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H L Cheng

Publications and source records attributed to H L Cheng.

68 records · Page 4Linked to original sources
PubMed1986

An efficient and general method for sequencing immunoglobulin mRNAs.

By using two oligonucleotide primers, one complementary to a short DNA segment in the first constant region exon and second complementary to a short segment in the variable region, we have developed a highly efficient method for sequencing immunoglobulin mRNAs. Using the first primer full length immunoglobulin-specific cDNA was synthesized and separated on a denaturing acrylamide/urea gel. The desired band was isolated from the gel and sequenced by Maxam/Gilbert method. Using the sequence generated, a second oligonucleotide primer complementary to a short segment in the variable region was synthesized and similarly used to complete the remaining sequence of the variable region, the signal peptide and the 5'-untranslated region. We have used this method to determine the complete nucleotide sequence of heavy and light chain mRNAs from two anti-idiotypic hybridomas. The method is generally applicable to sequencing immunoglobulin mRNAs from both myelomas and hybridomas especially in instances involving the expression of more than one heavy or light chain mRNAs as well as instances involving additional transcripts from aberrantly rearranged immunoglobulin genes.

Amino Acid Sequence↗
PubMed1986

A self-splicing RNA excises an intron lariat.

We have investigated the in vitro self-splicing of a class II mitochondrial intron. A model pre-mRNA containing intron 5 gamma of the oxi 3 gene of yeast mitochondrial DNA undergoes an efficient intramolecular rearrangement reaction in vitro. This reaction proceeds under conditions distinct from those optimal for self-splicing of class I introns, such as the Tetrahymena nuclear rRNA intron. Intron 5 gamma is excised as a nonlinear RNA indistinguishable from the in vivo excised intron product by gel electrophoresis and primer extension analysis. Studies of the in vitro excised intron product strongly indicate that it is a branched RNA with a circular component joined by a linkage other than a 3'-5' phosphodiester. Two other products, the spliced exons and the broken form of the lariat, were also characterized. These results show that the class II intron products are similar to those of nuclear pre-mRNA splicing.

DNA, Mitochondrial↗
PubMedDate not supplied

Laparoscopic wedge resection of benign gastric tumor.

BACKGROUND/AIMS: In the past 2 years, 9 patients diagnosed as benign gastric tumor pre-operatively underwent laparoscopic wedge resection of stomach at National Taiwan University Hospital. Among them, 6 were females and 3 were males. METHODOLOGY: Histopathologically, 7 of 9 cases were of gastrointestinal stromal tumor (GIST). The clinical characteristics of this group were retrospectively reviewed and compared with another 12 cases of benign gastric tumor receiving open wedge resection in the same period. RESULTS: There were no differences in sex, age, and pre-operative diagnosis in these two groups. It took a significantly longer operation time in the laparoscopic group than it did in the open group (205.71 vs. 97.5 min, p<0.05). However, the patients of the laparoscopic group started post-operative oral intake earlier (4.0 vs. 5.58 days, p<0.05), had shorter hospital stays (6.67 vs. 10.77 days, p<0.05), and lower analgesic usage rate (55% vs. 100%). There were no differences in operative complication rates. CONCLUSIONS: Laparoscopic resection of benign-gastric tumor is recommended as a minimally invasive procedure.

Adult↗
PubMedDate not supplied

Expression of vascular endothelial growth factor in primary superficial bladder cancer.

BACKGROUND: Angiogenesis is of vital importance during the development and progression of solid tumors. This study was performed to test the clinical significance of vascular endothelial growth factor (VEGF) expression in primary superficial bladder cancer. MATERIALS AND METHOD: A cohort of 185 cases of pTa/pT1 transitional cell bladder cancer and six cases of normal urothelium were studied by immunohistochemistry. Expression of VEGF was correlated with biological indicators of bladder cancer and examined for their prognostic value. RESULTS: Variable amounts of VEGF were detected in 35 cases (18.9%), with 17.9% and 20.3% in pTa and pT1 tumors respectively. There was a positive association of VEGF expression with histological grading (p = 0.03). Otherwise, no apparent correlation was observed with remaining biopathological indicators (p > 0.1, respectively). Risk factors in predicting tumor recurrence were multiple tumors at diagnosis and lamina propria invasion (p < 0.05, respectively). Patients with multiple tumors also had a lower survival rate than those with a solitary tumor (p = 0.0008). However, expression of VEGF was not correlated with risk of tumor recurrence or patient survival (p > 0.1). CONCLUSIONS: Expression of VEGF is one of the characteristics of tumor dedifferentiation and may play a role in the development of a subset of superficial bladder cancer. Evaluation of VEGF expression dose not provide independent prognostic information for patients with superficial bladder cancer.

