Biomedical subjects

S-H Choi

Publications and source records attributed to S-H Choi.

4 recordsLinked to original sources

PubMed2006

The infrabony defect and its determinants.

BACKGROUND AND OBJECTIVE: The purpose of this study was to assess the defect width of infrabony defects in a cross-sectional study and to evaluate whether the defect width is a function of defect depth. MATERIAL AND METHODS: Complete sets of intra-oral radiographs of patients with severe periodontitis, which exhibited at least one infrabony defect, were digitised and evaluated. The following parameters were measured: depth and width of the infrabony defect, defect angle, and width of the interdental spaces. RESULTS: Fifty-one patients (26 women), ranging from 21 to 73 yr of age (48.5 +/- 13.4 yr), contributed a total of 1272 teeth with 135 infrabony defects (10.6%). Seventeen infrabony defects were located at sites without a neighboring tooth. Infrabony defects were statistically more prevalent in the mandible (n = 82) than in the maxilla (p = 0.013), and more prevalent at mesial sites (n = 92) than at distal sites (p < 0.001). At infrabony defects, the width of interdental spaces at the most coronal extension of the alveolar crest could be measured only at sites with neigboring teeth 2.67 +/- 0.78 mm (range: 1.19-5.70 mm). Analysis failed to reveal a statistically significant difference between defect width at sites with (2.64 +/- 0.82 mm) and sites without (2.76 +/- 0.70 mm) a neighboring tooth. Multilevel regression analysis revealed narrow defect angles to be related to deep infrabony defects, whereas width of the interdental space and distal location were related to wide defects. CONCLUSION: Defect angle depended on defect depth and defect width was not different at sites with or without a neighboring tooth. Even in severe periodontitis, infrabony defects are found only at a minority of teeth.

Adult↗

PubMed2005

Daily intake assessment of saccharin, stevioside, D-sorbitol and aspartame from various processed foods in Korea.

This study was carried out to estimate the daily intakes (EDIs) of artificial sweeteners such as saccharin, stevioside, D-sorbitol and aspartame in order to evaluate the safety of the artificial sweeteners in Korea. A total of 274 food samples were selected from the foods considered to be representative sources of artificial sweeteners in the Korean diet and analysed by using HPLC with evaporative light scattering and ultraviolet detectors. In case of aspartame, the reference values were used without instrumental analysis. The EDIs of saccharin, stevioside, D-sorbitol and aspartame for average consumers were 0.028, 0.008, 4.9 and 0.14 mg kg-1 body weight day-1, respectively, and as a proportion of the acceptable daily intake (ADI) were not higher than 1% of ADI of the Joint FAO/WHO Expert Committee on Food Additives (JECFA). For 90th percentile consumers, the EDIs of saccharin, stevioside, D-sorbitol and aspartame were 2.0, 0.20, 141 and 4.6 mg kg-1 body weight day-1, respectively, and as a proportion of the ADI, the EDIs of saccharin and aspartame were 40.7% and 11.4% of the ADI set by the JECFA, respectively. Because JECFA did not assign ADIs for stevioside and D-sorbitol, the values for these sweeteners were not compared. According to these results, the EDIs of artificial sweeteners such as saccharin and aspartame in Korea are significantly lower than ADI set by the JECFA.

Adolescent↗

PubMed2004

DNA sequence and comparative analysis of chimpanzee chromosome 22.

Human-chimpanzee comparative genome research is essential for narrowing down genetic changes involved in the acquisition of unique human features, such as highly developed cognitive functions, bipedalism or the use of complex language. Here, we report the high-quality DNA sequence of 33.3 megabases of chimpanzee chromosome 22. By comparing the whole sequence with the human counterpart, chromosome 21, we found that 1.44% of the chromosome consists of single-base substitutions in addition to nearly 68,000 insertions or deletions. These differences are sufficient to generate changes in most of the proteins. Indeed, 83% of the 231 coding sequences, including functionally important genes, show differences at the amino acid sequence level. Furthermore, we demonstrate different expansion of particular subfamilies of retrotransposons between the lineages, suggesting different impacts of retrotranspositions on human and chimpanzee evolution. The genomic changes after speciation and their biological consequences seem more complex than originally hypothesized.

Animals↗

PubMed2002

The plasma levels of interleukin-12 in schizophrenia, major depression, and bipolar mania: effects of psychotropic drugs.

Interleukin-12 (IL-12) plays a key role in promoting T helper 1 (Th1) responses and subsequent cell-mediated immunity. Given the role of cytokines in the pathogenesis of psychiatric disorders, the dysregulation of IL-12 in these illnesses would be expected. We measured the plasma levels of IL-12 in 102 psychiatric patients (43 schizophrenia, 34 major depression and 25 bipolar disorder) and 85 normal controls. In addition, IL-12 levels of the patients were measured after an 8-week treatment to assess whether the levels were affected by medication. The IL-12 levels of the patient group with major depression were significantly higher than that of the control group, whereas no differences were found among the other groups. IL-12 values of the three patient groups decreased significantly after 8 weeks of treatment. These findings support the hypothesis that activation of the inflammatory response system and in particular of Th-1-like cells, is involved in the pathophysiology of major depression and that repeated administration of antidepressive and antipsychotic drugs may suppress IL-12 plasma concentrations in psychiatric patients.

Adolescent↗