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Y Gang

Publications and source records attributed to Y Gang.

14 recordsLinked to original sources
PubMed2000

A new approach for TU complex characterization.

In this paper, we present a new TU complex detection and characterization algorithm that consists of two stages; the first is a mathematical modeling of the electrocardiographic segment after QRS complex; the second uses classic threshold comparison techniques, over the signal and its first and second derivatives, to determine the significant points of each wave. Later, both T and U waves are morphologically classified. Amongst the principal innovations of this algorithm is the inclusion of U-wave characterization and a mathematical modeling stage, that avoids many of the problems of classic techniques when there is a low signal-to-noise ratio or when wave morphology is atypical. The results of the algorithm validation with the recently appeared QT database are also shown. For T waves these results are better when compared to other existing algorithms. U-wave results cannot be contrasted with other algorithms as, to our knowledge, none are available. Examples showing the causes of principal discrepancies between our algorithm and the QT database annotations are also given, and some ways of attempting to improve and benefit from the proposed algorithm are suggested.

Algorithms↗
PubMed2000

QT dispersion does not represent electrocardiographic interlead heterogeneity of ventricular repolarization.

INTRODUCTION: QT dispersion (QTd, range of QT intervals in 12 ECG leads) is thought to reflect spatial heterogeneity of ventricular refractoriness. However, QTd may be largely due to projections of the repolarization dipole rather than "nondipolar" signals. METHODS AND RESULTS: Seventy-eight normal subjects (47+/-16 years, 23 women), 68 hypertrophic cardiomyopathy patients (HCM; 38+/-15 years, 21 women), 72 dilated cardiomyopathy patients (DCM; 48+/-15 years, 29 women), and 81 survivors of acute myocardial infarction (AMI; 63+/-12 years, 20 women) had digital 12-lead resting supine ECGs recorded (10 ECGs recorded in each subject and results averaged). In each ECG lead, QT interval was measured under operator review by QT Guard (GE Marquette) to obtain QTd. QTd was expressed as the range, standard deviation, and highest-to-lowest quartile difference of QT interval in all measurable leads. Singular value decomposition transferred ECGs into a minimum dimensional time orthogonal space. The first three components represented the ECG dipole; other components represented nondipolar signals. The power of the T wave nondipolar within the total components was computed to measure spatial repolarization heterogeneity (relative T wave residuum, TWR). QTd was 33.6+/-18.3, 47.0+/-19.3, 34.8+/-21.2, and 57.5+/-25.3 msec in normals, HCM, DCM, and AMI, respectively (normals vs DCM: NS, other P < 0.009). TWR was 0.029%+/-0.031%, 0.067%+/-0.067%, 0.112%+/-0.154%, and 0.186%+/-0.308% in normals, HCM, DCM, and AMI (HCM vs DCM: NS, other P < 0.006). The correlations between QTd and TWR were r = -0.0446, 0.2805, -0.1531, and 0.0771 (P = 0.03 for HCM, other NS) in normals, HCM, DCM, and AMI, respectively. CONCLUSION: Spatial heterogeneity of ventricular repolarization exists and is measurable in 12-lead resting ECGs. It differs between different clinical groups, but the so-called QT dispersion is unrelated to it.

Adult↗
PubMed1998

Computerised measurements of QT dispersion in healthy subjects.

OBJECTIVE: To assess the stability and reproducibility of computerised QT dispersion (QTd) measurement in healthy subjects, as this is presently being incorporated into commercial electrocardiographic systems. METHODS: 70 healthy volunteers (mean (SD) age 38 (10) years, 35 men, 35 women) with a normal 12 lead electrocardiogram (ECG) were studied. From each subject, 70 ECG recordings were taken using the MAC VU ECG recorder (Marquette). In study A, 50 ECGs were recorded in each subject: 10 supine, 10 sitting, 10 standing, 10 holding breath in maximum inspiration, and 10 holding breath in maximum expiration. After a mean interval of 8 (3) days (range 7 to 23), 10 recordings in supine and 10 in the standing position were repeated in each subject (study B). On measurements made using a research version of the commercial software without manual modification, the reproducibility of QTd was assessed by coefficient of variance (CV) and relative error, and comparisons made with other ECG indices. RESULTS: (1) QTd measurements were stable and not influenced by changes in posture and respiratory cycle; (2) there was no difference in QTd measurements between men and women, or between age groups dichotomised at 35 years; (3) no correlation was found between QTd and heart rate or QT interval; (4) short term reproducibility of all QTd measurements (CV 15.6% to 43.8%) was worse than that of conventional ECG indices (CV 1.4% to 5.3%); (5) long term reproducibility of QTd measurements (relative error 27.4% to 31.0%) was also worse than that of conventional ECG indices (relative error 1.8% to 7.9%) (p < 0.0001); (6) the reproducibility of QTd measurements tended to increase when several serial recordings were averaged. CONCLUSIONS: Computerised measurements of global QTd and global QT-SD from 12 lead ECG by the MAC VU/QT Guard system are not significantly altered by changes in posture and respiration. The reproducibility of all QTd measurements is inferior to that of conventional ECG indices in healthy subjects.

