Qualitative measures that assess functional disability and quality of life in ALS.

BACKGROUND: Selection of appropriate trial endpoints and outcome measures is particularly important in rare disease and rapidly progressing disease such as amyotrophic lateral sclerosis (ALS) where the challenges to conducting clinical trials, are substantial: patient and disease heterogeneity, limited understanding of exact disease pathophysiology, and lack of robust and available biomarkers. To address these challenges in ALS, the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised version (ALSFRS-R) was developed and has become a key primary endpoint in ALS clinical trials to assess functional disability and disease progression, often replacing survival as a primary outcome. However, increased understanding of the ALS disease journey and improvements in assistive technology for ALS patients have exposed issues with the ALSFRS-R, including non-linearity, multidimensionality and floor and ceiling effects that could challenge its continued utility as a primary outcome measure in ALS clinical trials. Recently, other qualitative scale measures of functioning disability have been developed to help address these issues. With this in mind, we conducted a literature search aimed at identifying both established and promising new measures for potential use in clinical trials. METHODS: We searched PubMed, Google, Google Scholar, and the reference sections of key studies to identify papers that discussed qualitative measures of functional status for potential use in ALS studies. We also searched clinicaltrials.gov to identify functional status and health-related quality of life (HRQoL) measures that have been used in ALS interventional studies. RESULTS: In addition to the ALSFRS-R, we identified several newer qualitative scales including ALSFRS-EX, ALS-MITOS, CNS-BFS, DALS-15, MND-DS, and ROADS. Strengths and limitations of each measure were identified and discussed, along with their potential to act as a primary or secondary outcome to assess patient functional status in ALS clinical trials. CONCLUSION: This paper serves as a reference guide for researchers deciding which qualitative measures to use as endpoints in their ALS clinical trials to assess functional status. This paper also discusses the importance of including ALS HRQoL and ALS cognitive screens in future clinical trials to assess the value of a new ALS therapy more comprehensively.

Assessing Patients' Satisfaction With Hydrogen Peroxide Topical Solution, 40% for Treatment of Raised Seborrheic Keratoses.

OBJECTIVES: Assess participants’ satisfaction following treatment with a proprietary hydrogen peroxide topical solution 40%, w/w (HP40) for raised seborrheic keratoses (SKs). METHODS: In this Phase 4, open-label study, eligible participants aged 30–75 years had clinically typical raised SKs including 2 target SKs (Physician’s Lesion Assessment™ [PLA] grade of ≥2 [0 = clear; 1 = near clear; 2 = thin (≤1 mm); 3 = thick (>1 mm)]; 5–15 mm diameter) on the face and 1 target SK on the neck or décolletage. SKs received HP40 treatment on day 1. All SKs with PLA grade ≥1 were retreated on days 15 and 29. Endpoints included patients’ satisfaction with their skin’s appearance at day 113, relationships between patients’ satisfaction and lesion PLA grade (evaluated by chi-square test), and patients’ satisfaction with their treatment experience. RESULTS: Forty-one patients (mean [range] age, 62.4 [46–73] years) completed the study. 95% of patients were at least moderately satisfied with their skin’s appearance and 90.2% of target lesions were clear. A statistically significant association was observed between the number of target lesions achieving clearance and patients’ satisfaction with skin appearance level (χ2=22.03; P=0.001). 93% of patients were at least moderately satisfied with their HP40 treatment experience. Eight patients experienced treatment-emergent adverse events (TEAEs), most of which were mild or moderate; 4 experienced TEAEs considered treatment-related. CONCLUSIONS: Most patients with SKs on the face, neck, and décolletage were satisfied or very satisfied with both their skin’s appearance and their treatment experience following HP40 treatment. These results support the use of HP40 for raised SKs. J Drugs Dermatol. 2020;19(12): doi:10.36849/JDD.2020.4974.

Costs of Severe Maternal Morbidity During Pregnancy in US Commercially Insured and Medicaid Populations: An Observational Study.

