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Sang-Hee Lee

Publications and source records attributed to Sang-Hee Lee.

11 recordsLinked to original sources
PubMed2025

Precise progerin targeting using RfxCas13d: A therapeutic avenue for Hutchinson-Gilford progeria syndrome.

Hutchinson-Gilford progeria syndrome (HGPS), an extremely rare progressive genetic disorder, is caused by a point mutation in LMNA that induces progerin production, which disrupts cellular function and triggers premature aging and mortality. Despite extensive efforts, HPGS remains incurable. We successfully implemented a strategy using RfxCas13d to selectively target progerin mRNA at specific junction regions, without unintended cleavage and reduce its expression. This technique discriminated between normal lamin A and progerin, thus providing a safe and targeted therapeutic avenue to treat HGPS. Our approach effectively restored aberrant gene expression and progerin-induced cellular phenotypes, including senescence, mitochondrial dysfunction, and DNA damage in cells with HGPS and LMNAG608G/G608G mice. Notably, LMNAG608G/G608G mice exhibited improved progeroid phenotypes, suggesting a potential therapeutic application of this approach for other diseases resulting from abnormal RNA splicing.

Progeria↗
PubMed2006

Is human longevity a consequence of cultural change or modern biology?

Increased longevity, expressed as the number of individuals surviving to older adulthood, represents a key way that Upper Paleolithic Europeans differ from earlier European (Neandertal) populations. Here, we address whether longevity increased as a result of cultural/adaptive change in Upper Paleolithic Europe, or whether it was introduced to Europe as a part of modern human biology. We compare the ratio of older to younger adults (OY ratio) in an early modern human sample associated with the Middle Paleolithic from Western Asia with OY ratios of European Upper Paleolithic moderns and penecontemporary Neandertals from the same region. We also compare these Neandertals to European Neandertals. The difference between the OY ratios of modern humans of the Middle and Upper Paleolithic is large and significant, but there is no significant difference between the Neandertals and early modern humans of Western Asia. Longevity for the West Asian Neandertals is significantly more common than for the European Neandertals. We conclude that the increase in adult survivorship associated with the Upper Paleolithic is not a biological attribute of modern humans, but reflects important cultural adaptations promoting the demographic and material representations of modernity.

Adult↗
PubMed2006

A case of Staphylococcus aureus endocarditis after ear piercing in a patient with normal cardiac valve and a questionnaire survey on adverse events of body piercing in college students of Korea.

Body piercing in young adults is on the rise in western countries and also in Korea. It is usually practised by non-medical persons, and therefore frequently entails local adverse events. Serious complications, such as septic arthritis or infective endocarditis, are occasionally reported, but infective endocarditis in patients with normal cardiac valve is rare. We experienced a case of acute S. aureus endocarditis after ear piercing. Thereafter we studied the status and complications of body piercing in college students of Korea based on a questionnaire survey, and revealed that the rate of ear piercing is high (96.5%) and 61.3% of the pierced persons experience local complications.

Adolescent↗
PubMed2005

Habiline variation: a new approach using STET.

The problem of whether the hominid fossil sample of habiline specimens is comprised of more than one species has received much attention in paleoanthropology. The core of this debate has critical implications about when and how variation can be explained by taxonomy. In this paper, we examine the problem of whether the observed variation in habiline samples reflects species differences. We test the null hypothesis of no difference by examining the degree of variability in habiline sample in comparison with other single-species early hominid fossil samples from Sterkfontein and Swartkrans (Sterkfontein is earlier than the habiline sample, Swartkrans may be within the habiline time span). We developed a new method for this examination, which we call STandard Error Test of the null hypothesis of no difference (STET). Our sampling statistic is based on the standard error of the slope of regressions between pairs of specimens, relating all of the homologous measurements that each pair shares. We show that the null hypothesis for the habiline sample cannot be rejected. The similarities of specimen pairs within the habiline sample are not more than those observed between the specimens in the australopithecine samples we analyzed.

Animals↗
PubMed2005

Brief communication: Is variation in the cranial capacity of the Dmanisi sample too high to be from a single species?

This study uses data resampling to test the null hypothesis that the degree of variation in the cranial capacity of the Dmanisi hominid sample is within the range variation of a single species. The statistical significance of the variation in the Dmanisi sample is examined using simulated distributions based on comparative samples of modern humans, chimpanzees, and gorillas. Results show that it is unlikely to find the maximum difference observed in the Dmanisi sample in distributions of female-female pairs from comparative single-species samples. Given that two sexes are represented, the difference in the Dmanisi sample is not enough to reject the null hypothesis of a single species. Results of this study suggest no compelling reason to invoke multiple taxa to explain variation in the cranial capacity of the Dmanisi hominids.

Animals↗
PubMed2005

Purification and characterization of NADPH-dependent Cr(VI) reductase from Escherichia coli ATCC 33456.

