[Expression and clinical significance of LRFN4 in colorectal cancer tissue].

Objective: To investigate the expression and clinical significance of LRFN4 in colorectal cancer. Methods: A total of 210 cases of colorectal cancer tissues and 228 cases of corresponding surgical margin tissues were collected. Immunohistochemistry was employed to evaluate the expression of LRFN4 in colorectal cancer.The correlation between LRFN4 expression and clinicopathological features of colorectal cancer as well as patient outcome were analyzed. Results: The positive rate of LRFN4 in colorectal cancer and in non-cancer was 55.24%(116/210), and 37.28% (85/228) , respectively.The expression of LRFN4 in colorectal cancer tissues was higher than that in non-cancer tissues(χ(2)=14.196, P<0.001). High expression of LRFN4 was significantly correlated with tumor location(χ(2)=4.133,P=0.042), T staging(χ(2)=6.494,P=0.039), N staging(χ(2)=11.715,P=0.008), TNM staging(χ(2)=13.398,P=0.004), CEA (χ(2)=6.017, P=0.049), but without gender, age, degree of differentiation, M staging(P>0.05).The Kaplan-Meier survival curves indicated that high LRFN4 expression was associated with good survival (P<0.05). In addition, Cox proportional hazards model showed that the high expression of LRFN4(HR=0.585, P=0.018)was an independent risk factor for prognosis in patients with colorectal cancer. Conclusions: The expression of LRFN4 is up-regulated in colorectal cancer, which is significantly correlated with the clinicopathological features and prognosis. High expression of LRFN4 reduced the risk of death in patients with colorectal cancer.

Isolation of a homocysteine gamma-lyase-producing bacterium and study of its enzyme production conditions.

AIM: To investigate the possibility of finding a new homocysteine (Hcy) gamma-lyase with the desired properties for Hcy measurement in bacteria. METHODS AND RESULTS: Through a process of enrichment, the Hcy gamma-lyase-producing bacterium strain N2-1 was isolated from soil. Based upon its morphological, physiological, and biochemical characteristics, as well as its 16S rDNA sequence and phylogenetic tree analysis, this isolate belongs to the genus Serratia. The effects of pH, aeration, inducers, carbon (C) and nitrogen (N) sources on enzyme production were studied. Methionine, yeast extract, and glucose were selected as the optimal inducer, C and N sources, respectively. Maximum production of Hcy gamma-lyase was obtained when the isolate was cultured at 30 degrees C at pH 6.5 for about 36 h in the optimum medium. Results also showed that this Hcy gamma-lyase has relatively high specificity towards Hcy. CONCLUSIONS: Because of its high specificity for Hcy, this bacterial Hcy gamma-lyase has the potential application in Hcy determination. SIGNIFICANCE AND IMPACT OF THE STUDY: In addition to isolating a bacterium that produces Hcy gamma-lyase suitable for Hcy determination, this study also indicates that the bacterium could be a source for production of Hcy gamma-lyase for clinical applications.

A nanogold-quenched fluorescence duplex probe for homogeneous DNA detection based on strand displacement.

A nanogold-quenched fluorescence duplex probe has been developed for lighting up homogenous hybridization assays. This novel probe is constructed from two strands of different lengths, and labeled by nanogold and a fluorophore at the long-strand 5'-end and the short-strand 3'-end, respectively. The two tags are in close contact, resulting in complete quenching of the probe fluorescence. If perfectly complemented to the nanogold-labeled strand, a long target oligonucleotide would displace the short fluorophore-labeled strand, and as a result, restore the fluorescence. By using nanogold in the probe, an extremely high quenching efficiency (99.1%) and removal of free fluorophore-labeled strand is achieved. The signal-to-noise ratio and the detection limit (50 pmol L(-1)) of homogenous assays are therefore improved significantly, in comparison with similar probes using organic acceptors. Moreover, the probe has a great inhibition effect on hybridization to a mismatched oligonucleotide. This effect provides the assay with a high specificity, and particularly the assay has great potential in applications for discriminating variations in sequences. The assay sensitivity could be markedly enhanced by using fluorescent materials in the signal strand that are brighter and not quenched by nucleobases.

Comparison of continuous and split-course radiotherapy for nasopharyngeal carcinoma--an analysis of 1446 cases with squamous cell carcinoma grade 3.

PURPOSE: An analysis of 1446 cases with squamous cell nasopharyngeal carcinoma Grade 3 was made for the comparison of treatment results of continuous (CG) and split-course (SG) radiotherapy regimens. METHODS AND MATERIALS: The patients were given their first definitive radiotherapy at our department from July 1977 to December 1980, 1093 cases by continuous treatment regimen, and 353 cases by split-course regimen. The interval of the split was 10-45 days, mean 28.6 days. Trials were nonrandomized, but the treatment conditions for both groups were the same. RESULTS: The 5-year survival rate was 33.6% for CG, and 26.9% for SG. For Stage III and IV patients, the 5-year survival rate was 31% (290/933) for CG, and 21.5% (36/107) and 18.8% (17/90) for those with a split of 21-30 and 31-45 days, respectively (both p < 0.05); the 5-year local control rate was 27.4% (256/933) for CG, and 15.5% (26/167) (p < 0.01), and 15.5% (14/90) (p < 0.05) for those with a split of 21-30 and 31-45 days, respectively. The metastatic rate in 5-years was 21.59% vs. 27.48% for CG to SG (p < 0.01), but not different statistically for any subgroup. No relation was confirmed between local control rate and radiation dose. CONCLUSION: According to the data obtained in this series, we believe that the treatment results of CG were superior to those of SG, especially for Stage III and IV patients, and those with a split of 21 days or more.