the same subjects. The results show an exchange of the tracer between the myocardium and plasma, and they show an apparently irreversible component of uptake, a result consistent with the incorporation of the label into relatively large intracellular carnitine pools.

Dobutamine stress: effects on regional myocardial blood flow and wall motion

OBJECTIVES

This investigation studied the relation between regional myocardial blood flow and left ventricular function during dobutamine stress in patients with coronary artery disease.

BACKGROUND

Dobutamine stress is becoming more frequently used as an alternative to dynamic exercise in patients with ischemic heart disease.

METHODS

We studied 12 patients with coronary artery disease. Dobutamine was infused from 5 micrograms/kg body weight per min up to 40 micrograms/kg per min or until chest pain or other intolerable side effects. Regional myocardial blood flow was measured with positron emission tomography and oxygen-15-labeled water. Regional wall motion was assessed in three short-axis slices by magnetic resonance imaging. Each slice was subdivided into four regions: septal, anterior, lateral and inferior. A total of 140 regions were suitable for comparison.

RESULTS

During stress, new wall motion abnormalities developed in 27 regions. Myocardial blood flow (mean +/- SD) increased in 113 regions that did not develop wall motion abnormalities (0.98 +/- 0.26 [baseline] vs. 1.98 +/- 0.87 [dobutamine] ml/min per g, p < 0.001), whereas it did not change significantly in regions with stress-induced wall motion abnormalities (1.00 +/- 0.28 [baseline] vs. 1.30 +/- 0.62 [dobutamine] ml/min per g, p = NS). An absolute decrease in myocardial blood flow below the value at rest was observed in seven segments that developed wall motion abnormalities during stress.

CONCLUSIONS

The normal functional response to dobutamine stress is paralleled by an increase in coronary flow, whereas mechanical dysfunction is accompanied by a blunted increase, or even a paradoxic decrease, in regional coronary flow.

CRIB and SNAP: assessing the risk of death for preterm neonates

The performance of three scoring systems for assessing mortality risk for neonates--clinical risk index for babies (CRIB), score for neonatal acute physiology (SNAP), and SNAP's perinatal extension (SNAP-PE)--were tested in the same set of patients. In 222 neonates weighing less than 1500 g at birth, CRIB scores were significantly better for assessing mortality risk than SNAP (p = 0.017) or SNAP-PE (p < 0.001), areas under receiver operating characteristic curves being 0.89 (SE 0.02), 0.82 (0.03), and 0.79 (0.03), respectively. Male sex was independently associated with poor prognosis after taking the CRIB score into account with a risk ratio of 2.75. We conclude that CRIB is the most useful score for comparing the performance of neonatal intensive-care units. New treatment methods, however, may require modifications to the system.

Familial pericentric inversion inv(8)(p23q11)

We describe two families in whom a pericentric inversion, inv(8)(p23q11), is segregating. No examples of unbalanced karyotypes were encountered. The families originated from neighbouring parishes in western Finland. In one family a mild form of mental retardation segregated. However, this phenotype did not cosegregate with the inversion karyotype. There was no evidence of a higher than average abortion rate in the inversion carriers. Carrier matings produced 19 children with a balanced inversion and 14 children with a normal karyotype, concordant with a 1:1 segregation ratio. Of 13 karyotyped men at risk, 10 were inversion carriers. However, this difference was not statistically different from the expected 1:1 ratio. In females, the inversion carrier to normal ratio was 10:11.