OBJECTIVE: To estimate the maternity-related cost of health care services in women with and without severe maternal morbidity (SMM). METHODS: Women with a live inpatient birth in the calendar year 2013 were identified in the MarketScan® Commercial and Medicaid health insurance claims databases. Costs were defined as the amounts paid by insurers plus out-of-pocket and third-party payments. Costs were calculated as total maternity-related costs and categorized as prenatal, delivery, and postpartum costs. SMM was identified using the CDC algorithm of 25 ICD-9 diagnostic and procedural codes. Variables associated with higher delivery costs were determined by multivariable linear regression analysis. RESULTS: A total of 750 women met the criteria for SMM in the Commercial population. The total, per-patient mean costs of care for women without and with SMM were $14,840 and $20,380, respectively. Delivery hospitalization costs were 76-77% of total mean costs for women without and with SMM. A total of 99 women met the criteria for SMM in the Medicaid population. The total, per-patient mean costs of care for women without and with SMM were $6894 and $10,134, respectively. Delivery costs were 71-72% of total costs. Variables independently predictive of increased delivery costs in both Commercial and Medicaid populations were delivery by cesarean section, multifetal gestation, gestational hypertension/preeclampsia, and obstetric infection. CONCLUSIONS: The occurrence of SMM was associated with an increase in maternity-related costs of 37% in the Commercial and 47% in the Medicaid population. Some of the factors associated with increased delivery hospitalization costs may be prevented.

Doing research in non-specialist mental health services for children and young people: lessons learnt from a process evaluation of the ICALM (Interpersonal Counselling for Adolescent Low Mood) feasibility randomised controlled trial.

BACKGROUND: The rising prevalence of adolescent mild depression in the UK and the paucity of evidence-based interventions in non-specialist sectors where most cases present, creates an urgent need for early psychological interventions. Randomised controlled trials (RCTs) are considered the gold standard for obtaining unbiased estimates of intervention effectiveness. However, the complexity of mental health settings poses great challenges for effectiveness evaluations. This paper reports learning from an embedded process evaluation of the ICALM RCT which tested the feasibility of delivering Interpersonal Counselling for Adolescents (IPC-A) plus Treatment as Usual (TAU) versus TAU only for adolescent (age 12-18) mild depression by non-qualified mental health professionals in non-specialist sectors. METHODS: A qualitative mixed methods process evaluation, drawing on Bronfenbrenner's socioecological model to investigate key influences on trial delivery across macro-(e.g. policy), meso-(e.g. service characteristics) and micro-(e.g. on-site trial processes) contextual levels. Data collection methods included 9 site questionnaires, 4 observations of team meetings, policy documents, and 18 interviews with stakeholders including therapists, heads of service and managers. Thematic analysis focused on understanding how contextual features shaped trial implementation. RESULTS: The ICALM trial concluded in 2022 having only randomised 14 out of the target 60 young people. At a macro-level, trial delivery was impacted by the COVID-19 pandemic, with services reporting a sharp increase in cases of (social) anxiety over low mood, and backlogs at central referral points which prolonged waiting times for mild cases (e.g. low mood). An interaction between high demand and lack of capacity at a meso-service level led to low prioritisation of trial activities at a micro-level. Unfamiliarity with research processes (e.g. randomisation) and variation in TAU support also accentuated the complexities of conducting an RCT in this setting. CONCLUSIONS: Conducting a RCT of IPC-A in non-specialist services is not feasible in the current context. Failure to conduct effectiveness trials in this setting has clinical implications, potentially resulting in escalation of mild mental health problems. Research done in this setting should adopt pragmatic and innovative recruitment and engagement approaches (e.g. creating new referral pathways) and consider alternative trial designs, e.g. cluster, stepped-wedge or non-controlled studies using complex systems approaches to embrace contextual complexity. TRIAL REGISTRATION: ISRCTN registry, ISRCTN82180413. Registered on 31 December 2019.

Distribution and associations of [-2]proenzyme-prostate specific antigen in community dwelling black and white men.

