The Significance of HL-A W27 in Ankylosing Spondylitis and Reiter's Syndrome with Three Family Studies

Summary: So as to test the diagnostic significance of tissue typing in an Australian population the HL-A antigens of forty-seven patients with Ankylosing Spondylitis and six patients with Reiter's Syndrome were compared with those found in three hundred and six controls. Since HL-A W27 was found in 92% of the patients with Ankylosing Spondylitis and all patients with Reiter's Syndrome it is concluded that these diagnoses should be questioned if this antigen cannot be demonstrated. In three family studies it was apparent that Ankylosing Spondylitis only occurred in those who had inherited HL-A W27 so that the absence of the antigen may help to identify those family members who will not develop the disease. Notwithstanding the association demonstrated the data argue against a close and simple linkage between the antigen and these diseases.     

The natural history of a genetic subtype of arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43

To determine the phenotype and natural history of a founder genetic subtype of autosomal dominant arrhythmogenic right ventricular cardiomyopathy (ARVC) caused by a p.S358L mutation in TMEM43. The age of onset of cardiac symptoms, clinical events and test abnormalities were studied in 412 subjects (258 affected and 154 unaffected), all of which occurred in affected males significantly earlier and more often than unaffected males. Affected males were hospitalized four times more often than affected females (p ≤ 0.0001) and died younger (p ≤ 0.001). The temporal sequence from symptoms onset to death was prolonged in affected females by 1–2 decades. The most prevalent electrocardiogram (ECG) manifestation was poor R wave progression (PRWP), with affected males twice as likely to develop PRWP as affected females (p ≤ 0.05). Left ventricular enlargement (LVE) occurred in 43% of affected subjects, with 11% fulfilling criteria for dilated cardiomyopathy. Ventricular ectopy on Holter monitor was common and occurred early: the most diagnostically useful clinical test. No symptom or test could rule out diagnosis. This ARVC subtype is a sex‐influenced lethal arrhythmogenic cardiomyopathy, with a unique ECG finding, LV dilatation, heart failure and early death, where molecular pre‐symptomatic diagnosis has the greatest clinical utility.     

Voltage-Gated Potassium Channels Ensure Action Potential Shape Fidelity in Distal Axons

The initiation and propagation of the action potential (AP) along an axon allows neurons to convey information rapidly and across distant sites. Although AP properties have typically been characterized at the soma and proximal axon, knowledge of the propagation of APs toward distal axonal domains of mammalian CNS neurons remains limited. We used genetically encoded voltage indicators (GEVIs) to image APs with submillisecond temporal resolution simultaneously at different locations along the long axons of dissociated hippocampal neurons from rat embryos of either sex. We found that APs became sharper and showed remarkable fidelity as they traveled toward distal axons, even during a high-frequency train. Blocking voltage-gated potassium channels (K_v) with 4-AP resulted in an increase in AP width in all compartments, which was stronger at distal locations and exacerbated during AP trains. We conclude that the higher levels of Kv channel activity in distal axons serve to sustain AP fidelity, conveying a reliable digital signal to presynaptic boutons.SIGNIFICANCE STATEMENT The AP represents the electrical signal carried along axons toward distant presynaptic boutons where it culminates in the release of neurotransmitters. The nonlinearities involved in this process are such that small changes in AP shape can result in large changes in neurotransmitter release. Since axons are remarkably long structures, any distortions that APs suffer along the way have the potential to translate into a significant modulation of synaptic transmission, particularly in distal domains. To avoid these issues, distal axons have ensured that signals are kept remarkably constant and insensitive to modulation during a train, despite the long distances traveled. Here, we uncover the mechanisms that allow distal axonal domains to provide a reliable and faithful digital signal to presynaptic terminals.     

Understanding Athletic Trainers' Beliefs Toward a Multifacted Sport-Related Concussion Approach: Application of the Theory of Planned Behavior

Context:

Practice guidelines recommend a multifaceted approach for managing concussions, but a relatively small percentage of athletic trainers (ATs) follow these recommendations. Understanding ATs'' beliefs toward the recommended concussion practice guidelines is the first step in identifying interventions that could increase compliance. The theory of planned behavior (TPB) allows us to measure ATs'' beliefs toward the recommended concussion practice guidelines.