Adult↗
PubMedDate not supplied

The clinical value of p21WAF1/CIP1 expression in superficial bladder cancer.

The clinical value of p21WAF1/CIP1 in superficial bladder cancer remains controversial. To address the question, we examined the expression patterns of p21 and p53 gene products and compared for their significance in a total of 89 cases of superficial (pTa/pT1) bladder cancer. Over-expression of p21 was detected in 32 of 89 (36%) tumors. But, the expression status did not correlate with biological indicators or clinical outcome (p > 0.1, respectively). Factors predicting clinical outcome were multiplicity for tumor recurrence (p = 0.0002) or patient survival (p = 0.03), and the histological grading for disease progression (p = 0.02) or patient survival (p = 0.05). Taking into account the p53 status, a trend approaching better prognosis for p53+p21+ tumors was observed compared with that of p53+p21- bladder cancer (p = 0.08). Our data indicate that evaluation of p21 status does not provide better prognostic information compared with conventional biological indicators of superficial bladder cancer. Maintenance of p21 appears to abrogate the deleterious effects of p53 alterations in the tumorigenesis of human bladder.

Adult↗
PubMedDate not supplied

Expression of nm23-H1 in transitional cell carcinoma of the upper urinary tract.

Transitional cell carcinoma of the upper urinary tract is an uncommon neoplasm. Relatively little information is available regarding the clinical relevance of molecular markers. This study was performed to examine the importance of nm23-H1 gene expression (NM23-H1) in this type of tumors. Immunohistochemical expression of NM23-H1 was analyzed in 90 cases of upper urinary tract cancer, and was compared for its prognostic significance with conventional biological indicators. High expression of NM23-H1 was found in 7 cases (8%), intermediate expression in 32 cases (36%), and low expression in 51 cases (57%). Reduced NM23-H1 (defined as intermediate or low level of expression) was associated with a higher histological grading (p=0.002), invasive tumor growth (p=0. 002), or an increased proliferating cell nuclear antigen labeling index (p=0.004). NM23-H1 tended to inversely relate to later recurrence or long-term survival (p=0.06), but, only tumor staging was found to be significant in predicting clinical outcome (p=0.002). nm23-H1 appears to function as a tumor suppressor for upper urinary tract cancer, however, evaluation of NM23-H1 provides limited prognostic information.

Adult↗
PubMedDate not supplied

Role of beta 2-microglobulinuria and microalbuminuria in pediatric febrile urinary tract infection.

Urinary beta-2-microglobulin (beta 2M) and microalbumin concentrations were analyzed in 61 pediatric patients with febrile urinary tract infection (UTI). The results were compared with those of technetium-99m-labeled dimercaptosuccinic acid (99mTc-DMSA) single photon emission computed tomography (SPECT) imaging. Noninvasive evaluations were made to localize the site of the UTI. Increased urinary beta 2M/Creatinine (Cr) or microalbumin/Cr quotients were not associated with renal inflammation, as defined by a positive renal scan. Increased urinary microalbumin/Cr is associated with UTI in febrile patients regardless of the level of infection (scan status), and may be an informative indicator of UTI. When microalbumin/Cr was > or = 0.03, its sensitivity and specificity to predict UTI in febrile patients, regardless of the site of the infection, were 95.65% and 51.79%, respectively, and its positive predictive value was 62.0%. On the other hand, urinary beta 2M/Cr (> or = 0.13) demonstrates a statistically significant correlation with the presentation of a high grade of vesicoureteral reflux (p = 0.02). We suggest that a prompt renal imaging study is warranted when the urinary beta 2M/Cr ratio is high (> or = 0.13).