PURPOSE: We provide cross-sectional normative data on [-2]proenzyme-prostate specific antigen from the Olmsted County Study of Urinary Symptoms and Health Status among Men, and the Flint Men's Health Study. We also describe associations with clinical urological measures and the risk of prostate cancer diagnosis. MATERIALS AND METHODS: Measurements of [-2]proenzyme-prostate specific antigen were obtained from 420 white men from Olmsted County, Minnesota, and 328 black men from Genesee County, Michigan. Cross-sectional associations between [-2]proenzyme-prostate specific antigen and prostate enlargement/elevated prostate specific antigen were assessed. Cox proportional hazard models were used to assess associations between [-2]proenzyme-prostate specific antigen and the incident diagnosis of prostate cancer. RESULTS: Baseline [-2]proenzyme-prostate specific antigen was slightly higher in black men at a median of 6.3 pg/ml (25th, 75th percentiles 4.1, 8.9) than in white men at a median of 5.6 pg/ml (25th, 75th percentiles 3.9, 7.7, respectively, p = 0.01). Baseline [-2]proenzyme-prostate specific antigen was highly predictive of biopsy confirmed prostate cancer in the Olmsted County Study cohort. Relative to men in the [-2]proenzyme-prostate specific antigen lower quartile those in the upper quartile were at almost eightfold increased risk for prostate cancer (HR 7.8, 95% CI 2.2-27.8) after adjusting for age and baseline prostate specific antigen. CONCLUSIONS: In these cohorts of community dwelling black and white men [-2]proenzyme-prostate specific antigen was much lower than in previous studies. These data suggest that [-2]proenzyme-prostate specific antigen may help identify prostate cancer in men with serum prostate specific antigen in an indeterminate range, although the reference ranges for white and black men may differ slightly.

Benign prostate specific antigen distribution and associations with urological outcomes in community dwelling black and white men.

PURPOSE: We describe cross-sectional associations of benign prostate specific antigen with clinical urological measures and examined the risk of future urological outcomes in 2 population based cohorts of black and white men, respectively. MATERIALS AND METHODS: Two population based cohort studies were established to characterize the natural history of and risk factors for prostate disease progression in white and black male residents of Olmsted County, Minnesota, and Genesee County, Michigan, respectively. RESULTS: The benign prostate specific antigen distribution was similar in black men at a median of 32.9 pg/ml (25th, 75th percentiles 17.3, 68.0) and white men at a median of 32.2 pg/ml (25th, 75th percentiles 16.6, 68.9, respectively). However, it was much lower than in previous reports. For Olmsted County men in the upper quartile of benign prostate specific antigen there was a fifteenfold increased risk of prostate cancer (HR 14.6, 95% CI 3.1-68.6) and a twofold higher risk of treatment for benign prostatic hyperplasia (HR 2.2, 95% CI 1.2-4.2) after adjusting for age. After additional adjustment for baseline prostate specific antigen the association between benign prostate specific antigen and prostate cancer risk was attenuated but remained almost ninefold higher for men in the upper quartile of benign prostate specific antigen (HR 8.7, 95% CI 1.8-42.4). The twofold higher risk of treatment for benign prostatic hyperplasia also remained after adjusting for baseline prostate specific antigen for men in the upper benign prostate specific antigen quartile (HR 1.9, 95% CI 0.9-4.0). CONCLUSIONS: Results suggest that increased benign prostate specific antigen may help identify men with prostate cancer and those at risk for benign prostatic hyperplasia treatment.

Risk of bias in non-randomized observational studies assessing the relationship between proton-pump inhibitors and adverse kidney outcomes: a systematic review.

BACKGROUND: Proton-pump inhibitors (PPIs) are widely prescribed as acid-suppression therapy. Some observational studies suggest that long-term use of PPIs is potentially associated with certain adverse kidney outcomes. We conducted a systematic literature review to assess potential bias in non-randomized studies reporting on putative associations between PPIs and adverse kidney outcomes (acute kidney injury, acute interstitial nephritis, chronic interstitial nephritis, acute tubular necrosis, chronic kidney disease, and end-stage renal disease). METHODS: We searched the medical literature within 10 years of 17 December 2020. Pre-specified criteria guided identification of relevant English language articles for assessment. Risk of bias on an outcome-specific basis was evaluated using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool by two independent reviewers. RESULTS: Of 620 initially identified records, 26 studies met a priori eligibility criteria and underwent risk of bias assessment. Nineteen studies were judged as having a moderate risk of bias for reported adverse kidney outcomes, while six studies were judged as having a serious risk of bias (mainly due to inadequate control of confounders and selection bias). We were unable to determine the overall risk of bias in two studies (one of which was assessed as having a moderate risk of bias for a different adverse kidney outcome) due to insufficient information presented. Effect estimates for PPIs in relation to adverse kidney outcomes varied widely (0.24-7.34) but associations mostly showed increased risk. CONCLUSION: Using ROBINS-I, we found that non-randomized observational studies suggesting kidney harm by PPIs have moderate to serious risk of bias, making it challenging to establish causality. Additional high-quality, real-world evidence among generalizable populations are needed to better understand the relation between PPI treatment and acute and chronic kidney outcomes, accounting for the effects of varying durations of PPI treatment, self-treatment with over-the-counter PPIs, and potential critical confounders.