Objective:

To examine the influence of ATs'' beliefs toward the current recommended concussion guidelines on concussion-management practice through an application of the TPB.

Design:

Cross-sectional study.

Setting:

A Web link with a survey was e-mailed to 1000 randomly selected members of the National Athletic Trainers'' Association (NATA).

Patients or Other Participants:

A total of 221 certified ATs working in secondary school/clinic, high school, and college/university settings.

Main Outcome Measure(s):

A 66-item survey reflecting the current recommended concussion guidelines of the NATA and International Conference on Concussion in Sport was created to measure beliefs using the TPB constructs attitude toward the behavior (BA), subjective norms (SN), perceived behavioral control (PBC), and behavioral intention (BI) of ATs. We used a linear multiple regression to determine if the TPB constructs BA, SN, and PBC predicted BI and if PBC and BI predicted behavior according to the TPB model.

Results:

We found that BA, SN, and PBC predicted BI (R = 0.683, R² = 0.466, F_3,202 = 58.78, P < .001). The BA (t₂₀₂ = 5.53, P < .001) and PBC (t₂₀₂ = 9.64, P < .001) contributed to the model, whereas SN (t₂₀₂ = −0.84, P = .402) did not. The PBC and BI predicted behavior (R = 0.661, R² = 0.437, F_2,203 = 78.902, P < .001).

Conclusions:

In this sample, the TPB constructs predicted BI and behavior of ATs'' compliance with recommended concussion-management guidelines. The BA and PBC were the most influential constructs, indicating that those with positive attitudes toward concussion-management recommendations are more likely to implement them, and ATs are less likely to implement them when they do not believe they have the power to do so. We theorize that interventions targeting ATs'' attitudes and control perceptions will lead to improved compliance.Key Words: concussion management, traumatic brain injuries, practice guidelines

Key Points

• Using the theory of planned behavior constructs to investigate the application of recommended concussion-management guidelines by athletic trainers, we found that attitudes toward the behavior and perceived behavioral control were most influential.
• Interventions that take into account athletic trainers'' attitudes and perceived control may help to increase compliance with concussion-management guidelines.

