Biomedical subjects

C Yoon

Publications and source records attributed to C Yoon.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Aliasing artifacts in MR imaging.

Aliasing artifacts occur in the phase encoding direction when the dimensions of the imaged object exceeds the field of view. Signal generated from outside the field of view appears as a superimposed object at the opposite edge of the image. Increasing the field of view, changing the gradient axes relative to the patient, or use of surface coils can reduce aliasing and are parameters which are controlled by the radiologist/technologist. The manufacturer may provide software packages which exploit two additional strategies, either limiting the volume of the patient from which the MR signal is acquired as in Inner Volume Imaging or display of resolution unless the number of phase encoding steps is increased at a cost of increased acquisition time. The radiologist may in some clinical situations choose to tolerate aliasing in favor of improved resolution in the area of interest and decreased acquisition time.

Fourier Analysis↗

PubMedDate not supplied

Drug testing at the 10th Asian Games and 24th Seoul Olympic Games.

Drug testing (doping test) procedures in the 1986 10th Asian Olympic Games and 1988 24th Seoul Olympic Games are reported. The International Olympic Committee Medical Commission (IOC-MC) conducted its first doping tests at the 1968 Olympics in Grenoble. With the guidance of the International Olympic Committee (IOC), the Olympic Council of Asia (OCA) introduced doping tests at the 1986 10th Asian Olympic Games in Seoul, Korea, September 21st to October 5th, 1986. 585 samples were tested at the Doping Control Center, Korea Advanced Institute of Science and Technology (DCC/KAIST), for stimulants, narcotics, anabolic steroids, and beta-blockers by gas chromatography/mass spectrometry, high pressure liquid chromatography, and fluorescence polarization immunoassay. These tests covered about 100 different drugs and another 400 as metabolites in addition to pharmacologically related substances. For the Seoul Olympic Games from September 17 to October 2, 1988, the IOC-MC with the DCC/KAIST conducted doping tests on 1601 samples for stimulants, narcotics, beta-blockers, diuretics, and anabolic steroids using GC, HPLC, GC/MSD, GC/MS, LC/MS, and TDx.

Doping in Sports↗

PubMedDate not supplied

Efficacy of new platinum analog DPPE in an orthotopic nude mouse model of human colon cancer.

A surgical orthotopic implantation (S.O.I.) model of the human colon cancer cell line Co-3 in nude mice was treated with two doses of the new platinum analogs {Pt(cis-dach) (DPPE).2NO3} and {Pt(trans-dach)(DPPE).2NO3}. The analogs were evaluated for antimetastatic efficacy in comparison to two doses of cisplatinum. Unlike the untreated control group, there were no mesenteric lymph node metastases in the groups treated with the high or low doses of both forms of new DPPE platinum analogs as well as cisplatinum-treated group. However, much more body-weight loss occurred in the cisplatinum-treated group than the DPPE-treated groups. The results obtained with SOI animal model of colon cancer demonstrated both cis- and trans-forms of DPPE had as strong an inhibitory effect on metastasis as that of cisplatinum, but with much less toxicity. Thus the new platinum analogs appears to have promising clinical potential.

Animals↗

PubMedDate not supplied

The measurement of glucose consumption in histoculture to determine effects of doxorubicin and cisplatinum on human gastric carcinoma.

We have developed a chemosensitivity assay of human tumors growing on collagen-sponge-gel-supported histoculture. This assay is thus termed the Histoculture Drug Response Assay (HDRA). In the HDRA, the end points of [3H]thymidine incorporation measured by histological autoradiography and tetrazolium dye reduction were initially used and found to have good in vitro-in vivo correlations, including that determined in clinical trials. We have now developed glucose consumption as an endpoint in histoculture. We have monitored glucose consumption for 11 weeks with histocultured stomach cancer tissue that was obtained from a patient with stomach cancer metastatic to the lymph node. The histocultured lymph node specimens were treated with various concentrations of doxorubicin and cisplatinum. The glucose-consumption rate decreased with greater concentrations of both drugs. The results correlated with the thymidine labeling index. From these results, we conclude that the glucose-consumption-rate endpoint in histocultured cancer tissue is non-destructive, unlike the [3H]thymidine and tetrazolium dye end points, allowing serial determinations over extended periods in culture. Thus, the glucose consumption end point may enhance the development of optimal treatment doses and schedules. We also conclude that long-term histoculture drug response studies of metastatic stomach cancer are possible.

Cisplatin↗