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Biomedical subjects

C K Liang

Publications and source records attributed to C K Liang.

6 recordsLinked to original sources
PubMed1999

Human telomerase reverse transcriptase (hTERT) gene expression in FNA samples from thyroid neoplasms.

BACKGROUND: Although fine-needle aspiration (FNA) is the most sensitive method for the detection of thyroid carcinoma, it cannot provide a definitive diagnosis of malignancy in 60% of the patients operated on for suspicious lesions. Recently, human telomerase reverse transcriptase (hTERT) has been found to be a diagnostic marker of malignancy. We therefore sought to determine whether hTERT gene expression could serve as an adjunct to FNA in the differential diagnosis of thyroid nodules. METHODS: Twenty-four FNA samples from thyroid nodules that were suspected of malignancy were collected. RNA was extracted, and hTERT gene expression was examined by RT-PCR. Cytologic and histologic examinations were also performed. RESULTS: Two of three follicular, three of three Hürthle cell, and eight of eight papillary thyroid carcinomas had corresponding FNA samples that were positive for hTERT. One of two Hürthle cell adenomas was hTERT positive. FNA samples from three follicular adenomas and five hyperplastic nodules were negative for hTERT. Positive and negative predictive values were 93% and 90%, respectively. CONCLUSIONS: The detection of hTERT gene expression in thyroid FNA samples holds promise as a diagnostic marker in the distinction of benign from malignant thyroid lesions. Its application could alter the surgical management of these patients.

Adenocarcinoma, Follicular↗
PubMed1999

Human telomerase reverse transcriptase (hTERT) gene expression in thyroid neoplasms.

Ten percent of fine-needle aspirations (FNAs) of the thyroid are deemed "indeterminate" or "suspicious" for malignancy by the cytopathologist, but most of these lesions are benign. Therefore, additional markers of malignancy may prove to be a useful adjunct. The catalytic component of telomerase, human telomerase reverse transcriptase (hTERT), has been found to be reactivated in immortalized cell lines. Reverse transcription-PCR of the hTERT gene revealed expression in 15 (79%) of 19 malignant thyroid neoplasms, including 6 of 6 follicular carcinomas and 9 of 13 papillary carcinomas. In contrast, hTERT gene expression was detected in only 5 (28%) of 18 benign thyroid nodules, including 2 of 7 follicular adenomas and 3 of 11 hyperplastic nodules. All five benign thyroids exhibiting hTERT gene expression had lymphocytic thyroiditis. No normal thyroids exhibited hTERT gene expression. Telomerase enzyme activity was examined in all 37 nodules and was found to correlate with hTERT gene expression in 35 (95%) nodules. The two cases in which telomerase activity and hTERT expression results were discrepant were in two papillary carcinomas that were telomerase activity negative and hTERT positive. Finally, we have demonstrated that hTERT gene expression can be measured in in vivo FNA samples. These results suggest that hTERT expression may be more accurate than telomerase activity in distinguishing benign from malignant and may be measured in FNA samples from suspicious thyroid lesions.

Biomarkers, Tumor↗
PubMed1995

Long-term exposure to fluoride in drinking water and sister chromatid exchange frequency in human blood lymphocytes.

The genetic toxicity of fluoride has been investigated extensively by various test systems. However, results obtained have been inconsistent. Fluoride has been reported to be non-genotoxic, genotoxic, and synergistic or antagonistic with certain mutagens. To date, there are no published human studies on the genotoxicity of fluoride. The purpose of this investigation was to determine genotoxic risks of long-term exposure to various concentrations of fluoride in drinking water in humans with normal or inadequate nutrition. Six groups of subjects with either normal or inadequate nutritional intakes were selected from areas of approximately 0.2, 1.0, or 4.8 ppm (10.5, 52.6, or 252.6 mumol/L) fluoride in water. The subjects had been continuous residents in the area for at least 35 years. Samples of drinking water, plasma, and urine were analyzed for fluoride content. Blood lymphocytes were examined to determine the frequency of sister chromatid exchange (SCE). Blood chemistry and electrolytes were also analyzed. The results showed that average daily fluoride intake as well as urine and plasma fluoride levels increased with increase in the fluoride content of the drinking water. The blood chemistry and electrolyte values were within the normal range for all populations, but several parameters were significantly different. While the numerical differences were small, the subjects with low fluoride in the water (0.11 and 0.23 ppm or 5.8 and 12.1 mumol/L) had significantly higher SCE frequencies than those with higher fluoride exposures.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Natural inhalation exposure to coal smoke and wood smoke induces lung cancer in mice and rats.

In an rural area with a high mortality rate of lung cancer in humans, mice and rats were placed in an environment in which they inhaled coal smoke and wood smoke in indoor air for 15 to 19 months. The incidences of lung cancer in mice in the control group, wood group, and coal group were 17.0% (29/171), 45.8% (81/177), and 89.5% (188/210), respectively: in rats the incidences were 0.9% (1/110), 0 (0/110), and 67.2% (84/125), respectively. In addition, the pollutants in the air were analyzed. The results indicate that coal smoke is a highly significant risk factor for lung cancer in humans in Xuan Wei County of Yun Nan Province in China.

Adenocarcinoma↗