Biomedical subjects

Yue Chen

Publications and source records attributed to Yue Chen.

At least 73 records · Page 4Linked to original sources

PubMed2005

The association between allergy and diabetes in the Canadian population: implications for the Th1-Th2 hypothesis.

T-lymphocytes may preferentially differentiate towards a Th1 subtype, which is thought to be involved in the autoimmune aspects of diabetes, or a Th2 subtype, which is thought to mediate allergic disease. The activation of one subtype is thought to inhibit the other. To determine if diabetes is less common among those with allergic disease, consistent with the postulated TH1/Th2 paradigm, we used data from the 2000-2001 Canadian Community Health Survey of those at least 12 years of age from 125,159 households. Diabetes requiring insulin was reported in 1% whether or not allergies were reported. The crude odds ratio between diabetes and allergies for the entire population was 1.06 (95% confidence interval (CI): 0.90, 1.24). Adjusted for household size, number of bedrooms, immigrant status, income adequacy, educational level, smoking status, alcohol drinking status, regular exercise, and age, there was a positive association between allergy and diabetes with an odds ratio of 1.25 (95% CI: 1.06, 1.49). These results do not provide evidence for the existence of the Th1/Th2 paradigm as a determinant of disease patterns in the general population.

Adolescent↗

PubMed2005

Occurrence and clinical predictors of operative delivery for the vertex second twin after normal vaginal delivery of the first twin.

OBJECTIVE: This study was undertaken to estimate occurrence and explore clinical predictors of abdominal and vaginal operative delivery in vertex second twin after normal vaginal delivery of the first twin. METHODS: Data from a historical cohort study that was based on a twin registry in the United States (1995-1997) were used. RESULTS: Among 42,417 vertex second twins following normal vaginal delivery of the first twins, rates of abdominal and vaginal operative delivery were 6.3% and 8.3%, respectively. Cord prolapse, fetal distress, maternal complications, abnormal labor, and birth weight 25% larger than first twin were the most important predicators for operative deliveries. Fetal distress and cord prolapse had a stronger effect on abdominal than vaginal operative delivery. CONCLUSION: In general population, abdominal and vaginal operative delivery rates were 6.3% and 8.3%, respectively, in vertex second twin after normal vaginal delivery of the first twin. The most important predictors for operative delivery are cord prolapse and fetal distress.

Adult↗

PubMed2005

Neonatal death and morbidity in vertex-nonvertex second twins according to mode of delivery and birth weight.

OBJECTIVE: The purpose of this study was to assess the risk of neonatal death and morbidity in vertex-nonvertex second twins according to the mode of delivery and birth weight. STUDY DESIGN: Data from a retrospective cohort study that was based on all twin births in the United States (1995-1997) were used. RESULTS: A total of 15,185 vertex-nonvertex second twins were classified into 3 groups: (1) both twins were delivered by cesarean delivery (37.7%), (2) both twins were delivered vaginally (46.8%), and (3) the second twin was delivered by cesarean delivery after vaginal delivery of the first twin (15.5%). The risk of asphyxia-related neonatal deaths and morbidity was increased in the group in which both twins were delivered vaginally and the group in which both twins were delivered by cesarean delivery. The increase in neonatal death in the group in which both twins were delivered vaginally was stronger in the birth weight of < 1500 g. In contrast, in the group in which both twins were delivered vaginally and the group in which the second twin was delivered by cesarean delivery after the first twin was delivered vaginally, the increase in neonatal morbidity was greater in the group in which the birth weight was 1500 to 4000 g. CONCLUSION: The risk of neonatal death and morbidity in second-born twins is higher in the group in which both twins were delivered vaginally and the group in which the second twin was delivered by cesarean delivery after the first twin was delivered vaginally compared with the group in which both twins were delivered by cesarean delivery.

Adult↗

PubMed2005

Effects of subcutaneous administration of daidzein on blastocyst implantation in rats.

The study was conducted to investigate the effects of phytoestrogen daidzein on blastocyst implantation in rats. Following successful mating, female rats were given daidzein by subcutaneous administration at the dose of 0 (vehicle control, n=15), 50 mg/kg body weight (n=15) and 150 mg/kg body weight (n=15) daily on day 1-7 of pregnancy and were sacrificed on day 8 of gestation. The results revealed that high-dose treatment (150 mg/kg body weight) significantly diminished the rate of blastocyst implantation and serum levels of gonadotropin-releasing hormone (GnRH), progesterone, and gonadotropins (FSH and LH), meanwhile the serum level of beta endorphin increased significantly. These effects were not observed in the low-dose treatment group (50 mg/kg body weight). The results of this study suggested that the anti-implantation effects of daidzein are probably caused by the interference of the hypothalamus-pituitary-gonadal axis which is involved in the implantation process.