Adolescent↗
PubMed1995

What is the desirable stimulus to induce the rectoanal inhibitory reflex?

PURPOSE: This study was designed to find other methods to induce rectoanal inhibitory reflex. METHODS: Twenty healthy children were studied manometrically using three different types of stimuli, air, balloon, and water. RESULTS: Reflex occurred with all three kinds of stimuli; however, the free-air method was more sensitive and convenient than the common inflating balloon method. The lowest feeling amount and lowest amount in the free-air method are significantly lower than those in the balloon method (P < 0.05). The highest amount in the free-air method is significantly lower than those in the balloon method (P < 0.02). The highest drop and sustain time in both the free-air and balloon methods are not significant. CONCLUSIONS: The internal and sphincter has the function to respond to air (flatus). The semiconductor strain gauge catheter is better than the air-filled or water-filled balloon and water-infused catheter for the study of rectal physiology.

Adolescent↗
PubMed1995

Familial dilated cardiomyopathy in the United Kingdom.

OBJECTIVES: To determine the frequency and mode of inheritance of familial dilated cardiomyopathy in the United Kingdom. BACKGROUND: Two recent prospective studies have suggested that familial forms of dilated cardiomyopathy are common but have been limited by selective screening methods, inadequate diagnostic criteria, and low rates of ascertainment. METHODS: Prospective screening study of 236 relatives from 40 families of patients with dilated cardiomyopathy. Screening consisted of clinical examination, 12 lead electrocardiogram, and two-dimensional Doppler echocardiography. Relatives with systemic hypertension and other cardiac diseases were excluded from the study. All echocardiograms were performed by an experienced echocardiographer who was blinded to clinical information. Relatives were classified as having dilated cardiomyopathy, left ventricular enlargement (method of Henry), depressed fractional shortening, or as being normal. Relatives with abnormal investigations underwent further evaluation as appropriate. RESULTS: Twenty five cases of dilated cardiomyopathy were identified and came from 10 (25%) of the 40 families screened. Pedigree analysis was most consistent with autosomal dominant inheritance and variable penetrance (65-95%). Of the remaining apparently healthy relatives, 37 (18%) were found to have left ventricular enlargement and nine (4%) depressed fractional shortening; these values were significantly higher than those observed in 239 healthy controls (24 (10%), P = 0.02 and one (0.4%), P = 0.01, respectively). CONCLUSIONS: Patients with dilated cardiomyopathy commonly have an affected family member and a high proportion of apparently healthy relatives with minor echocardiographic abnormalities. Segregation analysis suggests that familial dilated cardiomyopathy is the result of the transmission of a rare autosomal dominant gene. Further studies are currently underway to characterise the molecular basis of familial dilated cardiomyopathy and identify early disease within these families.

Adolescent↗
PubMed1994

Adjustment of QT dispersion assessed from 12 lead electrocardiograms for different numbers of analysed electrocardiographic leads: comparison of stability of different methods.

