Validating an automated sleep spindle detection algorithm using an individualized approach

The goal of the current investigation was to develop a systematic method to validate the accuracy of an automated method of sleep spindle detection that takes into consideration individual differences in spindle amplitude. The benchmarking approach used here could be employed more generally to validate automated spindle scoring from other detection algorithms. In a sample of Stage 2 sleep from 10 healthy young subjects, spindles were identified both manually and automatically. The minimum amplitude threshold used by the prana ^® (PhiTools, Strasbourg, France) software spindle detection algorithm to identify a spindle was subject‐specific and determined based upon each subject’s mean peak spindle amplitude. Overall sensitivity and specificity values were 98.96 and 88.49%, respectively, when compared to manual scoring. Selecting individual amplitude thresholds for spindle detection based on systematic benchmarking data may validate automated spindle detection methods and improve reproducibility of experimental results. Given that interindividual differences are accounted for, we feel that automatic spindle detection provides an accurate and efficient alternative approach for detecting sleep spindles.     

The Clinical Use of External Noninvasive Pacing in the Termination of Sustained Ventricular Tachycardia

In order to evaluate the potential use of external cardiac pacing (EXP) in the clinical termination of sustained ventricular tachycardia (VT), we attempted VT terminations in seven patients. All had recurrent sustained monomorphic ventricular tachycardia (mean rate 145 beats/min), which had previously required cardioversion. During subsequent VT episodes, all seven underwent overdrive pacing with EXP at a pulse amplitude of 120 mA, and rates of 200 pulses/min. A total of 18 of 18 episodes of VT were successfully terminated by EXP alone. In one patient, the first attempt at EXP termination of one episode of VT resulted in an acceleration of the tachycardia, which was then terminated by EXP. All patients tolerated EXP well with minimal sedation. We conclude that EXP may be an effective clinical modality for the termination of sustained monomorphic ventricular tachycardia.     

Outpatient Electrical Cardioversion of Atrial Fibrillation: 8 Years' Experience. Analysis of Shock-Related Arrhythmias

Background: Outpatient electrical cardioversion (EC) of atrial fibrillation is currently the standard of care. Shock-related arrhythmias may be particularly deleterious in this setting. Preoperative identification of high-risk patients may be very useful.
Methods: A retrospective analysis was made of 543 consecutive elective EC procedures in 457 outpatients over an 8-year period in a university cardiological institute. The protocol included adequate anticoagulation, intravenous anesthesia, direct current shock, and a direct observation after a shock to detect procedure-related complications. No patients were excluded due to severity of pathology or comorbidities. Clinical characteristics, energy delivered, medications, arrhythmic phenomena, and predictors of success and complications were analyzed.
Results: Of 543 ECs performed, 88.2% restored sinus rhythm, which persisted at discharge in 83.2%. No anesthesia-related complications were detected. No thromboembolic complications were detected. Use of a biphasic cardioverter was the only predictor of success (P = 0.0001). The bradyarrhythmic complication rate was 1.5%. No ventricular arrhythmic events were detected. Atrial flutter was present in five of eight patients who developed complications versus 44 of 535 patients who had no complications (P < 0.0005), and prosthetic heart valves in four of eight complicated versus 40 of 535 uncomplicated cases (P = 0.0044). The combination of atrial flutter and prosthetic heart valve was found in four of eight complicated versus 11 of 535 uncomplicated cases (P < 0.0005).
Conclusion: Shock-related arrhythmias are essentially bradyarrhythmias. Atrial flutter and previous cardiac surgery identify a subgroup of patients at high risk of postshock bradyarrhythmic complications.     

An outbreak of pneumonia associated with S. pneumoniae at a military training facility in Finland in 2006

Streptococcus pneumoniae is a well‐known cause of community‐acquired bacterial pneumonia. The purpose of this study was to assess the cause and extent of the outbreak of pneumonia which occurred among military recruits following a 1‐week hard encampment in Finland. We also assessed the carriage rate and molecular characteristics of the S. pneumoniae isolates. All pneumococcal isolates were studied for antibiotic susceptibility, serotyped, genotyped by multilocus sequence typing (MLST), and the presence of pneumococcal rlrA pilus islet was detected. The genotype results defined by MLST corresponded with the serotype results. S. pneumoniae serotype 7F, ST2331, seemed to be associated with an outbreak of pneumonia and nasopharyngeal carriage among 43 military recruits. Of the 43 military recruits, five (12%) were hospitalized with pneumonia and two (40%) of them were positive for S. pneumoniae serotype 7F, ST2331 by blood culture. Eighteen (42%) of the 43 men were found to be positive for S. pneumoniae by nasopharyngeal culture, and nine (50%) of them carried pneumococcal serotype 7F, ST2331. The outbreak strain covered 55% of all the pneumococcal findings. Outbreaks of invasive pneumococcal disease seem to occur in a crowded environment such as a military training facility even among previously healthy young men.     