Given estimates of 1.6 to 3.8 million sport-related concussions occurring in the United States each year,¹ sports medicine professionals must be able to evaluate and manage concussions properly. With most athletic injuries, the sports medicine team can clearly define the presence and severity of an injury; however, factors such as an athlete''s age² and sex³ and the location and magnitude of an impact⁴ can make it difficult to clearly define the severity of a concussion.To help sports medicine professionals who care for concussed athletes, a number of organizations^5–8 have proposed the use of a multifaceted approach to evaluate and manage sport-related concussions. The guidelines established by these organizations for the evaluation and management of sport-related concussions endorse the use of (1) a clinical examination,^5,7,8 (2) a symptom checklist,⁶ (3) postural-control assessment,^6–8 (4) neuropsychological testing,^5–8 (5) baseline testing when available for high–concussion-risk athletes,^6,7 and (6) a return-to-play protocol with a daily increase in activity once an athlete has been deemed symptom free.^5–8 Also, the recommendations emphasize that it is imperative to focus on the athlete''s data gathered from the evaluation when making a return-to-play (RTP) decision throughout the concussion-management process rather than relying on a predetermined timeline.^6–8The multifaceted approach to evaluating and managing concussions has been recommended since 2002.⁵ Sports medicine professionals have shown a steady but slow increase in compliance with the recommendations over the past decade, yet barriers to incorporation of these standards remain.^9–11 To improve compliance, it is important to understand sports medicine professionals'' beliefs about the multifaceted approach to concussion management.¹² If we can understand why a minority of sports medicine professionals use recommended concussion-management guidelines, we can identify strategies to change common practices. The theory of planned behavior (TPB) offers an avenue to investigate these beliefs.The TPB focuses on theoretical constructs that are concerned with individual motivational factors (behavioral intention [BI]) as determinants of the likelihood of performing a specific behavior.^13–15 The TPB includes measures of attitude, subjective normative perceptions, and perceived behavioral control (PBC) that determine BI, with BI leading to a behavior. The TPB assumes that all other factors, including demographics and the environment, operate through the model constructs and do not independently contribute to explaining the likelihood of performing a behavior.The TPB has 4 guiding constructs: (1) attitude toward the behavior (BA), or an individual''s positive or negative evaluation of self-performance of a behavior and an individual''s belief about the consequences of that behavior; (2) subjective norms (SN), or an individual''s perception of what other persons think about the individual performing the behavior and the individual''s motivation to comply; (3) PBC, or a perception that the individual has control over performing a behavior; and (4) BI, or the individual''s intent to perform or not perform the behavior based on the weight of the first 3 constructs (Figure 1). The TPB depicts behavior (B) as a linear regression function: B = w₁BI + w₂PBC, where w₁ and w₂ are empirically determined weights.Open in a separate windowFigure 1. Theory of planned behavior results with Pearson r (beta weight) for each construct. ^a Significant at P < .001.The following is an example of how the TPB can help us understand the decision-making process of a sports medicine professional in determining whether to use a concussion-management technique. An athletic trainer (AT) believes it is important to implement neuropsychological testing after every concussion (BA). The AT may or may not be influenced by his or her perceptions about how the head coach feels regarding this concussion-management tool (SN). Finally, the AT must decide if he or she has enough authority in the athletic department to acquire the funds to purchase the neuropsychological tests (PBC). According to the TPB, the summation of these 3 constructs results in the AT''s intention to perform neuropsychological tests. An AT who intends to perform neuropsychological tests is more likely to do so. However, if the AT feels that he or she lacks full volitional control over the behavior (PBC), the BI may have less influence on behavior.To understand why a minority of sports medicine professionals are currently applying the concussion-management guidelines, we would like to understand their beliefs and perceptions regarding the guidelines. Therefore, the purpose of our study was to examine the influence of ATs'' attitudes and beliefs toward the current recommended concussion-management guidelines through an application of the TPB.     

Soy isoflavones improve cardiovascular disease risk markers in women during the early menopause

Background

Hormone replacement therapy may be beneficial for cardiovascular disease risk (CVR) in post-menopausal women. Soy isoflavones may act as selective estrogen receptor modulators. The aim of this study was to evaluate whether soy isoflavones had an effect on CVR markers.

Development and course of heart failure after a myocardial infarction in younger and older people

Background Acute myocardial infarction （AMI） is a common cause of heart failure （HF）, which can develop soon after AMI and may persist or resolve or develop late. HF after an MI is a major source of mortality. The cumulative incidence, prevalence and resolution of HF after MI in different age groups are poorly described. This study describes the natural history of HF after AMI according to age. Methods Patients with AMI during 1998 were identified from hospital records. HF was defined as treatment of symptoms and signs of HF with loop diuretics and was considered to have resolved if loop diuretic therapy could be stopped without recurrence of symptoms. Patients were cate- gorised into those aged 〈 65 years, 65-75 years, and 〉 75 years. Results Of 896 patients, 311,297 and 288 were aged 〈 65, 65-75 and 〉75 years and of whom 24%, 57% and 82% had died respectively by December 2005. Of these deaths, 24 （8%）, 68 （23%） and 107 （37%） oc- curred during the index admission, many associated with acute HF. A further 37 （12%）, 63 （21%） and 82 （29%） developed HF that persisted until discharge, of whom 15, 44 and 62 subsequently died. After discharge, 53 （24%）, 55 （40%） and 37 （47%） patients developed I-IF for the first time, of whom 26%, 62% and 76% subsequently died. Death was preceded by the development of HF in 35 （70%）, 93 （91%） and 107 （85%） in aged 〈 65 years, 65-75 years and 〉75 years, respectively. Conclusions The risk of developing HF and of dying after an MI in- creases progressively with age. Regardless of age, most deaths after a MI are preceded by the development of HF.