Divergent sodium channel defects in familial hemiplegic migraine.

Familial hemiplegic migraine type 3 (FHM3) is a severe autosomal dominant migraine disorder caused by mutations in the voltage-gated sodium channel Na(V)1.1 encoded by SCN1A. We determined the functional consequences of three mutations linked to FHM3 (L263V, Q1489K, and L1649Q) in an effort to identify molecular defects that underlie this inherited migraine disorder. Only L263V and Q1489K generated quantifiable sodium currents when coexpressed in tsA201 cells with the human beta(1) and beta(2) accessory subunits. The third mutant, L1649Q, failed to generate measurable whole-cell current because of markedly reduced cell surface expression. Compared to WT-Na(V)1.1, Q1489K exhibited increased persistent current but also enhanced entry into slow inactivation as well as delayed recovery from fast and slow inactivation, thus resulting in a predominantly loss-of-function phenotype further demonstrated by a greater loss of channel availability during repetitive stimulation. In contrast, L263V exhibited gain-of-function features, including delayed entry into, as well as accelerated recovery from, fast inactivation; depolarizing shifts in the steady-state voltage dependence of fast and slow inactivation; increased persistent current; and delayed entry into slow inactivation. Notably, the two mutations (Q1489K and L1649Q) that exhibited partial or complete loss of function are linked to typical FHM, whereas the gain-of-function mutation L263V occurred in a family having both FHM and a high incidence of generalized epilepsy. We infer from these data that a complex spectrum of Na(V)1.1 defects can cause FHM3. Our results also emphasize the complex relationship between migraine and epilepsy and provide further evidence that both disorders may share common molecular mechanisms.

Efficacy of Vibegron and Mirabegron for Overactive Bladder: A Systematic Literature Review and Indirect Treatment Comparison.

BACKGROUND: In the absence of head-to-head trials, we performed an indirect treatment comparison of the ß3-adrenergic agonists vibegron and mirabegron in the treatment of overactive bladder (OAB). METHODS: PubMed, Embase, and Cochrane Library were searched for articles related to phase 3, double-blind, controlled trials of vibegron 75 mg and mirabegron 25/50 mg in patients with OAB. Efficacy outcomes included change from baseline at weeks 4, 12, and 52 in mean daily number of total urinary incontinence episodes and micturitions and mean volume voided/micturition. Effect size was computed as placebo-subtracted change from baseline (weeks 4, 12) or active control (tolterodine)-subtracted change from baseline (week 52) for each treatment group. Adverse events (AEs) are presented descriptively. RESULTS: After removal of duplicates, 49 records were identified, and after screening 9 met inclusion criteria for analysis. Vibegron showed significantly greater reduction in mean daily number of total incontinence episodes than mirabegron 25 mg at week 4, mirabegron 50 mg (weeks 4, 52), and tolterodine (weeks 4, 12) (P < 0.05, each) and significantly greater improvement in volume voided versus mirabegron 25 mg (week 12), mirabegron 50 mg (weeks 12, 52), and tolterodine (week 4) (P < 0.05, each). Confidence intervals of point estimates overlapped zero for all other comparisons of vibegron and mirabegron (25 or 50 mg) or tolterodine, indicating no significant differences between treatments for these time/endpoints. Urinary tract infection, hypertension, and dry mouth were the most commonly occurring AEs for vibegron, mirabegron, and tolterodine, respectively, in the short-term trials; hypertension was the most commonly occurring AE with all three treatments in the long-term trials. CONCLUSIONS: Vibegron was associated with significant improvement in total incontinence episodes versus mirabegron at 4 and 52 weeks and volume voided at 12 and 52 weeks. Improvement in micturitions was similar between vibegron and mirabegron or tolterodine. Incidence of AEs was generally comparable between vibegron and mirabegron.

A Descriptive Review of Global Real World Evidence Efforts to Advance Drug Discovery and Clinical Development in Amyotrophic Lateral Sclerosis.