Hypertrophic Scarring is the Usual Outcome of Non-Membranous Aplasia Cutis of the Scalp

Abstract:  The outcome of aplasia cutis congenita of the scalp, nonmembranous type, in a series of 21 Caucasian patients is reported. In all the patients the congenital skin defect healed with irregular hypertrophic scar formation.     

Maternal supplementation and bone growth in infancy

Summary. The effects of maternal supplementation during pregnancy and lactation on bone growth of infants were investigated in 272 mother-infant pairs who participated in the Guatemalan Longitudinal Study of Nutritional Supplementation, Growth and Development. Mothers received one of two nutritional supplements according to village of residence, and bone growth was determined from dimensions of the second metacarpal measured directly from hand-wrist radiographs of 3-month-old infants. Multiple regression analyses indicated significant supplementation effects on cortical bone dimensions related to the volume of supplement intake. These findings were independent of maternal characteristics and attendance at the supplementation centres, and the infant's gender, size, gestational age and morbidity experience. The nutrient composition of the supplements and the patterns of the supplementation effects eliminate proteins, energy, calcium and phosphorus as the nutrients potentially responsible for the bone-specific response. Candidate nutrients for the observed effects are vitamin A, ascorbic acid, niacin, thiamin, iron or fluorine. Presumptive evidence suggests the effects may be due to vitamin A supplementation. These findings suggest opportunities for nutritional intervention in pregnancy and the early postpartum period to prevent osteopaenia in infancy.     

Specific Antibody Responses to Subtilisin Carlsberg (Alcalase) in Mice: Development of an Intranasal Exposure Model

An intranasal (i.n.) dosing model was developed in mice as apotential alternative to more difficult, time-consuming, andcostly guinea pig intratracheal (GPIT) or mouse intratrachealmodels for assessment of the respiratory immunogenicity of detergentenzymes. Using a benchmark enzyme, Alcalase (protease subtilisinCarlsberg), studies were conducted to standardize the modelin terms of mouse strain, dosing and serum harvest regimen,and the primary immunoglobulin endpoint to use. The primaryassay endpoint selected was the enzyme-specific IgG1 titer determinedby an Alcalase-specific ELISA. This is not the primary allergenicantibody in mice (IgE is); however, IgG1 is coregulated withIgE via the IL-4/TH2 pathway and may have a role in mediatingallergic-type responses. BDF1 mice (C57B1/6 x DBA/2) were selectedas representative of high responder strains, with high responseassociated with the H-2^b (C57B1/6) parent. The dosing regimenused for most studies incorporated three i.n. exposures (Days1, 3, and 10) and bleeding of the animals on Day 15. The animalswere anesthetized and then immunized by allowing them to inhale5-µl aliquots of dosing solution into each nostril ateach immunization. Positioning of the animals with their headsdown (vs up) may have allowed more of the dosing solution toremain in the nasal region for a slightly longer period of time,but did not change the eventual GI tract migration and excretionof each dose. The presence of a detergent matrix in the enzymedosing solution enhanced the IgG1 response. Immunizing withenzyme plus detergent gave highly consistent dose-response curvesfor Alcalase when evaluated over many studies. An enzyme-specificallergic antibody (IgE) response was weak and inconsistent underthe dosing regimen used to generate the IgG1 response, but wasstronger with longer-term dosing, consistent with the delayin IgE vs IgG1 responses seen in some other studies. Using IgG1as a surrogate for allergic sensitization, we have preliminarydata showing similar differential potencies between Alcalaseand other test enzymes as detected in previous GPIT tests. Onthe basis of these data, we believe the i.n. immunization/IgG1response model is a robust technique that may be useful in determiningthe relative immunogenicities of detergent enzymes and otherproteins.