Biomedical subjects

Li-Yu Tsai

Publications and source records attributed to Li-Yu Tsai.

28 records · Page 2Linked to original sources

PubMed2004

Lack of modulating influence of GSTM1 and GSTT1 polymorphisms on urinary biomonitoring markers in coke-oven workers.

BACKGROUND: Coke-oven workers (COWs) are occupationally exposed to high concentrations of polycyclic aromatic hydrocarbons (PAHs). Urinary 8-hydroxy-2-deoxyguanosine (8-OH-dG) and 1-hydroxypyrene (1-OHP) are biological markers of oxidative DNA damage and PAHs metabolism, respectively. In this study, we investigated whether polymorphisms of glutathione S-transferase (GSTM1 and GSTT1) can modulate the relationship between urinary 8-OH-dG and 1-OHP concentrations among the COWs. METHODS: This was a cross-sectional study. Between February and November of 2001, 53 topside-oven and 130 side-oven workers with the presence of GSTM1 and GSTT1 genotypes were investigated. RESULTS: Urinary 1-OHP and 8-OH-dG concentrations (mean +/- SD) in the topside-oven workers with the presence of GSTM1 were 107.2 +/- 107.9 and 15.3 +/- 9.7 ng/ml, respectively, which were not significantly different from those in the absence of GSTM1 (84.1 +/- 104.5 and 12.8 +/- 14.1 ng/ml). The similar insignificant results were also noted in the sideoven workers. For GSTT1 polymorphism, the results remained insignificant. In contrast, individual excretion of urinary 8-OH-dG and 1-OHP concentrations were still highly correlated (Spearman correlation coefficients: r = 0.43, P < 0.0001, n = 183). CONCLUSIONS: GST may not play a role in the regulation of metabolism of urinary biological markers in COWs.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2004

Effect of leukocyte depletion on endothelial cell activation and transendothelial migration of leukocytes during cardiopulmonary bypass.

BACKGROUND: Although leukocyte depletion from systemic circulation during cardiopulmonary bypass (CPB) has been studied, the effect of leukocyte depletion on the leukocyte-endothelial cascade remains poorly understood. So far, there has been no published work on the effects of leukocyte filters during cardiac operations from the viewpoint of endothelial activation and transendothelial neutrophil migration. METHODS: Thirty-two patients undergoing elective heart operations were randomly allocated to a leukocyte-depletion (LD) group or a control group. Blood samples were collected at seven time points: before sternotomy, at 30 minutes and at 60 minutes of CPB, at 5 minutes after coronary reperfusion, at the end of CPB, and at 2 hours and 24 hours after the cessation of CPB. The plasma concentrations of P-selectin, intercellular adhesion molecule-1 (ICAM-1), interleukin-8, and platelet-endothelial cell adhesion molecule-1 (PECAM-1) were measured using enzyme-linked immunosorbent assays. Plasma malondialdehyde (MDA) concentration was determined by measurement of thiobarbituric acid-reactive substances in plasma. In addition, blood samples collected at intervals before and after operation were used for arterial blood gases. RESULTS: Our studies show significant increases of plasma levels of P-selectin, ICAM-1, interleukin-8, PECAM-1, and MDA during and after CPB in the control group. Interestingly, a significant decrease of plasma levels of P-selectin, ICAM-1, interleukin-8, PECAM-1, and MDA, and better preservation of lung function could be found in the LD group compared with the control group. CONCLUSIONS: Our results demonstrate a rationale for using a leukocyte filter in patients undergoing cardiac surgery to attenuate the endothelial-mediated component of the CPB-induced inflammatory response by reducing endothelial activation and neutrophil transmigration.

Adult↗

PubMed2004

Aberrant expression and possible involvement of the leptin receptor in endometrial cancer.

OBJECTIVE: Leptin and its receptor are the key players in the regulation of energy balance and body weight control. However, their roles in gynecological malignancies are mostly unclear. In this study, we analyzed the expression and possible involvement of leptin and the leptin receptor in the pathogenesis of endometrial cancer. METHODS: Radioimmunoassay was performed to analyze the serum leptin levels in the endometrial cancer patients, while RT-PCR, immunoblotting, and immunohistochemistry techniques were applied to study the expression of leptin receptor in the endometrioid-type endometrial cancer tissues. Furthermore, BrdU labeling followed by immunofluorescent analysis was used to analyze the effect of leptin receptor overexpression on endometrial cancer cell proliferation. RESULTS: Serum leptin levels are elevated in endometrial cancer patients, but show no significant difference to those of normal controls when normalized by body mass index. On the other hand, lower expression levels of leptin receptor short form (Ob-Ra) were observed in most endometrial cancer tissues, especially in the poorly differentiated ones, and the forced expression of Ob-Ra in RL95-2 endometrial cancer cells prevented them from entering the S-phase. CONCLUSION: In summary, our data demonstrates for the first time that the leptin receptor is aberrantly expressed in endometrial cancer tissues and is possibly involved in the pathogenesis of endometrial cancer.

