Prevalence of human soil-borne nematode infections in Yunnan Province: a cross-sectional study in 2015 / 中国血吸虫病防治杂志

Objective To investigate the current prevalence of human soil-borne nematode infections in Yunnan province, so as to provide the scientific evidence for formulating the soil-borne nematodiasis control strategy in the province. Methods In 2015, a total of 20 survey sites were sampled in 10 counties (cities) of Yunnan Province using the stratified cluster random sampling method. Stool samples were collected from all local permanent residents at ages of one year and older in each survey site, and the soil-borne nematode eggs were identified using the modified Kato-Katz technique and the egg number was counted. In addition, the hookworm species was identified using the filter-paperculture method, and Enterobius vermicularis eggs were detected using the cellophane tape method in children at ages of 3 to 6 years. Results A total of 5 067 residents received stool examinations, and 950 residents were detected with soil-borne nematode infections, with an overall prevalence rate of 18.75%. The prevalence of Ascaris lumbricoides, Trichuris trichura and hookworm was 7.52%, 8.47% and 9.02%, respectively. Among 446 children detected using the cellophane tape method, 5 children were detected with E. vermicularis infections. Among the 160 residents with hookworm infections, there were 139 residents with Necator americanus infections (86.88%), 16 with A. duodenale infections (10.00%) and 5 with mixed infections (3.12%). Mild A. lumbricoides (67.98%, 259/381), T. trichura (88.58%, 380/429) and hookworm infections (94.53%, 432/457) were predominant. Among the four ecological zones, the highest prevalence of human soilborne nematode infections was found in the East Tibet-South Sichuan Ecological Zone (31.79%), and among the 10 survey counties (cities), the greatest prevalence was seen in Gongshan Derung and Nu Autonomous County (50.13%), while the lowest prevalence was found in Ninglang Yi Autonomous County (0.40%). The prevalence of human soil-borne nematode infections was 5.67% (43/759), 26.67% (610/2 287) and 14.70% (297/2 021) in high-, moderate- and low-economic-level regions, respectively. There were no significant differences in the prevalence of human soil-borne nematode infections in terms of ecological regions, survey counties (cities) or economic development levels (χ2 = 342.20, 814.60 and 201.34, all P < 0.05). There was no significantdifference in the prevalence of human soil-borne nematode infections between male (18.21%, 441/2 422) and female residents (19.24%, 509/2 645) (χ2 = 0.89, P > 0.05), and soil-borne nematode infections were detected in residents at all age groups, with the greatest prevalence found in residents at ages of 1 to 9 years (25.88%). In addition, the highest prevalence of soil-borne nematode infections was seen in residents with the Dulong Ethnic Minority (82.09%), in preschool children (25.06%) and in illiterate residents (24.80%), and there was no age-, ethnicity-, occupation- or education level-specific prevalence of soil-borne nematode infections detected (χ2 = 46.50, 1 016.96, 36.33 and 52.43, all P < 0.05). Conclusions The prevalence of human soil-borne nematode infections remains high in Yunnan Province. The management of soil-borne nematodiasis requires to be reinforced among low-age children, farmers, old people and residents with low educations levels or ethnic groups.

Relationship between reference point potential and potential distribution of normal electrocardial field on the thoracic surface of healthy individuals / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the effect of reference point on the potential distribution of normal cardioeleclric field of healthy individuals.</p><p><b>METHODS</b>Two different reference points including central terminal and right forehead were applied to record electrocardiogram simultaneously from 15 testing points (V(1)-V(6), V(7)-V(9), V(3R)-V(8R)) of Wilson lead (RL) and the same testing points (HV(1)-HV(9), HV(3R)-HV(8R)) of head-chest (HC) lead around the torso of healthy individuals. Chi-square test was performed to observe statistical difference between the HCECGs and RLECGs according to different shapes of QRS and T waves.</p><p><b>RESULTS</b>Among 120 healthy individuals, deformed ECGs appeared in V(1) and HV(3R)-HV(8R) leads, with 20% (24/120) inverted T wave in V(1) lead, 100% (120/120) in V(3R)-V(8R) leads, wide or deep Q wave 100% (120/120) in V(4R)-V(8R) leads. However, in the corresponding HC-lead system, T waves were all positive, and QRS waves were upright as the pattern of rs, RS or qRs. There was statistical difference in the form of ECG between V(1), V(3R)-V(8R) of Wilson lead and the corresponding HC-lead (P<0.05). The distribution of normal cardioeleclric field related to QRS-T wave was of all-round outward shape by HC-lead, and of roughly bipolar shape by Wilson lead for inverted QRS-T wave on the right thoracic surface.</p><p><b>CONCLUSION</b>The normal distribution of electrocardial field is determined by the potential of the reference point. The forehead of HC-lead seems to be better than the central terminal as the reference point of the lead system.</p>