Albuminuria↗
PubMedDate not supplied

Significance of urinary tissue polypeptide specific antigen (TPS) determination in patients with urothelial carcinoma.

Tissue polypeptide specific antigen (TPS) is the M3 epitope of the tissue polypeptide antigen, and a specific epithelial proliferation marker. To examine the benefit of urine TPS (UTPS) measurement in the diagnosis and classification of biological properties of transitional cell carcinoma (TCC), a radioimmunoassay of U-TPS was measured in patients with active TCC (n = 56), at tumor-free status (n = 36), with inflammatory urological disease (n = 44), and age-sex adjusted normal subjects (n = 75). Both neoplastic and inflammatory urological diseases had an increase in U-TPS levels (U/gm creatinine) compared to normal individuals (p = 0.0005), while it normalized in tumor-free condition (p = 0.007). For patients with active TCC, a strong positive association was observed between U-TPS values and both histological grading (p = 0.05) and positive cytology (p = 0.05). U-TPS levels were significantly higher in the presence of nodal or systemic metastasis (p = 0.008 by ANOVA test). Measurement of U-TPS appeared to be an indicator of poor outcome for patients with bladder cancer (p = 0.05 by t test) for a mean follow-up of 26 months. The results indicate that determination of U-TPS can be a supplement in assessing the biological properties of TCC, and may be helpful in identifying patients who need meticulous peri-operative staging survey.

Adult↗
PubMedDate not supplied

Significance of urinary epidermal growth factor and its receptor expression in human bladder cancer.

UNLABELLED: The expression of epidermal growth factor receptor (EGFR) has been suggested to play an important role in the progression of bladder cancer through paracrine stimulation by epidermal growth factor in the urine. However, there is no information regarding the expression of EGFR and urinary ligand measurement in corresponding tumors in patients with bladder cancer. MATERIALS AND METHODS: Paired analysis of urinary levels of epidermal growth factor (U-EGF) and the expression of EGFR was performed on 48 cases of bladder cancer. U-EGF test and EGFR status were correlated with clinicopathologic factors of bladder cancer, and compared for their prognostic value with a mean follow-up of 39.7 months. RESULTS: U-EGF was inversely correlated with the intensity of EGFR expression (p = 0.04); while no substantial relationship was observed with other conventional prognostic indicators (p > 0.1, respectively). Multivariate analysis revealed that factors correlated with the risk of recurrence were EGFR status (p = 0.03) and histological grading (p = 0.05). An important indicator associated with poor patient survival was size of tumor at diagnosis (p = 0.03). DISCUSSION: Although measurement of U-EGF levels did not have any independent prognostic value, our data support the importance of urine EGF/urothelial EGFR interaction in the biological behavior of bladder cancer.

Adult↗
PubMedDate not supplied

Prognostic significance of proliferating cell nuclear antigen expression in transitional cell carcinoma of the upper urinary tract.

BACKGROUND: Haphazard cell proliferation is a fundamental biologic defect in cancer. Thus, assessment of the growth fraction provides a valuable index of biological property for human neoplasm. Proliferating cell nuclear antigen (PCNA) expression has been used to estimate the growth fraction of human cancer, and its prognostic value. Information in transitional cell carcinoma (TCC) of the upper urinary tract, however, is very few. MATERIALS AND METHODS: A total of 73 patients with TCC of the upper urinary tract was collected between July 1988 and December 1995 for this study. The labeling index of PCNA immunostaining was correlated with clinicopathologic factors and compared for its prognostic value with a median follow-up of 54 months. RESULTS: The PCNA index was positively associated with histological grading, tumor stage and patient prognosis (P = 0.00, respectively). Multivariate analysis demonstrated that significant factors in relation to patient survival were tumor stage (P = 0.01), followed by PCNA index (P = 0.04) and gender of patients (P = 0.04). Multiple comparison revealed that PCNA index set at 0.30 had prognostic value in terms of patient survival (P = 0.00), and the risk of metachronous bladder recurrence (P = 0.02). CONCLUSION: Our data suggested that assessment of PCNA index may be used as an adjuvant prognostic factor for patients with TCC of the upper urinary tract.

Adult↗