Biomedical subjects

N W Yang

Publications and source records attributed to N W Yang.

3 recordsLinked to original sources

PubMed2001

CAS agar diffusion assay for the measurement of siderophores in biological fluids.

We developed a simple and universal method, by modifying the universal CAS (Chrome azurol S) assay, measuring siderophores in various biological fluids. We named the assay as CAS agar diffusion (CASAD) assay. CAS plate devoid of nutrients was prepared by using Bacto-agar (1.5%, w/v) as a matrix. Holes with 5-mm-diameter were punched on the CAS agar plate. Each hole was added by 35 microl of the test fluids containing Desferal that was twofold serially diluted. After incubating at 37 degrees C or room temperature for 4-8 h, the size of orange haloes formed around the holes was measured. The size of orange haloes correlated well with the concentration of Desferal in all the biological fluids tested in this study. CASAD assay showed consistent results in wide pH range from 5 to 9. Addition of iron to the test fluids containing Desferal decreased the size of orange haloes in a dose-dependent manner, which suggests that the CASAD assay detects only iron non-bound siderophore. These results suggest that CASAD assay would serve as a simple, stable, and highly reproducible test for screening and quantitative siderophore analysis in biological fluids.

Amniotic Fluid↗

PubMed2001

Cloning and characterization of a novel gene (C17orf25) from the deletion region on chromosome 17p13.3 in hepatocelular carcinoma.

Using a combination of hybridization of PAC to a cDNA library and RACE technique, we isolated a novel cDNA, designated as C17orf25 (Chromosome 17 open reading frame 25, previously named it HC71A), from the deletion region on chromosome 17p13.3. The cDNA encodes a protein of 313 amino acids with a calculated molecular mass of 34.8 kDa. C17orf25 is divided into 10 exons and 9 introns, spanning 23 kb of genomic DNA. Northern blot analysis showed that the mRNA expression of C17orf25 was decreased in hepatocellular carcinoma samples as compared to adjacent noncancerous liver tissues from the same patients. The transfection of C17orf25 into the hepatocellular carcinoma cell SMMC7721 and overexpression could inhibit the cell growth. The above results indicate that C17orf25 is a novel human gene, and the cloning and preliminary characterization of C17orf25 is a prerequisite for further functional analysis of this novel gene in human hepatocellular carcinoma.

Amino Acid Sequence↗

PubMed2000

Novel intracochlear electrode positioner: effects on electrode position.

Spiral ganglion cells, located in the cochlear modiolus, are widely thought to be the neural elements stimulated by cochlear implants (CIs). Positioning CI electrodes adjacent to the modiolus may allow delivery of more focused, discrete fields of electrical stimulation, reducing both current requirements and the channel interaction associated with simultaneous stimulation. In order to provide greater consistency in positioning CI electrodes against the modiolus, Advanced Bionics Corporation has designed a silicone intracochlear positioner that is inserted alongside the electrode. Placed against the outer wall of the scala tympani, it directs the electrode array toward the modiolus. Five fresh-frozen temporal bones were studied to validate enhanced electrode placement. Electrode position was documented with image-enhanced digital fluoroscopy, and the distance to the modiolus was measured with computer-assisted morphometrics. The electrode positioner was highly effective in positioning the electrodes closer to the modiolus (p < .001).

Adult↗