Biomedical subjects

X Z Liang

Publications and source records attributed to X Z Liang.

4 recordsLinked to original sources

PubMed2001

Adenoma of the posterior urethra: 131 case report.

AIM: A case-report on adenoma of the posterior urethra. METHODS: In 131 cases of adenoma of the posterior urethra, aged 17-79 (mean: 36.4) years, a detailed medical history was taken and urinalysis, urethroscopy, and prostatic specific antigen (PSA) immunohistochemical staining were performed. They were then treated with transurethral resection (TUR) or transurethral electric coagulation (TUEC). RESULTS: Hemospermia occurred in 51% of the cases, hematuria in 38%, blood overflow from the urethral orifice in 6%, and dysuria in 5%. The position of the tumor was at or around the verumontanum. The appearance of the tumor was similar to those of a papilla, a villus, a dactyl or polyp, or simply an engorgement. The tumor contained glandular alveoli and adeno-epithelial cells. PSA immunohistochemistry was positive in the cytoplasm and nucleus of the adeno-epithelial cell. One hundred and tweenty-nine cases were cured after TUR or TUEC, while 2 patients recurred and were operated again. CONCLUSION: Adenoma of the posterior urethra is a common cause of hemospermia and hematuria in young men. Urethroscopic examination and biopsy are the principal diagnostic measures. TUR or TUEC are believed to be the treatment of choice with a short-term recurrence rate of around 1. 5%.

Adenoma↗

PubMed1998

Monitoring oxygen partial pressure in tissue using microdialysis sampling and membrane coated oxygen sensors.

The use of microdialysis sampling coupled to oxygen sensors for monitoring oxygen tension in the tissue of animals was examined. The response time of the microdialysis sampling system was not different than oxygen sensors implanted directly in the tissue. The microdialysis system could be calibrated in vivo using the no-net-flux calibration method while directly implanted oxygen sensors had to rely on in vitro calibration. No difference was found in the oxygen tensions determined in vivo between microdialysis sampling and direct sensor implantations.

Animals↗

PubMed1995

Dual-electrode amperometric detection for the determination of SR4233 and its metabolites with microbore liquid chromatography.

3-Amino-1,2,4-benzotriazine-2,4-di-N-oxide (SR4233) is a promising new antineoplastic agent based on reductive activation. SR4233 and its major metabolites (SR4317 and SR4330) are all easily reduced at a carbon electrode. Reductive amperometric detection can therefore provide high selectivity and low detection limits with chromatographic analysis and is an ideal approach to detection of SR4233 in microdialysis samples. However, in order to use amperometric detection in the reductive mode, sample deoxygenation is necessary. This is typically done by purging the sample with either argon or nitrogen prior to injection. This approach is not feasible for microdialysis samples because only 5-10 microliters is usually available. In this report, a microbore liquid chromatographic method with dual-electrode amperometric detection is described for the determination of SR4233 and its metabolites without predeoxygenation. A dual-electrode amperometric detector was used in the series configuration with an upstream potential of -450 mV to reduce SR4233 and its metabolites to a common product and a downstream potential of +400 mV to oxidize this product. Oxygen is only electroactive at the upstream electrode because of its irreversible behavior. This method is compatible with the small sample volumes provided by microdialysis sampling. Linear calibration graphs were obtained up to 55 microM for SR4233, and 140 microM for both SR4317 and SR4330. The detection limits were 70 nM for SR4233, and 50 nM for SR4317 and SR4330. The average intra-day variation over 5 days was 1.8% (SR4233), 1.4% (SR4330), and 1.8% (SR4317), whereas the inter-day variation over 5 days was 14.1% (SR4233), 8.6% (SR4317), and 2.6% (SR4330).

Animals↗

PubMed1994

Wallifoliol, a taxol congener with a novel carbon skeleton, from Himalayan Taxus wallichiana.

A new taxoid, wallifoliol [3], has been isolated, along with five known taxoids (taxol, cephalomannine, 10-deacetylbaccatin III, brevifoliol, 2-acetoxy brevifoliol = taxchinin A) from extracts of the needles of Himalayan Taxus wallichiana. The structure of wallifoliol has been assigned primarily from nmr studies. Wallifoliol [3] is assigned a structure in which rings A and B of the taxane system have undergone putative rearrangements producing a novel skeleton. Wallifoliol is the first diterpene to be found in nature with this particular 5/6/6/6/4 ring system.

India↗