Comparison between the head-chest leads electrocardiogram and routine leads in the manifest accessory pathways in patients with Wolff-Parkinson-White syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe whether there was difference between the head-chest leads electrocardiogram (HCECGs) and routine lead electrocardiogram (RLECGs) in the manifest accessory pathways in patients with Wolff-Parkinson-White syndrome.</p><p><b>METHODS</b>HCECGs and RLECGs were recorded simultaneously in patients with Wolff-Parkinson-White syndrome, whose manifest accessory pathways had been confirmed by radiofrequency catheter ablation and intra-cardiac electrophysiology according to the same standard set beforehand. The diagnosis of pathways location was made by analysis of each HCECG and RLECG by two senior physicians in clinical electrophysiology. The diagnostic accuracy of the HCECGs and RLECGs was evaluated by the comparison with that of the intra-cardiac electrophysiology. The delta wave size was also compared between HCECGs and RLECGs.</p><p><b>RESULTS</b>The diagnostic accuracy in the manifest accessory pathways was 86.2% (50/58) in RLECGs, and 84.4% (49/58) in HCECGs in the 58 patients with Wolff-Parkinson-White syndrome, showing no significant difference between them (P > 0.05), but each delta wave in HCECG was more evident than that in RLECG.</p><p><b>CONCLUSION</b>HCECG and RLECG both have high diagnostic accuracy in the manifest accessory pathways in patients with Wolff-Parkinson-White syndrome.</p>

Comparison of head-chest lead electrocardiogram and routine lead electrocardiogram in diagnosis of acute posterior wall myocardial infarction / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the value of head-chest lead electrocardiogram (HCECG) and routine lead electrocardiogram (RLECG) in diagnosis of acute positive posterior myocardial infarction.</p><p><b>METHODS</b>HCECGs and RLECGs were recorded simultaneously in 68 normal individuals and 32 patients with acute posterior wall myocardial infarction confirmed by coronary angiography and echocardiography. Each HCECG and RLECG was analyzed by two senior physicians specialized in clinical electrophysiology who were blinded to the results. The HCECG- and RLECG-based diagnostic results were compared with the results of coronary angiography, and the coincidence rates and false positive rates of diagnosis based on HCECGs and RLECGs were calculated.</p><p><b>RESULTS</b>The coincidence rate was 93.8% (30/32) for RLECGs and 100% (32/32) for HCECGs in the diagnosis of acute posterior wall myocardial infarction, showing no significant difference between them (P>0.05). RLECGs-based diagnosis, however, resulted in a significantly higher false positive rate than HCECGs [13.2% (9/68) vs 0% (0/68), P<0.05].</p><p><b>CONCLUSION</b>Head-chest lead system is superior to routine lead system for its low false positive rates in the diagnosis of acute posterior wall myocardial infarction.</p>

Evaluation of resultant cardiac vector based on voltage distribution of electrocardial field around ex vivo guinea pig heart / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the possibility of resultant cardiac vector of ex vivo guinea pig heart.</p><p><b>METHODS</b>ECGs were recorded in 4 directions on every plane, and in each direction 4 points at different distances from the anterior, posterior, right and left of isolated guinea pig ventricles immersed in normal saline and distilled water.</p><p><b>RESULTS</b>Main upward waves of ECGs were recorded at all points in 4 directions at 3 levels in the two media. The voltage distribution of normal electrocardial field of the QRS wave was of all-round outward shape, which did not match the resultant cardiac vectors between the left and right and between the anterior and posterior ventricular walls.</p><p><b>CONCLUSION</b>There are some confusion and contradiction in the resultant cardiac vector based on the voltage distribution of electrocardial field around ex vivo guinea pig heart.</p>

An efficient method for simulating ventricular electrical activity based on anatomic structure by incorporating AP model / 南方医科大学学报

Conventional medical experiments can hardly simulate cardiac excitation propagation and observe the evolvement of cardiac electrical activities firsthand as is possible with computer simulation. Based on the anatomic structure of the heart, simulation of cardiac electrical activity mainly consists of the emulation of the excitation process among the cardiac cells and calculation of the electrical activities of individual cardiac cells. In this study we establish a geometric ventricular structure model demonstrating the direction of the cardiac muscle fibers and the layers of the ventricular cells, and endow different action potential models to the ventricular cells of different layers, and observe the activation process of the ventricular parts in view of the three-dimensional anatomy. This method gives attention to both enough calculation amounts and efficiency, which achieves satisfactory simulation results of ventricular electrical activity based on the anatomic structure and cell electrophysiology through an improved algorithm on personal computer.