OBJECTIVE: Normal electrocardiographic recordings were analysed to establish the influence of measurement of different numbers of electrocardiographic leads on the results of different formulas expressing QT dispersion and the effects of adjustment of QT dispersion obtained from a subset of an electrocardiogram to approximate to the true QT dispersion obtained from a complete electrocardiogram. SUBJECTS AND METHODS: Resting 12 lead electrocardiograms of 27 healthy people were investigated. In each lead, the QT interval was measured with a digitising board and QT dispersion was evaluated by three formulas: (A) the difference between the longest and the shortest QT interval among all leads; (B) the difference between the second longest and the second shortest QT interval; (C) SD of QT intervals in different leads. For each formula, the "true" dispersion was assessed from all measurable leads and then different combinations of leads were omitted. The mean relative differences between the QT dispersion with a given number of omitted leads and the "true" QT dispersion (mean relative errors) and the coefficients of variance of the results of QT dispersion obtained when omitting combinations of leads were compared for the different formulas. The procedure was repeated with an adjustment of each formula dividing its results by the square root of the number of measured leads. The same approach was used for the measurement of QT dispersion from the chest leads including a fourth formula (D) the SD of interlead differences weighted according to the distances between leads. For different formulas, the mean relative errors caused by omitting individual electrocardiographic leads were also assessed and the importance of individual leads for correct measurement of QT dispersion was investigated. RESULTS: The study found important differences between different formulas for assessment of QT dispersion with respect to compensation for missing measurements of QT interval. The standard max-min formula (A) performed poorly (mean relative errors of 6.1% to 18.5% for missing one to four leads) but was appropriately adjusted with the factor of 1/square root of n (n = number of measured leads). In a population of healthy people such an adjustment removed the systematic bias introduced by missing leads of the 12 lead electrocardiogram and significantly reduced the mean relative errors caused by the omission of several leads. The unadjusted SD was the optimum formula (C) for the analysis of 12 lead electrocardiograms, and the weighted standard deviation (D) was the optimum for the analysis of six lead chest electrocardiograms. The coefficients of variance of measurements of QT dispersion with different missing leads were very large (about 3 to 7 for one to four missing leads). Independently of the formula for measurement of QT dispersion, omission of different leads produced substantially different relative errors. In 12 lead electrocardiograms the largest relative errors (> 10%) were caused by omitting lead aVL or lead V1. CONCLUSIONS: Because of the large coefficients of variance, the concept of adjusting the QT dispersion for different numbers of electrocardiographic leads used in its assessment is difficult if not impossible to fulfil. Thus it is likely to be more appropriate to assess QT dispersion from standardised constant sets of electrocardiographic leads.

Adult↗
PubMed1993

[Clinical evaluation of a lung cancer-associated protein antigen, cytokeratin 19 fragment: I. Radioimmunoassay and its fundamental character for clinical laboratory measurement].

Serum level of cytokeratin 19 fragment; which is a tumor associated antigen of lung cancer; was detected by the radioimmunometric assay. Reliability for clinical laboratory measurement was investigated. Detective range of cytokeratin 19 fragment was 0-50 ng/ml and the results including reproducibility, linearity of the data from diluted standard samples, was good enough for laboratory practice use. Although, influence of high concentration of CA19-9 over cytokeratin 19 fragment assay was suspected, there was no correlation between amount of added the antigen to data of cytokeratin 19 fragment. So direct cross reactivity of cytokeratin 19 fragment antibody to CA19-9 seemed less possible. As inhibitory effect of samples which contained over 100 ng/ml of cytokeratin 19 fragment on assay was observed due to antigen excess, evaluation by diluted sample was necessary for the samples that showed over detective limit.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1993

[Clinical evaluation of a lung cancer-associated protein antigen, cytokeratin 19 fragment: II. Radioimmunoassay and effect of aging and smoking over serum level of normal individuals].

Serum level of cytokeratin 19 fragment which is a tumor associated antigen of lung cancer was detected by the radioimmunometric assay. Effect of smoking and of aging on serum reference value was analyzed over 331 normal individuals. Serum cytokeratin 19 fragment level of smokers, mean 0.89ng/ml, was higher than that of non-smokers, mean 0.70ng/ml although there was no statistical meaning over the difference. And there was tendency to increase of cytokeratin 19 fragment level with aging. Mean + 2SD of cytokeratin 19 fragment of normal was 2.17ng/ml. Clinico-epidemiological specificity of cytokeratin 19 fragment on normal individuals was discussed.

Adult↗
PubMed1990

[An epidemiological survey of gallstones with gray-scale ultrasound].

