A method to automatically analyze and diagnose ambulatory ECG signals for telemonitoring system / 中国医疗器械杂志

This paper proposes a method of automatic ECG analysis and arrhythmia diagnosis for telemonitoring system. A multi-buffer technique is applied to organize dispersive ECG data. Then, according to second order derivatives of ECG signals, peaks of R waves are automatically detected. Finally, real-time heart rhythm is decided by results of R wave detection. Tests prove that the proposed method is precise, efficient and stable to be applied in real-time ECG telemonitoring system.

A denoising method of epicardial potential mapping signals based on ICA / 中国医疗器械杂志

A new denoising method is presented in the paper, based on the independent component analysis(ICA) and the noise independent component selection measurement which is the dispersivity of the independent component's projection coefficients to each electrode. The results indicate that the method can denoise EPM signals with giving prominence to electrodes' true depolarization signals. So it' s fit well for the EPM system.

The design of the external defibrillator using the truncated exponential biphasic waveform / 中国医疗器械杂志

The external defibrillator is an emergency instrument used very widely in clinics. It plays an important role in rescuing ventricle fibrillation (VF) patients. We have designed an external defibrillator using the truncated exponential biphasic waveform. The system consists of three parts: the ECG collection module, the control module and the defibrillator module. They are introduced respectively, listing the main problems and the methods to solve them. Some experiments have been done and the corresponding results are given.

The application of multilevel B-splines in 3D emulation of dynamic epicardium mapping / 中国医疗器械杂志

This paper presents an algorithm for data interpolation and approximation used in the whole atria mapping. Multilevel B-splines are introduced to compute the whole atria surface through a set of irregularly spaced points and to draw the 3D isopotential map, which can reflect the conduction process of depolarization in complex arrhythmia such as atrial fibrillation.

3D emulation of epicardium dynamic mapping / 中国医疗器械杂志

In order to realize epicardium dynamic mapping of the whole atria, 3-D graphics are drawn with OpenGL. Some source codes are introduced in the paper to explain how to produce, read, and manipulate 3-D model data.

Time-course of mu-calpain activation, c-Fos, c-Jun, HSP70 and HSP27 expression in hypoxic-ischemic neonatal rat brain / 中华儿科杂志

<p><b>OBJECTIVE</b>The cascade of physiological events underlying hypoxic-ischemic brain damage (HIBD) remains to be fully established. The perinatal brain shows both an increased tolerance to hypoxic-ischemic (HI) injury and a faster and more complete recovery than the adult. It is, therefore, important to understand the sequence of events following hypoxia and ischemia in young animals. The present study aimed to clarify the time-course of the activation of the mu-calpain, and the expression of c-Fos, c-Jun, HSP70 and HSP27 proteins following severe HI (2 h hypoxia) and their relationship with each other.</p><p><b>METHODS</b>A modified newborn rat model of HIBD that included a combination of hypoxia and ischemia as described by Rice was used. Forty-two postnatal 7-day-old Sprague-Dawley rats were randomly divided into seven groups (6 rats in each): 6 time-window groups and a normal control group. Samples were collected at 0, 1, 2, 4, 12 and 24 h after HI insults. The protein concentration was determined using a modified Bradford assay. mu-calpain activation, c-Fos, c-Jun, HSP70 and HSP27 expressions were observed respectively by Western blot from cortical and hippocampal samples.</p><p><b>RESULTS</b>The cleavage of cytosolic mu-calpain was observed from both cortical and hippocampal samples in neonatal rats after HI. The ratio 76:80 of mu-calpain was increased significantly post-HI and reached a maximum at 24 h in cortex and at 12 h in hippocampus after HI. The expressions of c-Fos and c-Jun from both cortical and hippocampal samples in neonatal rats were up-regulated and peaked at 2 or 4 h after HI, demonstrating significant differences at 1, 2, 4, and 12 h compared with that observed in the control (P < 0.05). When compared with that observed in cortex, the nuclear c-Fos expression from hippocampal samples was highly elevated at 2, 4 and 12 h but significantly decreased at 24 h after HI (P < 0.05), while the nuclear c-Jun expression from hippocampal samples was highly elevated at 0 and 1 h but significantly decreased at 4 and 24 h after HI (P < 0.05). Similarly, the expressions of HSP70 and HSP27 from both cortical and hippocampal samples were up-regulated and reached a maximum at 12 or 24 h after HI, demonstrating significant differences at 12 or 24 h both in cortex and hippocampus for HSP70, and at 24 h in cerebral cortex as well as at 12 and 24 h in hippocampus for HSP27 compared with the control (P < 0.05). Furthermore, in comparison with that observed in cortex, the HSP70 expression from hippocampal samples was highly elevated at 1 h, but significantly decreased at 4, 12 and 24 h after HI (P < 0.05), while the HSP27 expression was permanently elevated in hippocampus after HI.</p><p><b>CONCLUSION</b>The neuronal injury induced by HI insults appears to involve many ongoing and simultaneous mechanisms. HI activates the calpains immediately, which may contribute to neuron apoptosis, and induces a significant brain neuroprotection, since there is an increased HSP70 expression and a relatively late remarkable HSP27 expression in hypoxic-ischemic neonatal rat brain. Nuclear c-Fos and c-Jun may participate in the pathogenesis of HIBD.</p>

Analysis of gene mutation in patients with tuberous sclerosis complex with polymerase chain reaction-single strand conformation polymorphism / 中华儿科杂志

<p><b>OBJECTIVE</b>Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by unusual tumor-like growth, termed hamartomas that develop in a variety of tissues and organs. Clinical findings characteristic of TSC include facial angiofibroma, epilepsy and mental retardation. In the last decade, two genes (TSC1 and TSC2) responsible for this disease were identified and both of them are speculated to be a kind of tumor suppressor gene. TSC1 and TSC2 are located on 9q34 and 16p13.3, respectively. This study was designed to detect gene mutations in patients with TSC.</p><p><b>METHODS</b>All the exons of TSC1 and TSC2 were analyzed by using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) in DNA separated from peripheral blood of 28 patients with TSC and 100 normal controls. Of the 28 patients, 17 were male and 11 were female, the age of the patients was 1 - 48 years.</p><p><b>RESULTS</b>The mutations were not clustered on a particular exon in either of the genes. Four TSC1 mutations found in 28 cases were on exons (1 nonsense, 2 missense and 1 frameshift); 13 mutations were found in TSC2 gene (2 nonsense, 2 frameshift, 1 deletion and 8 missense). Both TSC1 and TSC2 mutations were detected in 2 cases respectively. The same missense mutation (Q654E) was found in 2 unrelated patients. There was no obvious relationship between the location of the mutation and the clinical symptoms.</p><p><b>CONCLUSION</b>Mutations found in this study were distributed on various exons and there was no clustering of the mutations, the widespread distribution of TSC1/TSC2 mutations hinders the development of a simple diagnostic test, and the identification of individual mutations does not provide prediction of prognosis.</p>