Biomedical subjects

I N Lee

Publications and source records attributed to I N Lee.

8 recordsLinked to original sources

PubMed2001

Deletion mapping of chromosome 16q24 in hepatocellular carcinoma in Taiwan and mutational analysis of the 17-beta-HSD gene localized to the region.

Human chromosome band 16q24 commonly undergoes loss of heterozygosity (LOH) in human hepatocellular carcinoma (HCC). To further localize the region of deletion on 16q24 and to evaluate the genetic role of 17-beta-HSD, which is near 16q24, in HCC, we examined the pattern of loss of heterozygosity in 88 HCC patients. DNAs from 88 pairs of HCCs and corresponding non-tumor parts were prepared. Loss of heterozygosity on chromosomes 16q24 was investigated by 11 sets of microsatellite markers. Mutation analysis of type II 17-beta-HSD was performed by automatic sequencing. LOH on 16q24 for at least 1 locus was found in 43 of the 88 tumor DNAs (49%). Three non-overlapping regions of frequent LOH were defined in these 43 tumors with partial deletions. The first region was between D16S516 loci and D16S507, encompassed by a 1-cM region, defined by the D16S504. The second region was defined by the 17HSDB2 locus between D16S505 and D16S422, encompassed approximately by a 1-cM region. The third region was between D16S520 and D16S413, defined by D16S3048, encompassed approximately by a 4-cM region. Homozygous deletions of any exons in 17HSDB2 gene were identified in 7 of 27 cases (26%). Automated sequencing analysis of 17HSDB2 failed to demonstrate mutations in any of these specimens. Our data suggest that the 17HSDB2 locus is a frequent target of deletion in HCC but the inactivation of 17HSDB2 may not involve sequence mutations. Furthermore, the presence of the other 2 frequent LOH regions suggest that the putative tumor suppressor genes at these locations might be involved in the development of HCC.

17-Hydroxysteroid Dehydrogenases↗

PubMed2001

A missing data treatment for data mining applications in medical information systems.

To apply user-friendly, easily operated and accessible tools to handle missing data resulting from an auto-stored medical information system, these tools are applied to satisfy general users from different disciplines (i.e. statistics and machine-learning), followed by medical information system development. This study attempts to develop a new logic separation inference method applied to a database with a format like most real-world medical records containing many missing data and miscellaneous variables. It is expected that this method should have better performance than currently accessible methods. The newly developed logic separation inference method shows a classification power of 0.997 (elimination method is 1), which is better than the simple replacing method (replaced by mode shows 0.974). Both inference methods (mode and mean) have superior classification power to the simple replacing method. The missing data treatment processes introduced in this study can be completed on a MS Excel spreadsheet without any complicated calculation; therefore, they can satisfy general users. This new missing data treatment method is only applied up to 60% of the missing data (missing at random). However, when there is large amount of data, it is expected that this method also can be applied to a database missing more than 60%.

Humans↗

PubMed1994

A mass spectrometric solution to the address problem of combinatorial libraries.

The molecular weights of femtomole quantities of small peptides attached to polystyrene beads have been determined with imaging time-of-flight secondary ion mass spectrometry. The analysis is made possible by the selective clipping of the bond linking the peptide to a bead with trifluoroacetic acid vapor before the secondary ion mass spectrometry assay. The approach can be applied to large numbers of 30- to 60-micrometer polystyrene beads for the direct characterization of massive combinatorial libraries.

Amino Acid Sequence↗

PubMed1988

Hemostatic suture for septoplasty: how we do it.

One of the disadvantages of the septoplasty procedure is patient discomfort, mainly from nasal packing, usually necessitating hospital stay. In an attempt to overcome some of this problem, a method was sought to replace the purpose of packing; namely hemostasis, prevention of hematoma and displacement of the retained cartilage. A continuous septal suturing technique was conceived some years ago by one of the authors (LV) and since then used extensively and perfected by both. Using this method in more than 800 cases (both septoplasties and septorhinoplasties) has proved to considerably reduce patient discomfort by eliminating nasal packs, and allowed the septoplasty procedure to be carried out in most cases on a day-surgery basis, also reducing the hospital stay of the septorhinoplasties. The final postoperative appearance of the septum also seems better than previously. We conclude that the use of the continuous hemostatic-stabilizing septal suturing technique is a useful modification of the standard procedure, with only minor increase in operating time.

