Neutrophil proteases degrade autoepitopes of NET-associated proteins

Neutrophils can form neutrophil extracellular traps (NETs) to capture microbes and facilitate their clearance. NETs consist of decondensed chromatin decorated with anti-microbial proteins. Here, we describe the effect of neutrophil proteases on the protein content of NETs. We show that the neutrophil serine proteases degrade several neutrophil proteins associated with NETs. Interestingly, the anti-bacterial proteins associated with NETs, such as myeloperoxidase, calgranulin B and neutrophil elastase (NE), seem to be less susceptible to proteolytic degradation than other NET proteins, such as actin and MNDA. NETs have been proposed to play a role in autoimmune reactions. Our data demonstrate that a large number of the autoepitopes of NET proteins that are recognized by autoantibodies produced by systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) patients are also removed by the proteases. In conclusion, neutrophil serine proteases have a major impact on the NET proteome and the proteolytic changes of NET-associated proteins may counteract autoimmune reactions to NET components.     

Reappraisal of Left Ventricular to Right Atrial (LV-RA) Shunt in Pediatric Patients With Isolated Perimembranous Ventricular Septal Defect

Background The purpose of this study was to investigate the follow-up results of perimembranous ventricular septal defect (VSD) with left ventricular to right atrial (LV-RA) shunt since infancy and to analyze the morphologic variations of this shunt. Methods and Results The study group comprised 232 consecutive pediatric patients with isolated perimembranous VSD and aneurysm, of whom 134 (58%) had LV-RA shunts. Follow-up echocardiography was performed to assess for the size of both the VSD and LV-RA shunt. There were no significant differences between groups in terms of sex, age at the initial echocardiography, follow-up period, number of patients with tricuspid regurgitation, and initial VSD size. There was a significant difference between groups in spontaneous closure (p=0.039). The event-free probability (no surgical repair of the defect) was not significantly different between the groups (p=0.129). Conclusions Perimembranous VSD with LV-RA shunt in infancy is common and associated with less chance of spontaneous closure. Color Doppler echocardiography can greatly improves the diagnostic efficacy and assist in understanding the mechanisms leading to this particular anomaly. (Circ J 2008; 72: 1487 - 1491).     

Size and speed of the working stroke of cardiac myosin in situ

The power in the myocardium sarcomere is generated by two bipolar arrays of the motor protein cardiac myosin II extending from the thick filament and pulling the thin, actin-containing filaments from the opposite sides of the sarcomere. Despite the interest in the definition of myosin-based cardiomyopathies, no study has yet been able to determine the mechanokinetic properties of this motor protein in situ. Sarcomere-level mechanics recorded by a striation follower is used in electrically stimulated intact ventricular trabeculae from the rat heart to determine the isotonic velocity transient following a stepwise reduction in force from the isometric peak force T_P to a value T (0.8–0.2 T_P). The size and the speed of the early rapid shortening (the isotonic working stroke) increase by reducing T from ∼3 nm per half-sarcomere (hs) and 1,000 s⁻¹ at high load to ∼8 nm⋅hs⁻¹ and 6,000 s⁻¹ at low load. Increases in sarcomere length (1.9–2.2 μm) and external [Ca²⁺]_o (1–2.5 mM), which produce an increase of T_P, do not affect the dependence on T, normalized for T_P, of the size and speed of the working stroke. Thus, length- and Ca²⁺-dependent increase of T_P and power in the heart can solely be explained by modulation of the number of myosin motors, an emergent property of their array arrangement. The motor working stroke is similar to that of skeletal muscle myosin, whereas its speed is about three times slower. A new powerful tool for investigations and therapies of myosin-based cardiomyopathies is now within our reach.The performance of heart depends on the power developed by the myocardium, which in turn is strongly dependent on the end-diastolic volume modulating the systolic pressure development (Frank–Starling law of the heart). At the level of the sarcomere, the structural unit of striated muscle, the Frank–Starling law originates from the increase in the force of contraction with an increase in sarcomere length (length-dependent activation). Mutations of sarcomere proteins affect power output and are considered responsible for various forms of cardiomyopathy (1, 2). Over 250 mutations in cardiac myosin II have been reported as the cause of cardiomyopathies (1, 3, 4). Defining the mechanokinetic properties of the cardiac myosin in situ is therefore fundamental to understand the pathomechanisms of these cardiomyopathies and to provide previously unidentified therapeutic opportunities.In the sarcomere, the myosin motors are organized in two bipolar arrays extending from the thick filament and pulling the thin actin-containing filaments from the opposite sides of the sarcomere toward its center. In each array, the myosin motors are connected in parallel via their attachments to the thick filament and the resulting collective motor provides steady force and shortening by cyclic asynchronous ATP-driven actin–myosin interactions. Thus, the performance of the heart relies on the integration of the mechanokinetic properties of the myosin motor and the properties emerging from its array arrangement in the half-sarcomere (hs). Using sarcomere-level mechanics in intact cells from the skeletal muscle, it has been shown that the isotonic velocity transient following stepwise changes in force imposed on the otherwise isometric contraction contains information on both the working stroke of the myosin motor and the steady-state force–velocity (T–V) relation resulting from the cyclic actin–myosin interactions and accounting for the power output (5–9).Here, this approach is applied for the first time (to our knowledge) to a multicellular cardiac preparation like the intact trabecula dissected from the right ventricle of the rat heart. A striation follower (10) proved to be a reliable tool for measurement of sarcomere length changes with nanometer–microsecond resolution owing to optical averaging of the image of the sarcomeres that reduces the background noise originating from intracellular and intercellular components of the trabecula. Following the original idea by ter Keurs et al. (11), the sarcomere shortening recorded during the force development in a fixed-end twitch is used as a feedforward signal to maintain sarcomere length constant during the next twitch. By switching from length control to force control, a stepwise drop in force was imposed at the peak of force (T_P) to record the isotonic velocity transient. In this way, the amplitude and speed of the rapid phase of the transient (phase 2), which is the mechanical manifestation of the myosin working stroke, could be determined. Increases in sarcomere length (SL) from 1.9 to 2.2 μm and in the external Ca²⁺ concentration ([Ca²⁺]_o) from 1 to 2.5 mM, which produce an increase in T_P, do not affect the myosin working stroke. This indicates that length-dependent potentiation of cardiac contractility is fully accounted for by an increase in the number of attached myosin motors. These experiments demonstrate that our sarcomere-level mechanical methods have the full potential for the in situ investigation of cardiomyopathy-causing mutations in cardiac myosin.     