Understanding patient clinical progression is a key gateway to planning effective clinical trials and ultimately enabling bringing treatments to patients in need. In a rare disease like amyotrophic lateral sclerosis (ALS), studies of disease natural history critically depend on collaboration between clinical centers, regions, and countries to enable creation of platforms to allow patients, caregivers, clinicians, and researchers to come together and more fully understand the condition. Rare disease registries and collaborative platforms such as those developed in ALS collect real-world data (RWD) in standardized formats, including clinical and biological specimen data used to evaluate risk factors and natural history of disease, treatment patterns and clinical (ClinROs) and patient- reported outcomes (PROs) and validate novel endpoints. Importantly, these data support the development of new therapeutics by supporting the evaluation of feasibility and design of clinical trials and offer valuable information on real-world disease trajectory and outcomes outside of the clinical trial setting for comparative purposes. RWD may help to accelerate therapy development by identifying and validating outcome measures and disease subpopulations. RWD can also make potential contributions to the evaluation of the safety and effectiveness of new indications for approved products and to satisfy post-approval regulatory and market access requirements. There is a lack of amalgamated information on available registries, databases, and other sources of real-world data on ALS; thus, a global review of all available resources was warranted. This targeted review identifies and describes ALS registries, biobanks and collaborative research networks that are collecting and synthesizing RWD for the purposes of increasing patient awareness and advancing scientific knowledge with the hope of expediting future development of new therapies.

Divergent biophysical defects caused by mutant sodium channels in dilated cardiomyopathy with arrhythmia.

Mutations in SCN5A encoding the principal Na+ channel alpha-subunit expressed in human heart (Na(V)1.5) have recently been linked to an inherited form of dilated cardiomyopathy with atrial and ventricular arrhythmia. We compared the biophysical properties of 2 novel Na(V)1.5 mutations associated with this syndrome (D2/S4--R814W; D4/S3--D1595H) with the wild-type (WT) channel using heterologous expression in cultured tsA201 cells and whole-cell patch-clamp recording. Expression levels were similar among WT and mutant channels, and neither mutation affected persistent sodium current. R814W channels exhibited prominent and novel defects in the kinetics and voltage dependence of activation characterized by slower rise times and a hyperpolarized conductance-voltage relationship resulting in an increased "window current." This mutant also displayed enhanced slow inactivation and greater use-dependent reduction in peak current at fast pulsing frequencies. By contrast, D1595H channels exhibited impaired fast inactivation characterized by slower entry into the inactivated state and a hyperpolarized steady-state inactivation curve. Our findings illustrate the divergent biophysical defects caused by 2 different SCN5A mutations associated with familial dilated cardiomyopathy. Retrospective review of the published clinical data suggested that cardiomyopathy was not common in the family with D1595H, but rather sinus bradycardia was the predominant clinical finding. However, for R814W, we speculate that an increased window current coupled with enhanced slow inactivation and rate-dependent loss of channel availability provided a unique substrate predisposing myocytes to disordered Na+ and Ca2+ homeostasis leading to myocardial dysfunction.

Natural history of benign prostatic enlargement: long-term longitudinal population-based study of prostate volume doubling times.

OBJECTIVES: To measure prostate volume doubling times (PVDTs) for a large sample of community men followed serially by transrectal ultrasonography (TRUS), and to determine whether specific characteristics are associated with a rapid PVDT. SUBJECTS AND METHODS: A subsample of 446 subjects from a larger cohort of American white men aged 40-79 years were evaluated biennially for a median (range) follow-up of 10 (3-14) years. Mixed-effects regression models were used to estimate prostate growth rates and PVDT for subjects with three or more or with five or more serial biennial TRUS PV measurements. RESULTS: The median (25-75th percentile) PVDT was 32.6 (24.6-44.0) years. The average annual increase in PV was 2.2%. The PVDT distribution was constant in men of all age groups studied (r < 0.001, P = 0.99). The factor most strongly associated with PVDT was baseline transition zone volume (r = -0.55, P < 0.001). Baseline total prostate-specific antigen (PSA) level, free PSA and total PV were also significantly inversely associated with PVDT (r = -0.30, -0.44 and -0.32, respectively, all P < 0.001). Age, baseline anthropomorphic measurements, hormone levels and specific lifestyle characteristics were not significantly correlated with PVDT. CONCLUSION: These data indicate that PVDT might be a useful future measure of benign prostatic growth. They provide a basis to forecast PV at 10, 20, or 30 years later, after one baseline TRUS measurement of prostate volume, and can be presented in a simple nomogram.