Animals↗

PubMed2005

The effect of coarse ambient particulate matter on first, second, and overall hospital admissions for respiratory disease among the elderly.

The objective of this article is to examine differences in the effect of ambient particulate matter on first, second, and overall hospital admissions for respiratory disease among the elderly. We studied 8989 adults 65 yr of age or older living in the greater Vancouver area who were admitted to hospital for any acute respiratory disease (ICD-9 codes 460-519) between June 1, 1995, and March 31, 1999. Time-series analysis was used to evaluate the association between respiratory admissions and daily measures of particulate matter (PM10, PM2.5, and PM10 - 2.5) in urban air, after adjustment for gaseous copollutants (CO, O3, NO2, and SO2) and meteorological variables. Repeated admissions for respiratory disease were common among the elderly. Approximately 30% of the subjects were readmitted to hospital after the first admission; 9% had more than 2 admissions for respiratory disease during the 4-yr study period. PM10 - 2.5 was significantly associated with the second and overall admissions for respiratory disease, but not with the first admission. The adjusted relative risks for an increment of 4.2 microg/m(3) in -day average PM10 - 2.5 concentrations were 1.03 (95% confidence interval: 0.98-1.09) for the first admission, 1.22 (1.10-1.36) for the second admission, and 1.06 (1.02, 1.11) for overall admissions. There was no significant association between PM2.5 and hospital admissions for respiratory disease among the elderly. Our data suggest that (1) people with a history of respiratory admissions are at a higher risk of respiratory disease in relation to particulate air pollution in urban areas, (2) analyses based on overall rather than repeated hospital admissions lead to lower estimates of the risk of respiratory disease associated with particulate air pollution, and (3) PM10 - 2.5 has a larger effect on respiratory admissions than PM2.5.

Aged↗

PubMed2005

Construction of an alpha toxin gene knockout mutant of Clostridium perfringens type A by use of a mobile group II intron.

In developing Clostridium perfringens as a safe vaccine vector, the alpha toxin gene (plc) in the bacterial chromosome must be permanently inactivated. Disrupting genes in C. perfringens by traditional mutagenesis methods is very difficult. Therefore, we developed a new strategy using group II intron-based Target-Tron technology to inactivate the plc gene in C. perfringens ATCC 3624. Western blot analysis showed no production of alpha toxin protein in the culture supernatant of the plc mutant. Advantages of this technology, such as site specificity, relatively high frequency of insertion, and introduction of no antibiotic resistance genes into the chromosome, could facilitate construction of other C. perfringens mutants.

Clostridium perfringens↗

PubMed2005

Increased risk of depression in COPD patients with higher education and income.

This study examined potential modifying effects of income and education on the relationship between chronic obstructive pulmonary disease (COPD) and depression. The analysis was based on 44,963 Canadians aged 35 years or more who participated in the Canadian National Population Health Survey in 1996-1997. Logistic regression analysis was used to examine the association between prevalence of depression and COPD according to sex, income adequacy or educational level. We used a bootstrap procedure to take sampling weights and design effects into account. People with COPD had twice the prevalence of depression compared to those without COPD. The association tended to be stronger in well-educated men [adjusted odds ratio (OR) = 3.02, 95% confidence interval (CI) = 1.04, 8.75] and women (OR = 2.60, 95% CI = 1.55, 4.38) than those less educated (men: OR= 1.19, 95% CI = 0.47, 3.05; women: OR = 1.93, 95% CI = 0.96, 3.87). An increased prevalence of depression associated with COPD was also found in women with higher household income (adjusted odds ratio = 4.57, 95% CI = 2.27, 9.19) than those with lower income. However, this pattern was not found in men. In conclusion, COPD patients with higher education are more likely to be depressed. The modifying effect of income may vary by gender. Possible reasons for these findings are explored.

Adult↗

PubMed2005

Endothelin-1 receptor antagonist BQ123 prevents pulmonary artery hypertension induced by low ambient temperature in broilers.