Cell Division↗

PubMed2004

Effects of traditional Chinese medicines on serum lipid profiles and homocysteine in the ovariectomized rats.

To investigate the effects of the traditional Chinese medicines, kuei-lu-erh-hsien-chiao and chia-wei-hsiao-yao-san, on the cardiovascular systems of mimic menopausal rats, five groups were formed: group 1 (the control group) was given a sham operation and received distilled water, while groups 2, 3, 4 and 5 were ovariectomized and received distilled water, kuei-lu-erh-hsien-chiao, chia-wei-hsiao-yao-san and 17-beta-estradiol, respectively, for4 months. Our results demonstrated that the mean differences of the estrogen levels in groups 3 or 5 were significantly higher than those of group 2. These data suggest that there might be some estrogen-like substances in kuei-lu-erh-hsien-chiao. However, the function of these estrogen-like substances was unknown. The mean differences of the triglyceride (TG) levels, high-density lipoprotein cholesterol (HDL-C) levels, low-density lipoprotein cholesterol (LDL-C) levels, and the ratios of TC/HDL-C and LDL-C/HDL-C in groups 1, 3, 4 and 5 were not significantly different from those in group 2. The mean differences of the total cholesterol (TC) levels in group 5 were significantly higher than those in group 2 (p < 0.05), but no obvious difference of the TC levels was found between groups 2 and 4. Nevertheless, the mean differences of the homocysteine (Hcy) levels in groups 4 and 5 were statistically lower than those of group 2. Therefore, administration of chia-wei-hsiao-yao-san declines the Hcy levels in OVX rats and does not affect the TC levels in these animals. In conclusion, our results indicate that chia-wei-hsiao-yao-san shows a more profound effect than 17-beta-estradiol in the prevention of atherosclerosis in these OVX rats.

Animals↗

PubMed2004

Differential expression of manganese containing superoxide dismutase in patients with breast cancer in Taiwan.

This study used Western blot analysis to measure the expression of superoxide dismutases (Mn-SOD and Cu/Zn-SOD) in breast cancer tissues from 57 patients. Mn-SOD expression in the breast cancer tissues averaged 1.5-fold higher than in the adjacent tumor-free tissues (p <0.05). There was no significant difference in Cu/Zn-SOD expression between neoplastic and tumor-free breast tissues. This study shows a significant increase of Mn-SOD expression in breast cancer tissues. The authors speculate that up-regulation of Mn-SOD expression induced by oxidative stress or local inflammation may contribute a selective growth advantage to tumor cells compared to their normal counterparts.

Blotting, Western↗

PubMed2004

Association of apolipoprotein E genotypes with serum lipid profiles in a healthy population of Taiwan.

Apolipoprotein E (apoE, protein; APOE, gene) plays a major role in lipoprotein metabolism and lipid transport. Many investigators have described associations between apoE genotypes, coronary artery disease (CAD), and other risk factors. The aim of this study was to investigate the association between apoE genotypes and serum lipid profiles in a healthy population of 220 volunteers at Kaohsiung in Taiwan. Other CAD risk factors such as serum levels of apolipoprotein A-I (apoA-I), apolipoprotein B, (apoB), homocysteine (Hcy), folate, and vitamin B12 were also measured. ApoE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In the study population, the frequency of apoE allele epsilon3 was greatest (85.2%); the frequency of epsilon2 was 8.4%; and that of epsilon4 was 6.4%. The serum apoA-1/apoB ratio showed significant difference among the 3 apoE genotype groups (p 0.0001); the apoA-1/apoB ratio was 1.9 +/- 0.1 (mean +/- SD) in the epsilon2 group, vs 1.4 +/- 0.04 and 1.5 +/- 0.12 in the epsilon3 and epsilon4 groups, respectively. No significant associations were found between APOE alleles and the serum levels of the various lipids or other CHD risk factors.