Gray-scale real-time ultrasound has been employed to investigate gallstone with a positive result of 553 cases out of 15,856 healthy subjects in city and countryside, the incidence being 34.88%. The feature of incidence is as follows: 1. The incidence of the simple gallbladder stone is more common than that of the other sites (male is about 81.15%, female is about 87.29%); 2. The incidence of gallstones of city residents is higher than that of the country people with significant difference statistically (P less than 0.01); 3. The incidence of gallstone in female city residents is higher than male, about 2.5:1, which shows significant difference. (P less than 0.01); 4. The incidence of gallstones in female city residents is higher than in countryside (P less than 0.01); 5. There is no significant difference in the incidence of gallstone between male and female in the countryside (P greater than 0.05); 6. There is no significant difference in the incidence of gallstones between city male and the male in the countryside (P greater than 0.05); 7. Either in the city or in the countryside, it has been shown that there is a tendency of increasing incidence of gallstone with age in both sexes (P less than 0.01). The relationship between the gallstone and the clinical symptoms has been discussed in this paper.

Adolescent↗
PubMed1985

[CA 15-3 is present as a novel tumor marker in the sera of patients with breast cancer and other malignancies].

As a novel tumor marker, we employed a quantitative sandwich RIA system utilizing two monoclonal antibodies (115D8, DF3) which react with a circulating antigen expressed by human breast cancer cells. The optimum condition for this assay was found be a 60 minute incubation at 37 degrees C for the first reaction and a 60 minute one at 25 degrees C for the second reaction. Under these optimum conditions, intra-assay variation of control sera was CV 3.6% and inter-assay variation was CV 6.6%. The observed range of CA 15-3 concentration in 75 healthy persons was 7.5 +/- 3.4 units/ml (mean +/- SD) and mean +2 SD was 14.2 U/ml. Less than 15 U/ml was decided as the cut off level. The positive rate in 113 patients with benign diseases was 18%, the serum levels being less than 25 U/ml. Increased CA 15-3 levels in sera of 178 patients were found respectively, in 0%, 41%, 45%, 50% and 75% of stage I, II, III, IV in primary breast cancer and advanced breast cancer. The sera of 10 patients with advanced breast cancer were collected regularly during a 2 to 4 month period. All patients with PD showed increased CA 15-3 levels and four patients in PR showed a clear decrease of serum levels. In 167 other malignancies, increased levels were found in 76%, 63%, 58%, 33%, 32% and 22% of the sera from uterine, pancreatic, ovarian, prostatic, lung and gastric carcinomas. The data revealed that serum CA 15-3 was clinically useful as a tumor marker especially a monitoring marker of advanced breast cancer, but presently the assay is not suitable for the early detection of breast tumors. Also its measurement seemed to be useful in ovarian cancer, uterine cancer, pancreatic cancer and adenocarcinoma of the lung.

Antigens, Neoplasm↗
PubMedDate not supplied

Expression of leukemia-inhibitory factor as an autocrinal growth factor in human medulloblastomas.

Medulloblastoma is the most frequent pediatric brain tumor, with the capacities of rapid proliferation and intracranial dissemination. However, the factor(s) regulating medulloblastoma growth has not yet been well characterized. Leukemia-inhibitory factor (LIF) and interleukin-6 (IL-6) play different roles in the formation/progression of various embryonic and pediatric tumors, but their biological effects on medulloblastoma cells are less well known. Therefore, in vivo and in vitro expression of LIF, IL-6 and their signal transducer genes encoding LIF receptor (LIFR), IL-6 receptor (IL-6R) and gp130 in human medulloblastoma cells were investigated by multiple cellular and molecular biology approaches. The results revealed that LIF expression could be found in 26 out of 28 tumors/cell line and over 90% of the samples expressed LIFR, IL-6R and gp130. In contrast, none of the samples showed IL-6 expression. An established medulloblastoma cell line, Med-3, was used to evaluate the potential effects of LIF and IL-6 on the proliferation of medulloblastoma cells. The growth of Med-3 cells was efficiently inhibited either by anti-LIF antibody or by antisense LIF oligonucleotide. Addition of exogenous human recombinant IL-6 could dramatically enhance Med-3 cell outgrowth. Our data thus for the first time demonstrated the important role of LIF as an autocrinal and IL-6 as a paracrinal growth factor in the proliferation of medulloblastoma cells.

Blotting, Southern↗