Biomedical subjects

Ling-Ling Hsieh

Publications and source records attributed to Ling-Ling Hsieh.

30 records · Page 2Linked to original sources

PubMed2004

Evaluation of meiotic spindles in thawed oocytes after vitrification using polarized light microscopy.

OBJECTIVE: To investigate the efficacy of the PolScope on imaging the spindle morphology in oocytes at the metaphase II stage before vitrification and after thawing. DESIGN: In vitro study. SETTING: University infertility clinic and academic research laboratory. INTERVENTION(S): Oocytes at the metaphase II stage that were obtained from superovulating mice were vitrified and then thawed. MAIN OUTCOME MEASURE(S): Morphological features of the spindle in oocytes were evaluated by both the PolScope and immunofluorescent staining. RESULT(S): Using the PolScope, the morphological features of the spindle of intact thawed oocytes were undetected by 3 hours of thawing in only 25% of cases. Most of the spindle images were recognized during the first hour of observation. Additionally, the statistical analysis of agreement of spindle morphology by both the PolScope and fluorescent staining showed a weighted Kappa value of 0.70, indicating good agreement. Oocytes with good spindle morphology verified by the PolScope before vitrification had a higher survival rate of intact oocytes after thawing compared with those with poor or undetected spindle images. CONCLUSION(S): The morphological features of the spindle in oocytes evaluated by the PolScope before freezing and after thawing are significantly correlated with those assessed by immunofluorescent staining after fixation. With the assistance of the PolScope, thawed oocytes with good spindle morphology can be verified and selected for further manipulation without fixation and staining.

Animals↗

PubMed2004

Degradation of MTBE in dilute aqueous solution by gamma radiolysis.

The radiolytic degradation of methyl tert-butyl ether (MTBE) in air-equilibrated dilute solution was investigated. Complete degradation of MTBE can be achieved within 5 min of irradiation at 59.7 Gy/min. The observed first-order degradation rate constant, called dose constant, increased from 0.04 to 0.56 Gy(-1) as the concentration of MTBE decreased from 92500 to 19 microg/L. Tert-butyl formate, tert-butyl alcohol, acetone and methyl acetate were found to be the primary intermediates of the degradation reaction with yields of 47%, 11%, 6.4% and 9.1%, respectively. The degradation of MTBE or its intermediates was also found to depend on the concentrations of benzene and cupric ion. The study shows that the removal of MTBE can be significantly decreased with increasing concentration of benzene. Little affects were observed with the presence of cupric ions, while the degradation of TBF was apparently reduced. These results indicate that gamma radiolysis can be a potentially effective treatment for the removal of MTBE in contaminated water systems.

Carcinogens↗

PubMed2004

Humoral response to p53 is associated with conserved domains II and IV mutations in human colorectal cancer: a case-control study in Taiwan.

To explore the relationship between mutations of the p53 gene, p53 protein accumulation in tumor tissues and the presence of anti-p53 antibodies (Ab) in sera, a matched case-control study with 63 colorectal cancer patients positive for p53-Ab was carried out. These control patients were matched for age, gender, as well as tumor site and stage with 63 colorectal cancer patients positive for p53-Ab. The study was designed to analyze their p53 gene mutations in exons 4-9 by the single strand conformation polymorphism (SSCP) followed by direct sequencing, as well as measuring p53 protein accumulation by immunohistochemistry. A significantly higher frequency of p53 mutations in exon 4-9 and positive immunohistochemical staining of p53 protein was observed in tumors from p53-Ab positive patients (55.56 and 84.13%, respectively) than in tumors from p53-Ab negative patients (22.22 and 60.32%, respectively). Using a conditional logistic regression model, the humoral response to p53 was found to be associated with p53 gene mutation (OR = 3.34; 95% CI, 1.31-8.54, p=0.012) and p53 protein accumulation (OR = 3.80; 95% CI, 1.02-14.14, p=0.047). Further analysis showed that the frequency of p53 mutations located in the conserved domains II (codons 112-141) and IV (codons 234-258) was significantly higher in p53-Ab positive patients than in p53-Ab negative patients (50.00% (16/32) vs. 8.33% (1/12), p=0.015, Fisher's exact test). Thus, our study demonstrated that the generation of p53 antibodies was usually correlated with the p53 protein accumulation and p53 gene mutation, especially mutations located in conserved domains II and IV.