Apolipoproteins E↗

PubMed2003

Determination of thiobarbituric acid adduct of malondialdehyde using on-line microdialysis coupled with high-performance liquid chromatography.

An on-line analytical system for the continuous monitoring of malondialdehyde (MDA) was developed. This method involves the use of microdialysis perfusion, on-line derivatization and on-line HPLC analysis. This method gave a linear response for MDA concentrations and HPLC peak areas in the range from 0.051 microM to 2.43 microM. The intra-day (RSD = 1.6-10.5%) and inter-day (RSD = 1.1-9.3%) precisions were acceptable. The average in vitro probe recovery of MDA standard was 18.4 +/- 1.0%. The detection limit was 0.03 microM, corresponding to 0.6 pmol for an injection volume of 20 microl. This method was used for in vitro peroxidation investigations, which provided evidence for elevated MDA levels following the incubation of metal ions to a linoleic acid solution.

Chromatography, High Pressure Liquid↗

PubMed2003

Spectrophotometric determination of a thiobarbituric acid-reactive substance in human hair.

A simple and sensitive spectrophotometric method for the determination of a thiobarbituric acid-reactive substance (TBARS) in human hair has been developed. The proposed method is based on the formation of a red-colored product by the reaction of products of lipid peroxidation with thiobarbituric acid in an acidic medium. The absorbance of the resulting red product was measured at 534 nm. The linear dynamic range was between 1.0 and 20 micromol/L. The recoveries were 98.3-105.0%, and the relative standard deviations (RSD) were 0.32-1.24, respectively. TBARS in digested hair sample was stable for 3 days at room temperature. It was found that, using this method, the hair TBARS concentration in smokers (0.116 +/- 0.030 micromol/g, n = 30) was significantly higher than that in non-smokers (0.096 +/- 0.015 micromol/g, n = 30) (p < 0.05).

Butylated Hydroxytoluene↗

PubMed2003

Diagnostic value of urine deoxypyridinoline for detecting bone metastases in breast cancer patients.

Deoxypyridinoline (Dpd), a crosslink product of collagen molecules found in bone and excreted in urine during bone degradation, has been described as a marker of bone turnover in metastatic breast cancer. In this study, the urine deoxypyridinoline/creatinine (Dpd/Cre) ratio was determined by enzyme immunoassay in urine samples from 116 women with breast cancer. Bone metastases were confirmed by x-ray or CT scan, with follow-up > 6 mo. The urine Dpd/Cre ratio was significantly higher in patients with bone metastasis, compared to those without bone metastasis (p < 0.05). In patients with bone metastasis, ratios of urine Dpd/Cre were higher in those with multiple lesions, compared to those with a solitary lesion, and the values also reflected therapeutic response (p < 0.05). Serial monitoring of urine Dpd/Cre revealed that an elevation was correlated with disease progression. Patients with stable bone disease under effective therapy had significant diminution of the urine Dpd/Cre ratios, compared to those with progression of bone disease (p < 0.05). In conclusion, the urine Dpd/Cre ratio may be a useful marker for detecting bone metastases and evaluating their response to therapy.

Adult↗

PubMedDate not supplied

A study of glutathione status in the blood and tissues of patients with breast cancer.

Glutathione plays an important role in the antioxidant system that is required for the maintenance of the redox status of the cell, defence against free radicals and detoxification of toxic compounds. Reduced glutathione (redGSH) can be converted to oxidized glutathione (GSSG) during oxidative stress. The ratio of redGSH/total glutathione can be regarded as an index of the redox status and a useful indicator of disease risks. We conducted experiments by the capillary zone electrophoresis method to investigate the alterations of the glutathione status in the blood and tissue samples from patients with breast cancer. The results showed that the levels of redGSH, GSSG, total glutathione and the ratio of redGSH/total glutathione were significantly decreased in the blood of the patients with breast cancer compared to those of the control subjects. The levels of various forms of glutathione were lower and more pronounced in stage III. In contrast, the levels of redGSH, GSSG, total glutathione and the redGSH/total glutathione ratio in breast cancer tissues were significantly increased relative to those of the adjacent cancer-free tissues, especially in stage II. We suggest that the high redGSH levels are associated with the enhancement of cell proliferation and resistance to apoptosis in the cancer cells, and the loss of the large amount of erythrocyte redGSH may be due to increased detoxification capacities and defence against oxidative stress. We propose that redGSH should be regarded as an important biochemical parameter for detecting breast malignancy.

Adult↗