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Biomedical subjects

X Xue

Publications and source records attributed to X Xue.

33 records · Page 2Linked to original sources
PubMed1999

[TCD functional test for vertigo induced by ischemic cerebrovascular disorders].

OBJECTIVE: To diagnose differentially the vetigo induced by some ischemic cerebrovascular disorder. METHOD: Patients with vertebrobasilar artery transient ischemic vertigo (group A), migraine (group B), hyperventilation syndrome (group C), hypertension (group D) are measured by using TCD functional examination which included blood peak velocity of systolic (Vs) and diastolic (Vd) end-period of vertibrobasilar artery of routine TCD (TCD-R), one minute hyperventilation TCD (TCD-HV) and one minute voluntary apnea TCD (TCD-B) respectively. RESULT: It showed that the Vs, Vd are decreased under the three conditions in A, B and D groups. The most apparent decrease are obversed in D group. The values of the decrease are similar between group A and B. No changes are found in C group. The abnormal Vs incidences of TCD-B measurement in group A are higher than those in group B and C, but significant lower than those in group D; and in TCD-HV test lower than group D and C, higher than group B; in TCD-R test, lower than group D, and no difference with group B and C. The abnormal incidences of Vd in group A are lower than group D and higher than group B in TCD-B test. In TCD-HV test, the group A abnormol incidences are lower than group D but higher than group B and C. In TCD-R test, the abnormal incidences are lower than group D and no difference between group B and C. CONCLUSION: The TCD measuremen is useful for differential diagnosis of vertigo induced by ischemic cerebrovascular disorders.

Brain Ischemia↗
PubMed1997

Regression analysis of discrete time survival data under heterogeneity.

This paper concerns the regression analysis of discrete time survival data for heterogeneous populations by means of frailty models. We express the survival time for each individual as a sequence of binary variables that indicate if the individual survived at each time point. The main result is that the likelihood for these indicators can be factored into contributions that involve the conditional survival probabilities integrated over the frailty distribution of the risk set (population-averaged). We then model these population-averaged conditional probabilities as a function of covariates. The result justifies the practice of treating the failure indicators as independent Bernoulli trials and fitting binary regression models for the conditional failure probabilities at each time point. However, we must interpret the regression coefficients as population-averaged rather than subject-specific parameters. We apply the method to the Framingham Heart Study on risk factors for cardiovascular disease.

Algorithms↗
PubMed1997

Application of color Doppler ultrasonic examination in deep vein valvular incompetence in lower limbs.

By use of color Doppler Flow Imaging (CDFI), the morphologic and hemodynamic parameters such as the diameters of femoral and popliteal veins, blood flow velocity and the reflux of valve area were examined in lower extremity deep valvular incompetence (DVI) and normal control groups. The purpose was to evaluate the value of CDFI in the diagnosis of DVI. The results demonstrated that the parameters between the two groups had a very significant difference (P < 0.001), indicating that the CDFI is non-invasive, cost-effective and safe and it might serve as a practical tool in the diagnosis of lower extremity deep valvular incompetence.

Adult↗
PubMed1997

Neighborhood risk factors for low birthweight in Baltimore: a multilevel analysis.

OBJECTIVES: Past research on low birthweight has focused on individual-level risk factors. We sought to assess the contribution of macrolevel social factors by using census tract-level data on social stratification, community empowerment, and environmental stressors. METHODS: Census tract-level information on social risk was linked to birth certificate records from Baltimore, Md, for the period 1985 through 1989. Individual level factors included maternal education, maternal age, medical assistance health insurance (Medicaid), and trimester of prenatal care initiation. Methods of multilevel modeling using two-stage regression analyses were employed. RESULTS: Macrolevel factors had both direct associations and interactions with low birthweight. All individual risk factors showed interaction with macrolevel variables; that is, individual-level risk factors for low birthweight behaved differently depending upon the characteristics of the neighborhood of residence. For example, women living in high-risk neighborhoods benefited less from prenatal care than did women living in lower-risk neighborhoods. CONCLUSIONS: Multilevel modeling is an important tool that allows simultaneous study of macro- and individual-level risk factors. Multilevel analyses should play a larger role in the formulation of public health policies.

Baltimore↗
PubMed1997

[Peri-operative death in patients undergone lung cancer resection].

OBJECTIVE: To ascertain the causes of peri-operative death in patients with lung cancer. METHODS: Five cases died in the peri-operative period in 174 lung cancer patients undergone resection were analyzed. RESULTS: Two cases died from pulmonary edema and/or atelectasis; one died from acute myocardial infarction and ventricular fibrillation; one had sudden death immediately after withdrawal of endotracheal tube; the other one died of brain matastasis and multiple organ failure. CONCLUSION: Cardio-pulmonary complications are the major causes of peri-operative death in lung cancer patients. Appropriate preventive meassures should be taken to reduce operative mortality.