Visual Functioning Questionnaire: reevaluation of psychometric properties for a group of working-age adults.

PURPOSE: The Visual Functioning Questionnaire (VFQ-25) is one of the most widely used measures of vision-related quality of life. However, the questionnaire does not meet some psychometric quality criteria. The objectives of this study were first to obtain the factor structure of the VFQ-25, and second, to obtain interval scales by Rasch analysis. METHODS: The questionnaire was administered to 129 visually impaired adults (mean age 42.1 years; range 21 to 67 years). First, the items of the VFQ-25 were subjected to an exploratory factor analysis with Promax rotation. Next, we performed a separate Rasch analysis on each factor. We examined step thresholds and goodness of fit statistics of the items. Finally, we examined differential item functioning. RESULTS: Factor analysis indicated four factors: Near Activities, Distance Activities and Mobility, Mental Health and Dependency, and Pain and Discomfort. They accounted for 46.37% of the total variance. Most items showed some degree of disordering. After collapsing response categories, all items showed ordered thresholds. The Near Activities domain showed excellent fit, whereas the Distance Activities and Mobility domain, the Mental Health and Dependency domain, and the Pain and Discomfort domain had an unsatisfactory fit. There were two items showing uniform differential item functioning. CONCLUSIONS: The four-factor structure of the VFQ-25 largely confirms the structure of the questionnaire. However, the results of this study suggest that modifications of the original VFQ-25 structure are necessary.     

Sialographic and ultrasonographic analyses of major salivary glands

Seventy patients with major salivary gland diseases (60 parotis, 10 submandibular) were examined both with sialography and ultrasonography. The clinical and histopathological results were compared with radiological interpretations. Sialography was found to be 60% accurate for the diagnosis of salivary gland tumors and cysts and 63% for the diagnosis of inflammatory diseases. Ultrasonography diagnosed 95% of the tumors and 63% of inflammatory diseases accurately.     

A modified technique for perineal colorectal, coloanal or ileoanal anastomosis with the EEA stapler

A new technique of using the EEA stapler for perineal colorectal, coloanal and ileoanal anastomoses has been described. This technique is of greatest use in very low anterior resection and in rectal procedentia.     

Rho proteins, mental retardation and the cellular basis of cognition

For several decades, it has been known that mental retardation (MR) is associated with abnormalities in dendrites and dendritic spines. The recent cloning of seven genes that cause nonspecific MR when mutated provides important insights in the cellular mechanisms that result in the dendritic abnormalities associated with MR. Three of the encoded proteins, oligophrenin 1, PAK3 and alpha PIX, interact directly with Rho GTPases. Rho GTPases are key signaling proteins that integrate extracellular and intracellular signals to orchestrate coordinated changes in the actin cytoskeleton essential for directed neurite outgrowth and the regulation of synaptic connectivity. Although many details of the cell biology of Rho signaling in the CNS are still unclear, a picture is unfolding showing how mutations that alter Rho signaling result in abnormal neuronal connectivity and deficient cognitive functioning in humans. Conversely, these findings illuminate the cellular mechanisms underlying normal cognitive function.     

Childhood abuse in patients with conversion disorder

OBJECTIVE: Despite the fact that the assumption of a relationship between conversion disorder and childhood traumatization has a long history, there is little empirical evidence to support this premise. The present study examined this relation and investigated whether hypnotic susceptibility mediates the relation between trauma and conversion symptoms, as suggested by Janet's autohypnosis theory of conversion disorder. METHOD: A total of 54 patients with conversion disorder and 50 matched comparison patients with an affective disorder were administered the Structured Trauma Interview as well as measures of cognitive (Dissociative Experiences Scale) and somatoform (20-item Somatoform Dissociation Questionnaire) dissociative experiences. RESULTS: Patients with conversion disorder reported a higher incidence of physical/sexual abuse, a larger number of different types of physical abuse, sexual abuse of longer duration, and incestuous experiences more often than comparison patients. In addition, within the group of patients with conversion disorder, parental dysfunction by the mother-not the father-was associated with higher scores on the Dissociative Experiences Scale and the Somatoform Dissociation Questionnaire. Physical abuse was associated with a larger number of conversion symptoms (Structured Clinical Interview for DSM-IV Axis I Disorders). Hypnotic susceptibility proved to partially mediate the relation between physical abuse and conversion symptoms. CONCLUSIONS: The present results provide evidence of a relationship between childhood traumatization and conversion disorder.