Adenocarcinoma↗

PubMed2003

XRCC1, CYP2E1 and ALDH2 genetic polymorphisms and sister chromatid exchange frequency alterations amongst vinyl chloride monomer-exposed polyvinyl chloride workers.

Vinyl chloride monomer (VCM) is a known human carcinogen, which may be metabolized by cytochrome P450 2E1 (CYP2E1), aldehyde dehydrogenase 2 (ALDH2), and glutathione S-transferase T1 (GSTT1). A DNA-repair gene, X-ray repair cross-complementing group 1 ( XRCC1, exon 10), may also be implicated in the process of VCM-related carcinogenesis. Thus, VCM-exposed workers with inherited susceptible metabolic and DNA-repair genotypes may experience an increased risk of genotoxiciy. This study was designed to investigate whether metabolic and DNA-repair genotypes affected sister chromatid exchange (SCE) frequency in occupationally VCM-exposed workers from polyvinyl chloride (PVC) manufacturing plants. Study subjects comprised 61 male workers having experienced VCM exposure, and 29 male controls. Questionnaires were administered to obtain detailed histories of cigarette-smoking habits, alcohol consumption behavior, and occupation. The frequency of SCE in peripheral lymphocytes was determined using a standardized method, and genotypes of CYP2E1, ALDH2, GSTT1 and XRCC1 were identified by the polymerase chain reaction (PCR) procedure. Our results demonstrated that smoking, age and VCM exposure and XRCC1 ( P=0.03), CYP2E1 ( P=0.04), and ALDH2 ( P=0.08) were significantly associated with an increased SCE frequency. Further analysis of gene combinations, including CYP2E1, ALDH2 and XRCC1, revealed an increased trend for these genotypes to influence SCE frequencies for the low VCM-exposure group ( P<0.01), but not so for the high VCM-exposure group ( P=0.29) or for controls ( P=0.49). These results suggest that workers with susceptible metabolic and DNA-repair genotypes, may experience an increased risk of DNA damage elicited by VCM exposure.

Adult↗

PubMed2003

Profiling of gene expression associated with hepatolithiasis by complementary DNA expression array.

By use of cDNA expression array method, we compared the expression profiles of genes in hepatolithiasis tissues with those of paired normal tissues. Expression of 1176 cancer related genes that include 33 tumor suppressor genes, 100 proto-oncogenes and 37 DNA damage repair genes were examined in this study. We found that expression of tumor suppressor genes and proto-oncogenes was systemically activated in hepatholithiasis tissues, suggesting that expression of genes controlling cell growth becomes unstable in liver lobe of hepatolithiasis. In contrast, expression of DNA damage repair genes were not activated but rather remained unchanged in hepatholithiasis tissues, suggesting that repair process is not strongly activated but rather impaired in hepatholithiasis tissues.

Calculi↗

PubMed2003

The XRCC1 399Gln polymorphism and the frequency of p53 mutations in Taiwanese oral squamous cell carcinomas.