Hemostasis, Surgical↗

PubMed1987

Additivity of detector responses of a portable direct-reading 10.2 eV photoionization detector and a flame ionization gas chromatograph for atmospheres of multicomponent organics: use of PID/FID ratios.

The H-Nu PI-101 with a photoionization detector (PID) of 10.2 eV and the Century OVA-128 equipped with a flame ionization detector (FID) were evaluated for the additivity of their responses to a defined mixture of dissimilar organic vapors at a 0 and 90% relative humidity (RH). The responses of both instruments were additive as long as the effect of RH was accounted for with the PID. The PI-101 was not as precise as the Century OVA-128 for 90% RH atmospheres. PID/FID ratios did not change in the presence of 90% RH as long as the effect of RH also was accounted for in the PID reading.

Chemistry Techniques, Analytical↗

PubMed1985

Outpatient management of T and A procedure in children.

Present financial constraints make outpatient (day) surgery--provided it is proven to be safe--an attractive option for patients and surgeons as well as hospitals. The author had noticed some reluctance among surgeons at previous meetings to consider doing children's T and A surgery in this manner. Based on more than 3,000 cases, over a four year period, the safety of the procedure is shown. It is hoped that the 0% re-admission rate for primary hemorrhage will encourage those who have not so far felt comfortable with this method.

Adenoidectomy↗

PubMed1976

A mode of selective action of thiadiazolyl urea herbicides.

1,1-Dimethyl-3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(I) was newly synthesized by the authors. (I) was found to have the strongest herbicidal activities among the thiadiazolylurea derivatives and selectivity of (I) was found between barley (tolerant)and wheat (susceptible) plants. Neither absorption by roots nor translocation from roots to shoots of 35S-labeled (I) in barley and wheat correlated with selectively between these species of plants. (I) was metabolized in both species of plants by N-demethylation to 1-methyl-3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(II), and further to non-phytotoxic 3-(5-tert-butyl-1,3,4-thiadiazol-2-yl)urea(III). The rates of the N-demethylating reactions from (I) to (II) and from (II) to (III) were much greater in barley shoots than in wheat shoots, especially in the second demethylation. It was concluded that the selective activity of (I) between barley and wheat plants was mainly due to the difference in rates of N-demethylation of (I). In addition, it was found that cotton plants, well known as tolerant to phenylurea herbicides, were remarkably susceptible to (I). It was indicated that different rates of the N-demethylating reaction between the phenyl and thiadiazolyl herbicides correlated with susceptibility to them.

Biotransformation↗

PubMedDate not supplied

Data mining techniques applied to medical information.

Knowledge discovery from the dramatically increased data of an auto-stored medical information system is still in its infancy. The purpose of this study is to use widely available and easily operated techniques that can satisfy general users in extracting specific knowledge to make the medical information system more functional. Data mining techniques, including data visualisation, correlation analysis, discriminant analysis, and neural networks supervised classification, were applied to heart disease databases. These techniques can help to identify high risk patients, define the most important factors (variables) in heart disease, and build a multivariate relationship model to show the relationship between any two variables in a way that such relationships are easy to view. Simple visualization techniques were utilised to construct this model, which corresponds with current medical knowledge. Two nonparametric (distribution assumption free) classification tools were employed to identify high risk heart disease patients. Both the neural networks supervised classification methods and the discriminant analysis method produced reliable classification rates for heart disease patients. However, neural networks yielded a higher percentage of correct classifications (averaging 89%) than discriminant analysis (79%). Data visualisation and correlation analysis resulted in similar conclusions regarding the most important factors in heart disease. These data mining tools provide simple and effective methods of extracting knowledge from general medical information. The treatment of missing data is also discussed.

Computer Graphics↗