Software Assurance Using Structured Assurance Case Models.

Software assurance is an important part of the software development process to reduce risks and ensure that the software is dependable and trustworthy. Software defects and weaknesses can often lead to software errors and failures and to exploitation by malicious users. Testing, certification and accreditation have been traditionally used in the software assurance process to attempt to improve software trustworthiness. In this paper, we examine a methodology known as a structured assurance model, which has been widely used for assuring system safety, for its potential application to software assurance. We describe the structured assurance model and examine its application and use for software assurance. We identify strengths and weaknesses of this approach and suggest areas for further investigation and testing.

Clinical Course of Patients With Worsening Heart Failure With Reduced Ejection Fraction.

BACKGROUND: Epidemiology of patients with worsening heart failure and reduced ejection fraction (HFrEF) in the real-world setting is not well described. OBJECTIVES: The purpose of this study was to describe incidence, clinical characteristics, treatment, and outcomes of patients with HFrEF who develop worsening heart failure (HF) in the real-world setting. METHODS: Data on patients with incident HFrEF from the National Cardiovascular Data Registry PINNACLE were linked to pharmacy, private practitioner, and hospital claims databases. Incidence, clinical characteristics, treatment (angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist) and outcomes of patients with worsening HF, defined as ≥90 days of stable HF with subsequent worsening requiring intravenous diuretic agents, were assessed. RESULTS: Of 11,064 HFrEF patients, 1,851 (17%) developed worsening HF on average 1.5 years following initial HF diagnosis. Patients who developed worsening HF were more likely to be African American, be octogenarians, and have higher comorbidity burden (p < 0.001). At the onset of worsening HF, 42.4% of patients were on monotherapy, 43.4% were on dual therapy, and 14.1% were on triple therapy. A total of 48%, 61%, and 98% of patients were on >50% target dose for angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, beta-blocker, and mineralocorticoid receptor antagonist, respectively. The 2-year mortality rate was 22.5%, and 56% of patients were rehospitalized within 30 days of the worsening HF event. CONCLUSIONS: In the real-world setting, 1 in 6 patients with HFrEF develop worsening HF within 18 months of HF diagnosis. These patients have a high risk for 2-year mortality and recurrent HF hospitalizations. The use of standard-of-care therapies both before and after the onset of worsening HF is low. With high unmet medical need, patients with worsening HF require novel treatment strategies as well as greater optimization of existing guideline-directed therapy.

Molecular basis of an inherited epilepsy.

Epilepsy is a common neurological condition that reflects neuronal hyperexcitability arising from largely unknown cellular and molecular mechanisms. In generalized epilepsy with febrile seizures plus, an autosomal dominant epilepsy syndrome, mutations in three genes coding for voltage-gated sodium channel alpha or beta1 subunits (SCN1A, SCN2A, SCN1B) and one GABA receptor subunit gene (GABRG2) have been identified. Here, we characterize the functional effects of three mutations in the human neuronal sodium channel alpha subunit SCN1A by heterologous expression with its known accessory subunits, beta1 and beta2, in cultured mammalian cells. SCN1A mutations alter channel inactivation, resulting in persistent inward sodium current. This gain-of-function abnormality will likely enhance excitability of neuronal membranes by causing prolonged membrane depolarization, a plausible underlying biophysical mechanism responsible for this inherited human epilepsy.

Some legal thoughts on the unhappy patient.

Not all patients are happy with their results. When things become adversarial, facial plastic surgeons need a sound strategy in order to deal with the potential cascading legal events that may ensue. The attorney author of this article offers step-by-step advice for handling complaints brought by patients unhappy with surgical outcome. Also presented are discussions of avoidance of lawsuits and physician preparation for inquiry from state medical boards.

Congenital sick sinus syndrome caused by recessive mutations in the cardiac sodium channel gene (SCN5A).