DNA repair gene polymorphisms have been implicated as susceptibility factors in cancer development. It is possible that DNA repair polymorphisms may also influence the risk of gene mutation. The 399Gln polymorphism in the DNA repair gene XRCC1 has been indicated to have a contributive role in DNA adduct formation, sister chromatid exchange, and an increased risk of cancer development. Two hundred thirty-seven male oral squamous cell carcinomas (OSCCs) were included in a study to investigate the role of the XRCC1 194Trp, 280His, and 399Gln polymorphisms on p53 gene mutation. PCR-single-strand conformation polymorphism and DNA sequencing were used to analyze the conserved regions of the p53 gene (exons 5-9). The XRCC1 genotype was determined by PCR-RFLP. Nineteen (8.02%) of the 237 OSCCs had a Gln/Gln genotype. One hundred six (43.88%) of the 237 OSCCs showed p53 gene mutations at exons 5-9. The OSCC patients with a Gln/Gln genotype exhibited a significantly higher frequency of p53 mutation than those with an Arg/Gln and an Arg/Arg genotype. After adjustment for age, cigarette smoking, areca quid chewing, and alcohol drinking, the Gln/Gln genotype still showed an independent association with the frequency of p53 mutation (odd ratio, 4.50; 95% confidence interval, 1.52-13.36). The findings support the hypothesis that XRCC1 Arg399Gln amino acid change may alter the phenotype of the XRCC1 protein, resulting in a DNA repair deficiency. This study also suggests an important role for the XRCC1 399Gln polymorphism in p53 gene mutation in Taiwanese OSCCs.

Adult↗

PubMed2003

Risk factors for colorectal cancer in Taiwan: a hospital-based case-control study.

BACKGROUND AND PURPOSE: There have been few studies of the risk factors associated with colorectal cancer in Taiwan, a country of low incidence of the disease. This study investigated whether dietary and lifestyle factors correlate with colorectal cancer risks in Taiwan. METHODS: A total of 352 patients with colon cancer and 375 patients with rectal cancer histologically confirmed between 1995 to 1999 at a medical center in northern Taiwan were included in the study. They were age- and gender-matched with 736 healthy controls who were recruited from the health examination clinic at the same hospital. Dietary intake and lifestyle variables were ascertained using a standardized questionnaire. Unconditional multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: The risk of colon cancer and of rectal cancer was inversely associated with vegetable/fruit consumption in both men and women. The adjusted ORs based on the highest versus the lowest tertile consumption were 0.36 (95% CI, 0.21 to 0.61) and 0.44 (95% CI, 0.27 to 0.72) for men, respectively. The corresponding ORs for women were 0.32 (95% CI, 0.19 to 0.56) and 0.39 (95% CI, 0.23 to 0.69), respectively. However, the highest versus the lowest tertile meat consumption was associated with significantly elevated risk in both men and women for both colon cancer (ORs, 1.85 and 2.29, respectively) and rectal cancer (ORs, 2.32 and 2.42, respectively). Risk also increased with less exercise, low or moderate coffee consumption, cigarette smoking and alcohol intake, and decreased with the frequency of fish/shrimp consumption among men. CONCLUSIONS: Consistent with the findings of previous studies in Western populations, this study found that vegetable and fruit consumption, less meat consumption, and exercise were associated with a reduced incidence of colorectal cancer in Taiwanese.

Case-Control Studies↗

PubMed2003

Lack of correlation of betel nut chewing, tobacco smoking, and alcohol consumption with telomerase activity and the severity of oral cancer.

BACKGROUND: Oral cancer is one of the most frequent cancers. A strong association has been found between oral cancer incidence and the use of betel nut, alcohol, and tobacco. Telomerase activity (TA) has also been shown to play a role in carcinogenesis. We therefore surveyed the consumption habits of betel nut chewing, alcohol drinking, and tobacco smoking in oral cancer patients and evaluated the association of these habits with TA level and clinical stage. METHODS: In total, 154 oral cancer patients were recruited. TA was measured in paired (grossly normal and cancerous) tissues using a polymerase chain reaction-based enzyme immunoassay. Associations of these factors with clinical stage and TA level were analyzed using the Pearson chi-square test. RESULTS: In these patients, 86.4%, 61.0%, and 83.3% used betel nut, alcohol, and tobacco, respectively. For all tissue assayed, 80.5% of cancerous and 3.2% of grossly normal mucosae were positive for TA. However, neither clinical stage nor TA level in cancerous tissues had a statistical association with the use of individual substances (betel nut, alcohol, and tobacco) or their combined use. CONCLUSION: Even though the habitual uses of these substances have been previously reported to be associated with oral cancer incidence, we found a lack of correlation with TA level or with disease severity in our study. These results imply that these consumption habits might only be associated with the early stages of oral cancer development, while the later stages of cancer progression may be more associated with other external factors or dependent on host cellular factors, all of which require confirmation through further investigations.

