Detection of the third and fourth heart sounds using Hilbert-Huang transform

<p>Abstract</p> <p>Background</p> <p>The third and fourth heart sound (S3 and S4) are two abnormal heart sound components which are proved to be indicators of heart failure during diastolic period. The combination of using diastolic heart sounds with the standard ECG as a measurement of ventricular dysfunction may improve the noninvasive diagnosis and early detection of myocardial ischemia.</p> <p>Methods</p> <p>In this paper, an adaptive method based on time-frequency analysis is proposed to detect the presence of S3 and S4. Heart sound signals during diastolic periods were analyzed with Hilbert-Huang Transform (HHT). A discrete plot of maximal instantaneous frequency and its amplitude was generated and clustered. S3 and S4 were recognized by the clustered points, and performance of the method was further enhanced by period definition and iteration tracking.</p> <p>Results</p> <p>Using the proposed method, S3 and S4 could be detected adaptively in a same method. 90.3% of heart sound cycles with S3 were detected using our method, 9.6% were missed, and 9.6% were false positive. 94% of S4 were detected using our method, 5.5% were missed, and 16% were false positive.</p> <p>Conclusions</p> <p>The proposed method is adaptive for detecting low-amplitude and low-frequency S3 and S4 simultaneously compared with previous detection methods, which would be practical in primary care.</p

Ergonomic principles and techniques in facilitating advanced laparoendoscopic single site (LESS) urinary tract reconstruction with conventional laparoscopic instruments

Background/PurposeThe technical and ergonomic details of laparoendoscopic single site (LESS) reconstruction have not been reported. In this study, we explored the feasibility and safety of performing advanced LESS upper urinary tract reconstruction with conventional laparoscopic instruments.MethodsBetween September 2010 and March 2011, we retrospectively reviewed prospectively collected data from five patients who underwent LESS urinary tract reconstruction. The LESS reconstruction included pyeloureterostomy (N = 1), dismembered pyeloplasty (N = 2), ureteroneocystostomy (N = 1), and ureteroplasty for bifid blind ending ureter (N = 1). The perioperative and postoperative parameters were collected for analysis. The ergonomic principles and techniques are detailed.ResultsAll reconstructive LESS procedures were completed successfully without open conversion or laparoscopic conversion. Ancillary ports or ancillary instruments were not applied in any of the patients. The mean patient age was 40.4 years. The mean operative time was 213 ± 69 minutes, the estimated blood loss ranged from minimal to 50 mL, and the mean hospital stay was 4.4 ± 4 days. No operation-related complication occurred.ConclusionBased on our ergonomic principles and suturing/knotting techniques, conventional laparoscopic instruments are feasible and safe for LESS urinary reconstructive procedures

Quantitative pinch stimulator for exploring evoked nociceptive responses: A pilot study

<p>Abstract</p> <p>Background</p> <p>A mechanical noxious stimulator is useful for studies of pain, both for clinic and basic research. We propose to use a pinch stimulator that can not only generate a quantitative, reproducible noxious pinch but also simultaneously provide a synchronous external trigger signal, which is essential for acquisition of evoked potentials.</p> <p>Methods</p> <p>For ethical considerations, audible and visual aids were incorporated so that pinch force could be regulated within a predetermined level. Reproducibility of the nociceptive responses evoked by this device was validated. The device was constructed with a simple circuit, and the element build-in was delicately selected for the minimum required to produce evoked potentials.</p> <p>Results</p> <p>The magnitude of the force output is linearly proportional to the volts produced by the device (i.e., during the pinch). Increases in force correspond to increases in the number of action potentials induced.</p> <p>Conclusions</p> <p>This device may be useful for studying the mechanisms of nociceptive signal processing in the brain through application of reproducible, noxious pinch stimuli.</p

Endogenous opioid–dopamine neurotransmission underlie negative CBV fMRI signals

Previous studies showed noxious unilateral forepaw electrical stimulation surprisingly evoked negative blood-oxygenation-level-dependent (BOLD), cerebral blood flow (CBF), and cerebral blood volume (CBV) fMRI responses in the bilateral striatum whereas the local neuronal spike and c-Fos activities increased. These negative responses are associated with vasoconstriction and appeared to override the increased hemodynamic responses that typically accompanied with increased neural activity. The current study aimed to investigate the role of μ-opioid system in modulating vasoconstriction in the striatum associated with noxious stimulation on a 4.7-Tesla MRI scanner. Specifically, we investigated: i) how morphine (a μ-opioid receptor agonist) affects the vasoconstriction in the bilateral striatum associated with noxious electrical forepaw stimulation in rats, and ii) how naloxone (an opioid receptor antagonist) and eticlopride (a dopamine D2/D3 receptor antagonist) modulates the morphine effects onwards. Injection of morphine enhanced the negative striatal CBV responses to noxious stimulation. Sequential injection of naloxone in the same animals abolished the stimulus-evoked vasoconstriction. In a separate group of animals, injection of eticlopride following morphine also reduced the vasoconstriction. Our findings suggested that noxious stimulation endogenously activated opioid and dopamine receptors in the striatum and thus leading to vasoconstriction