Adenocarcinoma↗
PubMed1997

[Purification of hemagglutinin of hemorrhagic fever with renal syndrome virus by high pressure liquid chromatography and analysis of immunogenicity].

The brains of suckling mice and suspension of Vero-E6 cells inoculated with Chen's strain of hemorrhagic fever with renal syndrome virus (HFRSV) were obtained and prepared into high titre hemagglutinin (HAN). The crude HAN was purified by high pressure liquid chromatography. The molecular weight of the purified HAN is 56600 and has higher titre of hemagglutinin activity. It has been proved that the purified HAN has homogeneous molecular weight and buoyant density through SDS-PAGE and sucrose gradient ultracenrifugation. Nine monoclonal antibodies (McAb) from varions HFRS virus have been used for analyzing the epitope of purified HAN by ELISA. It was demonstrated that the purified HAN has epitopes of hemagglutinin and neutralizing antigens. The Balb/C mice could be induce specific antibody against HFRSV by immunization with purified HAN. The titre of neutralization was 40 and titre of hemagglutinin inhibition was 64. Some problems concerning the HAN of HFRS virus were discussed.

Animals↗
PubMed1996

Bivariate frailty model for the analysis of multivariate survival time.

Because of limitations of the univariate frailty model in analysis of multivariate survival data, a bivariate frailty model is introduced for the analysis of bivariate survival data. This provides tremendous flexibility especially in allowing negative associations between subjects within the same cluster. The approach involves incorporating into the model two possibly correlated frailties for each cluster. The bivariate lognormal distribution is used as the frailty distribution. The model is then generalized to multivariate survival data with two distinguished groups and also to alternating process data. A modified EM algorithm is developed with no requirement of specification of the baseline hazards. The estimators are generalized maximum likelihood estimators with subject-specific interpretation. The model is applied to a mental health study on evaluation of health policy effects for inpatient psychiatric care.

Algorithms↗
PubMed1995

Violence by male partners against women during the childbearing year: a contextual analysis.

OBJECTIVES: Many contextual analyses that bridge the micro-level-macro-level gap in identifying risk factors for adverse outcomes have not used methods appropriate for multilevel data. The purpose of this paper is to illustrate the application of appropriate multi-level analytic methods and discuss their implications for public health. METHODS: A previously published individual-level model of physical violence perpetrated by male partners during the childbearing year was reanalyzed to include variables describing the neighborhoods where the women resided. Logistic regression with estimation methods of the generalized estimating equation was used for the contextual analysis. To assess the advantages of the generalized estimating equation over conventional logistic regression, both were used for the two-level model. RESULTS: The regression coefficients from the contextual model differed from the betas obtained in the individual-level model. Not only were neighborhood-level variables related to the risk of partner-perpetrated violence, but the presence of these macro-level variables in the models modified the relationships of the individual-level variables to the risk of violence. CONCLUSIONS: Two-level models that include individual- and community-level factors may be beneficial for purposes of explanation in public health research.

Adolescent↗
PubMed1995

[Experimental study of survival mechanism of skin flap with subdermal vascular rete].

AIM: To determine the blood supply style and survival mechanism of skin flap with subdermal vascular rete. MATERIAL AND METHODS: The skin flap on trunk of piglets were taken as experimental pattern. The survival length of skin flap was examined and the nuclear element distribution in the skin flap was determined by ECT. RESULTS AND CONCLUSION: This study demonstrated that the distal portion of super-long flap with subdermal vascular rete fail to getting blood supply from its pedicle. This kind of flap is actually a combination of flap and free graft with subdermal vascular rete. This kind of super-long and super-wide flap is actually not a flap but a free skin graft. The survival of super-long and super-wide flaps with subdermal vascular rete rely on the blood supply from the wounds and their edges partially or completely. Their survival style is actually free grafting.

Animals↗
PubMed1994

Interpersonal conflict and physical violence during the childbearing year.