Adult↗

PubMed2002

Allelic alterations at the STR markers in the buccal tissue cells of oral cancer patients and the oral epithelial cells of healthy betel quid-chewers: an evaluation of forensic applicability.

Although cancerous specimens are usually not used in forensic DNA typing, they might be forcibly employed under certain instances. On the other hand, though the oral epithelial samples have been applied to forensic identification, the great popularity of betel quid (BQ)-chewing in Taiwan, which is known to be a risk factor leading to an oral cancer, makes this application questionable. The DNA stability of nine short tandem repeat (STR) markers (the AmpFlSTR kit) was first investigated and then used to evaluate the forensic appropriateness of the oral samples of both healthy BQ-chewers and the archived clinical specimens from oral cancer patients. The analyses were performed on buccal samples from 100 BQ-chewers and 100 oral cancer patients, as well as their paired peripheral blood samples, and a group of 100 non-BQ-chewers were used for the control. In the group of 100 oral cancer patients, two types of DNA instability were found. They were major allelic imbalance, and allelic alterations including the expansion, the contraction and the un-classified type (i.e. can not be confirmed as the expansion or the contraction). The overall percentage of the cancerous subjects demonstrating DNA instability was 33% (five patients possessing both types of DNA instability). Both types of DNA instability showed a tendency of increasing with the severity of the pathological stage of oral cancer. Forty-four occurrences of major allelic imbalance were found from 21 cancer patients. The statistical result revealed that there was no significant difference in the allelic imbalanced occurrence among the nine STR loci. Allelic alterations were found in 17 patients, within which 12 individuals had the expansion, five had the contraction, and three were the un-classified type. Further, among these 17 patients, three were found to acquire multiple allelic alterations at multiple loci. In the group of 100 unrelated healthy BQ-chewers, two loci with major allelic imbalance were detected. However, the two imbalanced alleles were virtually half lost, and could still be recognized as heterozygous alleles. The statistical results of ANOVA, chi(2), and Scheffe tests indicated that the means of allelic imbalance at the nine STR loci of the oral cancerous group revealed a significant difference from those in the control group. Our results suggest that oral cancer tissues cannot be used as references for forensic purposes using the PCR-based STR systems, whereas the oral swabs from healthy BQ-chewers can be employed, but should be done with caution.

Adult↗

PubMed2002

The association between frequencies of mitomycin C-induced sister chromatid exchange and cancer risk in arseniasis.

In order to examine whether biomarkers of cytogenetic damage and susceptibility, such as spontaneous and mitomycin C-induced sister chromatid exchange (SCE) can predict cancer development, a nested case-control study was performed in a blackfoot endemic area with known high cancer risk. A cohort of 686 residents was recruited from three villages in the arseniasis area. Personal characteristics were collected and venous blood was drawn for lymphocyte culture and stored in a refrigerator. The vital status and cancer development was followed using the National Death Registry, Cancer Registry, and Blackfoot Disease Registry. The follow up period was from August 1991 to July 1997. During this 6-year-period, 55 residents developed various types of cancer. Blood culture samples from 23 of these subjects were unsuitable for spontaneous SCE experiments and 45 of these subjects were unsuitable for mitomycin C-induced SCE experiments due to improper storage. Finally, a total of 32 cancer cases had cytogenetic samples that could be analyzed. About 32 control subjects were selected from those who did not develop cancer in the study period and these subjects were matched to cases by sex, age, smoking habits, and residential area. The results showed that there was no significant difference in the frequencies of spontaneous and mitomycin C-induced SCE between the case and control groups. There was also no significant difference in the net difference of spontaneous and mitomycin C-induced SCE between the case and control groups. These results suggest that SCEs, either spontaneous or mitomycin C-induced, might not be good markers to predict cancer risk.