Evidence has indicated that endothelin-1 is related to the pathogenesis of hypertension. To characterize the role of endothelin-1 (ET-1) in the development of pulmonary hypertension syndrome in broilers, the blockade effect of ETA receptor (ET(A)) antagonist, BQ123, on blood pressure in experimental models of pulmonary hypertension was examined. Birds were locally anesthetized and instrumented with venous catheters for pulmonary arterial pressure (PAP) and right ventricular pressure (RVP), followed by packed cell volume (PCV) and Ascites heart index (AHI) measured, after exposed to low ambient temperature for 7 or 14 d. In treated groups, BQ123 (0.4 or 2.0 microg each time, 2 times a day), administered in abdominal cavities for 7 or 14 d during birds kept in low ambient temperature, prevented both PAP and RVP increasing, especially the high dose BQ123 lowered PAP and RVP to normotensive levels as that in control under normal temperature, whereas significant increases (p<0.05) were found in the two parameters of broilers in both untreated and saline treated group under low ambient temperature compared with those of birds in control. Furthermore, there was also a reduction in low ambient temperature-induced right ventricular hypertrophy in the groups administered BQ123. The preventive effect of BQ123 suggests that ET-1 is associated with the development of broilers' pulmonary hypertension, which leads to the development of ascites, and BQ123 can prevent the occurrence of pulmonary hypertension.

Age Factors↗

PubMed2005

Sex specificity of asthma associated with objectively measured body mass index and waist circumference: the Humboldt study.

STUDY OBJECTIVE: To investigate the possibility of sex specificity for the association of obesity and asthma using objective measures of body mass index (BMI) and waist circumference (WC). DESIGN: Cross-sectional study of adults (n = 2,057) living in Humboldt, SK, Canada in 2003. SETTING: A rural community. MEASUREMENTS: Ever-asthma was defined as lifetime physician-diagnosed asthma, and recent asthma was defined as asthma diagnosed by a physician during the past 12 months. BMI and WC were objectively measured. RESULTS: Among the participants, 5.6% of men and 10.0% of women reported having ever-asthma, and 2.7% and 6.0% had recent asthma, respectively. Higher levels of both BMI and WC were significantly associated with asthma in women but not in men. The adjusted odds ratios for women with a BMI of at least 30.0 kg/m2 relative to women with a BMI of < 25.0 kg/m2 were 2.06 (95% confidence interval [CI], 1.42 to 4.05) for ever-asthma and 3.47 (95% CI, 1.64 to 7.32) for recent asthma. CONCLUSIONS: Our study demonstrated that the increased risk of asthma associated with obesity was only significant in women but not in men even when BMI was objectively measured, and this association was robust to the anthropometric measures.

Adolescent↗

PubMed2005

Coarse particulate matter and hospitalization for respiratory infections in children younger than 15 years in Toronto: a case-crossover analysis.

OBJECTIVES: The purpose of this study was to examine the association between ambient air pollution and hospitalization for respiratory infections among children who were younger than 15 years in Toronto during a 4-year period (1998-2001). METHODS: Exposures averaged during periods that varied from 1 to 7 days were used to assess the effects of air pollutants, including thoracic particulate matter (PM10), fine (PM2.5) and coarse (PM10-2.5) particulate matter, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3), on hospitalization for respiratory infections. A case-crossover design was used to calculate odds ratios for the hospitalization adjusted for daily weather conditions with an incremented exposure corresponding to the interquartile range in air pollution exposures. RESULTS: When particulate matter and gaseous pollutants were mutually taken into account, the effect remained pronounced for PM10-2.5 in both boys and girls. The adjusted odds ratio for 6-day average exposure to PM10-2.5 with an increment of 6.5 microg/m3 was 1.15 (95% confidence interval: 1.02-1.30) for boys and 1.18 (95% confidence interval: 1.01-1.36) for girls. The effect also remained for PM10 in boys and for NO2 in girls. PM2.5, CO, SO2, and O3 showed no significant effects on hospitalization for respiratory infection in both genders when other pollutants were taken into consideration. CONCLUSION: Our study suggested a detrimental effect of relatively low levels of ambient particulate matter and gaseous pollutants, especially coarse particulate matter and NO2, on hospitalization for respiratory infections in children.

Adolescent↗

PubMed2005

Androgen regulation of satellite cell function.

Androgen treatment can enhance the size and strength of muscle. However, the mechanisms of androgen action in skeletal muscle are poorly understood. This review discusses potential mechanisms by which androgens regulate satellite cell activation and function. Studies have demonstrated that androgen administration increases satellite cell numbers in animals and humans in a dose-dependent manner. Moreover, androgens increase androgen receptor levels in satellite cells. In vitro, the results are contradictory as to whether androgens regulate satellite cell proliferation or differentiation. IGF-I is one major target of androgen action in satellite cells. In addition, the possibility of non-genomic actions of androgens on satellite cells is discussed. In summary, this review focuses on exploring potential mechanisms through which androgens regulate satellite cells, by analyzing developments from research in this area.