Sick sinus syndrome (SSS) describes an arrhythmia phenotype attributed to sinus node dysfunction and diagnosed by electrocardiographic demonstration of sinus bradycardia or sinus arrest. Although frequently associated with underlying heart disease and seen most often in the elderly, SSS may occur in the fetus, infant, and child without apparent cause. In this setting, SSS is presumed to be congenital. Based on prior associations with disorders of cardiac rhythm and conduction, we screened the alpha subunit of the cardiac sodium channel (SCN5A) as a candidate gene in ten pediatric patients from seven families who were diagnosed with congenital SSS during the first decade of life. Probands from three kindreds exhibited compound heterozygosity for six distinct SCN5A alleles, including two mutations previously associated with dominant disorders of cardiac excitability. Biophysical characterization of the mutants using heterologously expressed recombinant human heart sodium channels demonstrate loss of function or significant impairments in channel gating (inactivation) that predict reduced myocardial excitability. Our findings reveal a molecular basis for some forms of congenital SSS and define a recessive disorder of a human heart voltage-gated sodium channel.

Single-channel properties of human NaV1.1 and mechanism of channel dysfunction in SCN1A-associated epilepsy.

Mutations in genes encoding neuronal voltage-gated sodium channel subunits have been linked to inherited forms of epilepsy. The majority of mutations (>100) associated with generalized epilepsy with febrile seizures plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI) occur in SCN1A encoding the NaV1.1 neuronal sodium channel alpha-subunit. Previous studies demonstrated functional heterogeneity among mutant SCN1A channels, revealing a complex relationship between clinical and biophysical phenotypes. To further understand the mechanisms responsible for mutant SCN1A behavior, we performed a comprehensive analysis of the single-channel properties of heterologously expressed recombinant WT-SCN1A channels. Based on these data, we then determined the mechanisms for dysfunction of two GEFS+-associated mutations (R1648H, R1657C) both affecting the S4 segment of domain 4. WT-SCN1A has a slope conductance (17 pS) similar to channels found in native mammalian neurons. The mean open time is approximately 0.3 ms in the -30 to -10 mV range. The R1648H mutant, previously shown to display persistent sodium current in whole-cell recordings, exhibited similar slope conductance but had an increased probability of late reopening and a subfraction of channels with prolonged open times. We did not observe bursting behavior and found no evidence for a gating mode shift to explain the increased persistent current caused by R1648H. Cells expressing R1657C exhibited conductance, open probability, mean open time, and latency to first opening similar to WT channels but reduced whole-cell current density, suggesting decreased number of functional channels at the plasma membrane. In summary, our findings define single-channel properties for WT-SCN1A, detail the functional phenotypes for two human epilepsy-associated sodium channel mutants, and clarify the mechanism for increased persistent sodium current induced by the R1648H allele.

Plasma cytokines, metabolic syndrome, and atherosclerosis in humans.

BACKGROUND: Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) integrate inflammatory and adipose signaling but also have direct vascular effects. We hypothesized that plasma levels of IL-6 and soluble tumor necrosis factor alpha receptor 2 (sol-TNFR2) would be related to coronary atherosclerosis beyond established risk factors and the metabolic syndrome. METHODS: We examined the association of IL-6 and sol-TNFR2 with metabolic syndrome, C-reactive protein (CRP), and coronary artery calcification (CAC) in 875 asymptomatic participants in the Study of Inherited Risk of Coronary Atherosclerosis. RESULTS: IL-6 levels were 56% higher (p < .001) and sol-TNFR2 levels 16% higher (p < .001) in subjects with metabolic syndrome compared with those without. Both cytokines were associated with CAC beyond age, gender, Framingham risk scores, family history, metabolic syndrome, and CRP (odds ratio and 95% confidence interval of higher CAC for 1 SD increase in log-transformed cytokine levels: 1.23 [1.06-1.43], p = .006 for IL-6 and 1.15 [1.01-1.31], p = .04 for sol-TNFR2). In fact, cytokine levels were independently associated with CAC scores in the subgroup with metabolic syndrome and were additive to the homeostasis model assessment of insulin resistance in predicting CAC. CONCLUSIONS: Plasma IL-6 and sol-TNFR2 levels were independently associated with CAC, suggesting a role in integrating innate immune and adipose signaling in promoting atherosclerosis and cardiovascular risk. Measurement of their levels may facilitate cardiovascular risk prediction and targeting of therapeutic strategies.