Reducing physical abuse directed at women by male partners is one of the nation's Year 2000 health objectives. An important target group for achieving this health objective is pregnant women. The present study examines the frequency, severity, perpetrators and psychosocial correlates of violence during the childbearing year. A panel of 275 women were interviewed 3 times during pregnancy and at 6 months postpartum. Moderate or severe violence was somewhat more common during the postpartum period than during the prenatal period--19% of women reported experiencing moderate or severe violence prenatally, compared to 25% in the postpartum period. For partner-perpetrated violence, being better educated was associated with increased risk of violence as was having had a sex partner who ever shot drugs; being older, having a confidant and having social support from friends were significant protective factors. For violence perpetrated by someone other than a male partner, having a confidant was a significant protective factor. Obstetric care providers who routinely come in contact with pregnant women, as well as emergency department staff, need to be systematically screening for violence against women. Efforts to enhance women's social support networks should be included in primary and secondary prevention programs.

Adolescent↗
PubMed1992

[Effects of fertilization on yield of Asparagus cochinchinensis (Lour.) Merr].

The experiment revealed that the use of various kinds of fertilizers has apparent effect on the yield of Asparagus cochinchinensis during its growth period. Nitrogen fertilizer and compound fertilizer are suitable for the seeding period, while compound fertilizer, phosphorus and potassium fertilizers are suitable for the period of root forming. The quantity of fertilizer to be used depends on the growing and soil conditions.

Fertilizers↗
PubMed1990

[Determination of water soluble silicon from herbal drugs].

This article has set up a method for silicon determination by ammonium molybdate-ferrous sulfate-sodium carbonate spectrophotometry. The method is simple, convenient, quick, effective and free of the influence of phosphate ion and reducing agents such as vitamin C and so on. By this method water soluble silicon has been determined in 38 herbal drugs.

Drugs, Chinese Herbal↗
PubMedDate not supplied

Sensitive biomarker of polycyclic aromatic hydrocarbons (PAHs): urinary 1-hydroxyprene glucuronide in relation to smoking and low ambient levels of exposure.

The study was conducted in a Chinese population with occupational or environmental exposures to polycyclic aromatic hydrocarbons (PAHs). A total of 106 subjects were recruited from coke-oven workers (workers), residents in a metropolitan area (residents) and suburban gardeners (gardeners). All subjects were monitored twice for their personal exposures to PAHs. The biological samples were collected for measurements of 1-hydroxypyrene (1-OHP) and cotinine in urine. The geometric means of personal exposure levels of pyrene, benz(a)anthracene (BaA) and benzo(a)pyrene (BaP) in workers were 1.470, 0.978 and 0.805 microg m-3, respectively. The corresponding levels in residents were 0.050, 0.034 and 0.025 microg m-3; and those in gardeners were 0.011, 0.020 and 0.008 microg m-3, respectively. The conjugate of 1-OHP with glucuronide (1-OHP-G) is the predominant form of pyrene metabolite in urine and it showed strong associations with exposures not only to pyrene, but also to BaA, BaP and total PAHs. Most importantly, a significant difference in 1-OHP-G was even detected between the subgroups with exposures to BaP at < 0.010 and > 0.010 but < 0.020 microg m-3, suggesting that 1-OHP-G is a good marker that can be used for the risk assessment of BaP exposure at levels currently encountered in ambient air. Furthermore, multiple regression analyses of 1-OHP-G on PAHs exposure indicated that cigarette smoke was a major confounding factor and should be considered and adjusted for while using 1-OHP to estimate PAHs exposure.

Air Pollutants↗
PubMedDate not supplied

Tamoxifen and genistein synergistically down-regulate signal transduction and proliferation in estrogen receptor-negative human breast carcinoma MDA-MB-435 cells.

PURPOSE: Tamoxifen and genistein were tested for synergism in estrogen receptor- negative human breast carcinoma MDA-MB-435 cells because the two compounds decrease signal transduction activity through different biochemical mechanisms and arrest the cell cycle at different phases. MATERIALS AND METHODS: The combination effect of tamoxifen and genistein on signal transduction was determined by measuring IP3 concentrations and on cell proliferation and colony formation by growth inhibition assay and clonogenic assay. RESULTS: In growth inhibition assays, for tamoxifen and genistein in the carcinoma cells the IC50s were (mean +/- SE) 17 +/- 0.9 and 27 +/- 1.6 microM; in clonogenic assays the LC50s were 0.9 +/- 0.4 and 12.5 +/- 1.1 microM, respectively. When tamoxifen and genistein were simultaneously added to the cells, synergism was observed in growth inhibition, in cytotoxicity and in the reduction of inositol 1,4,5-trisphosphate concentration. CONCLUSION: The synergistic down-regulation of signal transduction by tamoxifen and genistein may explain, in part at least, the synergistic antiproliferative and cytotoxic actions of the two compounds. The synergism of tamoxifen and genistein may be of interest in the clinical treatment of breast carcinoma.

Antineoplastic Agents, Hormonal↗