Aging↗

PubMed2005

[In vitro effect on the differentiation and maturation of monocyte-derived dendritic cells by mannan-binding lectin].

AIM: To explore the effect of mannan-binding lectin (MBL) on the differentiation and maturation of human peripheral blood monocyte-derived dendritic cells (MoDCs). METHODS: After MoDCs was stimulated with human natural MBL, MoDC's morphology was observed under inverted microscope and the expressions of CD1a, CD83, CD40, CD80, CD86 and HLA-DR on MoDCs were analyzed by FACS. The ability of MoDCs to stimulate the proliferation of allogenic T cells was detected by (3)H-TdR incorporation. The ability of MoDCs to up-take antigens was evaluated by zymosan granule phagocytosis test. The levels of IL-12 and TNF-alpha in the culture supernatant of MoDCs were determined by ELISA. RESULTS: The expressions of CD1a, CD83, CD40, CD80, CD86 and HLA-DR on the MoDCs were up-regulated by MBL. The ability of MoDCs to up-take zymosan granules decreased and the proliferation of native T cells induced by MoDCs was enhanced. MBL stimulated the production of IL-12 by MoDCs, but had no such effect on TNF-alpha secretion. CONCLUSION: MBL can induce differentiation and maturation of DCs in vitro, suggesting that MBL possibly participate in the adaptive immune response through modulation of functions of DCs.

Cell Differentiation↗

PubMed2005

[Expression of pulmonary surfactant-associated protein D and its significance in human fetal lung].

OBJECTIVE: To observe the expression of pulmonary surfactant-associated protein D (SP-D) during human fetal lung development. METHODS: Human fetal lung tissues from 11- to 36-week-old fetuses were assayed for lung maturity with HE staining and SP-D expression by means of immunohistochemistry. RESULTS: SP-D expression was located in the bronchial epithelium and alveolar epithelial type II cells(AEC II) of the lung tissues since the 12th week, and gradually increased during the canalicular to saccular stages with fetal development, at the point of which SP-D-positivity began a shift from the proximal bronchial epithelium to AEC II , and evidently located in the alveoli from the advanced stage of lung development till postnatal stage. CONCLUSIONS: SP-D expression gradually intensifies with the maturation of the fetal lungs, and SP-D-positive cells begin to be detected in the bronchial epithelium and finally in AEC II.

Adult↗

PubMed2005

[Effect of camera control devices of Cerec 2 on the fit of CAD/CAM all-ceramic copyings of posterior tooth].

OBJECTIVE: To investigate the effect of camera control devices of Cerec 2 on the fit of CAD/CAM all-ceramic copyings of posterior tooth. METHODS: 24 all-ceramic copyings were made by Cerec 2 with camera control devices and that without camera control devices. Copyings were embed and sectioned, then SEM and image analyzer was used to measure the space between the copyings and dies at the marginal opening, the axial wall, and the occlusal adaptation at the measurement locations. RESULTS: The marginal fit at buccal space of copyings with camera control devices group was smaller than that without camera control devices group (P < 0.05). The internal fit of of copyings had statistically significant difference at mesio-axial, disto-axial, bucco-axial, bucco-occlusal, linguo-occlusal and disto-occlusal space between camera control device group and without camera control devices group (P < 0.05). There was no statistical difference on the marginal fit and internal fit of copyings between Vita MK II and porous alumina oxide (P < 0.05). CONCLUSION: The Cerec 2 with camera control devices reduced effectively the inaccuracy of inner space of copyings which contributed from the technical errors of the operator, and provided well-proportioned space for adhesive. Both the fit of copyings made of Vita MK II and porous alumina oxide satisfied the clinical demand.

Aluminum Oxide↗

PubMed2005

[The relationship between TNF-alpha and the injury of renal tubular cells caused by anoxia/reoxygenation].

AIM: To investigate the relationship between TNF-alpha and renal tubular cell injury caused by anoxia/reoxygenation. METHODS: Human renal proximal tubular cell line HK-2 was used as model. Anoxia/reoxygenation were produced by covering/de-covering the cell culture with liquid paraffin wax. The level of TNF-alpha and the activity of lactate dehydrogenase(LDH) in the culture medium was determined by radioimmunoassay(RIA) and biochemical methods, respectively. Trypan blue exclusion was used to measure cell viability. RESULTS: Anoxia/reoxygenation could increase TNF-alpha level and LDH activity, but decrease viability of HK-2 cells. TNF-alpha level was positively correlated with LDH activity (r=0.89, P<0.05) and negatively with the cell viability (r=-0.91, P<0.05). CONCLUSION: TNF-alpha induced by anoxia/reoxygenation may participate in the process of renal tubular cell injury.