Differentiation of Schizophrenia Patients from Healthy Subjects by Mismatch Negativity and Neuropsychological Tests

BACKGROUND: Schizophrenia is a heterogeneous disorder with diverse presentations. The current and the proposed DSM-V diagnostic system remains phenomenologically based, despite the fact that several neurobiological and neuropsychological markers have been identified. A multivariate approach has better diagnostic utility than a single marker method. In this study, the mismatch negativity (MMN) deficit of schizophrenia was first replicated in a Han Chinese population, and then the MMN was combined with several neuropsychological measurements to differentiate schizophrenia patients from healthy subjects. METHODOLOGY/PRINCIPAL FINDINGS: 120 schizophrenia patients and 76 healthy controls were recruited. Each subject received examinations for duration MMN, Continuous Performance Test, Wisconsin Card Sorting Test, and Wechsler Adult Intelligence Scale Third Edition (WAIS-III). The MMN was compared between cases and controls, and important covariates were investigated. Schizophrenia patients had significantly reduced MMN amplitudes, and MMN decreased with increasing age in both patient and control groups. None of the neuropsychological indices correlated with MMN. Predictive multivariate logistic regression models using the MMN and neuropsychological measurements as predictors were developed. Four predictors, including MMN at electrode FCz and three scores from the WAIS-III (Arithmetic, Block Design, and Performance IQ) were retained in the final predictive model. The model performed well in differentiating patients from healthy subjects (percentage of concordant pairs: 90.5%). CONCLUSIONS/SIGNIFICANCE: MMN deficits were found in Han Chinese schizophrenia patients. The multivariate approach combining biomarkers from different modalities such as electrophysiology and neuropsychology had a better diagnostic utility

Muscle Force Measurement System for Long-Term Monitoring During

Distraction osteogenesis is a procedure in orthopedics for skeletal lengthening. This operation sometimes causes clinical complications such as paralysis and pain related to the rate and extent of distraction. Therefore, a tension- force monitoring system is mandatory to control optimal lengthening. We developed a portable, low-power consumption system to continuously monitor the distracted tensions during the distraction osteogenesis period on the tibias of four male New Zealand white rabbits. The lengthening rate was 1mm per day at frequencies of once a day in one rabbit, and of three successive steps in the others. The system indicates the distraction measured by force, which is considered to be more physiological in nature rather than by distance. Radiographs were also taken for comparison. The results showed that the system was stable and approximate to being ideal. The measured distract-tension recovered to a steady state faster at the frequency of 1mm a day in three steps, rather than once per day. During the duration of the entire operation, each single lengthening induced more extensive force than that of one-day totals. The integer tension gradually increased until 15 days and tended to be stable. The radiographic examinations also revealed that the tibias healed well after the lengthening; consequently, a dispensable X-ray might be mostly replaced by the system monitoring. This system might be helpful to monitor force measurement for the improvement of distraction osteogenesis

Ultrasound-guided Perineural Vitamin B12 Injection for Peripheral Neuropathy

The objective of this article is to present an innovative treatment for peripheral neuropathy using ultrasound-guided perineural vitamin B12 injection. A 37-year-old patient presented with a progressive dropped foot for 2 months. Preceding trauma was denied. On examination, severe weakness of ankle dorsiflexion was revealed. Ultrasound showed peroneal nerve swelling. Nerve conduction velocity and electromyography study showed results compatible with peroneal neuropathy. Under the diagnosis of peroneal neuropathy, the patient was given 500 μg of methylcobalamin around the peroneal nerve under ultrasound guidance two times, with an interval of 2 weeks. The patient showed improvement of muscle power within 2 weeks. Full muscle power was regained after 3 months. There was no adverse symptom after ultrasound-guided perineural vitamin B12 injection. Ultrasound-guided perineural vitamin B12 has the advantage of precise delivery of high-dose vitamin B12 directly around the defective nerve