A soluble Cr(VI) reductase was purified from the cytoplasm of Escherichia coli ATCC 33456. The molecular mass was estimated to be 84 and 42 kDa by gel filtration and SDS-polyacrylamide gel electrophoresis, respectively, indicating a dimeric structure. The pI was 4.66, and optimal enzyme activity was obtained at pH 6.5 and 37 degrees C. The most stable condition existed at pH 7.0. The purified enzyme used both NADPH and NADH as electron donors for Cr(VI) reduction, while NADPH was the better, conferring 61%; higher activity than NADH. The Km values for NADPH and NADH were determined to be 47.5 and 17.2 micromol, and the Vmax values 322.2 and 130.7 micromol Cr(VI) min(-1)mg(-1) protein, respectively. The activity was strongly inhibited by N-ethylmalemide, Ag2+, Cd2+, Hg2+, and Zn2+. The antibody against the enzyme showed no immunological cross reaction with those of other Cr(VI) reducing strains.

Amino Acid Sequence↗
PubMed2004

Older age becomes common late in human evolution.

Increased longevity, expressed as number of individuals surviving to older adulthood, represents one of the ways the human life history pattern differs from other primates. We believe it is a critical demographic factor in the development of human culture. Here, we examine when changes in longevity occurred by assessing the ratio of older to younger adults in four hominid dental samples from successive time periods, and by determining the significance of differences in these ratios. Younger and older adult status is assessed by wear seriation of each sample. Whereas there is significant increased longevity between all groups, indicating a trend of increased adult survivorship over the course of human evolution, there is a dramatic increase in longevity in the modern humans of the Early Upper Paleolithic. We believe that this great increase contributed to population expansions and cultural innovations associated with modernity.

Adult↗
PubMed2004

Acidic polysaccharide isolated from Phellinus linteus enhances through the up-regulation of nitric oxide and tumor necrosis factor-alpha from peritoneal macrophages.

Medicinal mushrooms are increasingly used to treat a wide variety of disease processes. Aqueous extract from the fruiting body or mycelia of Phellinus linteus has been reported to produce antitumor and immunomodulatory activities in vivo and in vitro. However, the mechanisms underlying its tumoricidal effects are poorly understood. The tumoricidal activity of peritoneal macrophages (PM) cultured with acidic polysaccharide (PL) isolated from Phellinus linteus against B16 melanoma cells was enhanced in a dose-dependent manner; growth inhibition increased 4-fold with 200 microg/ml of PL. To further characterize the mechanisms of PL, we investigated the effects of PL on phagocytosis and the release of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) and reactive oxygen intermediates (ROI). To investigate the phagocytosis of PM, the uptake of Dextran (Dex)-FITC between PL-untreated and PL-treated PM was compared. We found some augment in phagocytosis of PL-treated PM compared untreated group. PL stimulated a dose-dependent increase in NO and TNF-alpha, but not in ROI production in PM. We suggested that PL has cytotoxicity against Yac-1 cells through the up-regulation of NO and TNF-alpha production. Also, PL enhanced the expression of costimulatory molecules, CD80 and CD86, and major histocompatibility complex (MHC) molecules II in PM. The ability of PL upon the up-regulation of these surface molecules involved in antigen-presenting processes may, by inference, activate T-cell-mediated immunity against malignant cells in vivo. Taken together, these results suggest that PL act as an effective immunomodulator and enhances the anti-tumoral activity of PM.

Agaricales↗
PubMed2002

The late Neandertal supraorbital fossils from Vindija Cave, Croatia: a biased sample?

The late Neandertal sample from Vindija (Croatia) has been described as transitional between the earlier Central European Neandertals from Krapina (Croatia) and modern humans. However, the morphological differences indicating this transition may rather be the result of different sex and/or age compositions between the samples. This study tests the hypothesis that the metric differences between the Krapina and Vindija supraorbital samples are due to sampling bias. We focus upon the supraorbital region because past studies have posited this region as particularly indicative of the Vindija sample's transitional nature. Furthermore, the supraorbital region varies significantly with both age and sex. We analyzed four chords and two derived indices of supraorbital torus form as defined by Smith & Ranyard (1980, Am. J. phys. Anthrop.93, pp. 589-610). For each variable, we analyzed relative sample bias of the Krapina and Vindija samples using three sampling methods. In order to test the hypothesis that the Vindija sample contains an over-representation of females and/or young while the Krapina sample is normal or also female/young biased, we determined the probability of drawing a sample of the same size as and with a mean equal to or less than Vindija's from a Krapina-based population. In order to test the hypothesis that the Vindija sample is female/young biased while the Krapina sample is male/old biased, we determined the probability of drawing a sample of the same size as and with a mean equal or less than Vindija's from a generated population whose mean is halfway between Krapina's and Vindija's. Finally, in order to test the hypothesis that the Vindija sample is normal while the Krapina sample contains an over-representation of males and/or old, we determined the probability of drawing a sample of the same size as and with a mean equal to or greater than Krapina's from a Vindija-based population. Unless we assume that the Vindija sample is female/young and the Krapina sample is male/old biased, our results falsify the hypothesis that the metric differences between the Krapina and Vindija samples are due to sample bias.

Animals↗