Cell Hypoxia↗

PubMed2005

[Role of interleukin-1 receptor antagonist in protecting kidney from injury induced by asphyxia in neonatal rats].

OBJECTIVE: To observe the role of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) in protecting kidney from injury induced by asphyxia in neonatal rats. METHODS: Neonatal rats were used as experimental animals. The changes in intrarenal inflammatory response and renal injury were examined in the control group (n=13), and 2, 24 and 48 hours after asphyxia followed by normal saline treatment in those treated with rhIL-1ra. RESULTS: In normal saline group, the white blood cell count, the blood interleukin-1 (IL-1), IL-8, IL-6, nitric oxide (NO), endothelin (ET-1) levels, and the renal coefficient (LRC), the scores of injured tubules of the left kidney were significantly increased at 2 hours (n=10), 24 hours (n=11), and 48 hours (n=10, P<0.05 or P<0.01). Compared with the normal saline group, the levels of the above parameters, except IL-6, were significantly decreased in rhIL-1ra treatment group at the same time points (P<0.05 or P<0.01). Serum IL-6 at 24 hours and 48 hours was also decreased in rhIL-1ra treatment group significantly (P<0.05 or P<0.01). CONCLUSION: The results suggest that rhIL-1ra may protect renal injury after asphyxia via inhibiting intrarenal inflammatory response.

Animals↗

PubMed2005

[Construction of standard recombinant plasmids for 7 common mannan-binding lectin gene haplotypes].

OBJECTIVE: To construct the standard recombinant plasmids for 7 common haplotypes of mannan-binding lectin (MBL) gene. METHODS: The DNA samples with known haplotypes and genotypes of MBL gene were used as the templates for amplifying the fragments of MBL gene haplotypes including the promoter region and exon 1 with sequence-specific primer-polymerase chain reaction (SSP-PCR) method. The amplified fragments were cloned into T vector and the bases located at codon 52 and codon 57 of exon 1 in MBL gene were mutated respectively by site-directed mutagenesis. All the 7 recombinant plasmids were identified by PCR and direct sequence analysis. RESULTS: From the DNA samples with known haplotypes and genotypes of MBL gene, the standard plasmids of haplotypes HYPA, LXPA, LYQA, LYPA and LYPB of MBL gene were constructed by SSP-PCR and molecular cloning technique. From the recombinant plasmids of HYPA and LYQA, the standard plasmids of haplotypes HYPD and LYQC of MBL gene were constructed by site-directed mutagenesis, respectively. CONCLUSION: The constructed standard plasmids of haplotypes HYPA, LXPA, LYQA, LYPA, LYPB, HYPD and LYQC of MBL gene provide standard controls for detecting the SNPs, haplotypes and genotypes of MBL gene with such genotyping methods us SSP-PCR and real-time PCR.

Base Sequence↗

PubMed2005

[Role of complement C3 in delayed-type hypersensitivity].

OBJECTIVE: To explore the role of complement C3 in delayed-type hypersensitivity (DTH). METHODS: After inducing DTH reaction in the footpads of C3 knockout C3(-/-) and wild-type (C3(+/+) ) mice with ovalbumin (OVA), the thickness of the footpad was measured and HE and immunohistochemical staining preformed to identify the number and types of the infiltrating mononuclear cells in the footpad tissues. T lymphocytes were separated from the spleens of the mice and incubated in 96-well plates with serial dilutions of OVA or mitogens in the presence of mitomycin C-treated macrophages, and the proliferation of the T cells was assessed by (3)H-TdR incorporation assay. RESULTS: The footpad thickness of DTH-C3(-/-) mice was significantly smaller than that of DTH-C3(+/+) mice. The number of the infiltrating mononuclear cells in the footpad tissue of C3(-/-) mice was obviously decreased in comparison with that of C3(+/+) mice, and the cells were characterized mainly as CD4(+) T lymphocytes. No significant difference in the proliferation of mitogen-stimulated splenic T cells was noted between C3(-/-) and C3(+/+) mice, but after stimulation with the specific antigen OVA, significant reduction in the proliferation of splenic T cells from C3(-/-) mice was observed as compared with the T cell proliferation in C3(+/+) mice. CONCLUSION: C3 defect results in impaired DTH responses in mice, which indicates the important role of C3 in DTH reaction.

Animals↗