Arsenic↗

PubMed2002

A reverse transcription comparative real-time PCR method for quantitative detection of angiogenic growth factors in head and neck cancer patients.

OBJECTIVES: Head and neck cancer is one of the ten most frequent cancers in the world. The angiogenic growth factors VEGF, PDGF and bFGF play a role in cancer aggressiveness. We developed a sensitive method to quantify the gene expression of these factors in the tissues of head and neck cancer patients. DESIGN AND METHODS: All assays were performed using real-time RT-PCR, which yields a value (Ct) denoting the threshold cycle of PCR amplification at which product is first detected by fluorescence. The Ct is dependent on the quantity of the target molecule in the sample. To control for variation in RNA quantity and quality, we used 18S ribosome RNA as an internal control to calculate a relative Ct for the target molecules of interest, VEGF, PDGF and bFGF. A serially diluted positive control sample was analyzed by linear regression to determine the sensitivity and linearity of the assay. Paired normal and cancerous tissue samples from 115 head and neck cancer patients were assayed to ascertain the relative levels of the growth factors. RESULTS: The CVs of within-run and between-run assays for VEGF, PDGF and bFGF were all less than 3%. The correlation coefficient of the RNA concentrations and Ct values were 0.9987, 0.9977, and 0.9996 respectively for VEGF, PDGF and bFGF. The assay was sensitive to as little as 10(-3) ng of RNA. All three growth factors were significantly increased in tumor tissue as compared to normal tissue. VEGF, PDGF and bFGF levels were elevated in 71.3%, 58.2% and 54.0% of cancerous tissue samples, with average levels of over-expression of 35.1, 24.6 and 13. sixfold, respectively. CONCLUSION: This method provides sensitive, quantitative, high-throughput analysis for direct comparison of gene expression levels between samples, while adjusting for factors that may influence quantity determination. It should be applicable to molecules other than angiogenic growth factors, as well.

Endothelial Growth Factors↗

PubMed2002

Interaction of collagen-related genes and susceptibility to betel quid-induced oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a precancerous condition of the oral cavity. It is a collagen-related disorder induced by betel quid chewing, a habit that is common in Taiwan. However, the cumulative exposure to betel quids varies in OSF patients. It seems that there is individual susceptibility to betel quid-induced OSF. This study compared the association of OSF and polymorphisms of six collagen-related genes, collagen 1A1 and 1A2 (COL1A1 and COL1A2), collagenase-1 (COLase), transforming growth factor beta1 (TGF-beta1), lysyl oxidase (LYOXase), and cystatin C (CST3), between patients with low and high exposure to betel quids. A total of 166 patients with OSF from a medical center and 284 betel quid chewers who were free of OSF and oral cancer, from the same hospital and five townships, were recruited. PCR-based restriction fragment length polymorphism assays were used to determine the genotypes of the six collagen-related genes situated on different chromosomes. We found that the genotypes associated with the highest OSF risk for collagen 1A1, collagen 1A2, collagenase-1, transforming growth factor beta1, lysyl oxidase, and cystatin C were CC, AA, TT, CC, AA, and AA, respectively, for the low-exposure group, and TT, BB, AA, CC, GG, and AA, respectively, for the high-exposure group. A trend was noted for an increased risk of OSF with increasing number of high-risk alleles for those with both high and low exposures for betel quid. The cell selection mechanism of oral fibroblasts is proposed to explain the effect of the modification of cumulative betel quid exposure on the risk profiles of collagen-related genes. These results imply that susceptibility to OSF could involve multigenic mechanisms modified by the betel quid-exposure dose.

Adult↗