Publications by authors named "Kitai Kim"

Background: Phosphodiesterase 5 (PDE5) inhibitors, owing to their mechanism of action, have been gaining recognition as a potential case of drug repurposing and combination therapy for diabetes treatment. We aimed to examine the effect of long and short half-life PDE5 inhibitors have on Haemoglobin A1c (HbA1c) levels.

Methods: A systematic review and meta-analysis was conducted of randomised controlled trials (RCTs) in people with elevated HbA1c (>6%) to assess mean difference in HbA1c levels from baseline versus controls after any PDE5 inhibitor intervention of ≥4 weeks, excluding multiple interventions.

View Article and Find Full Text PDF

Background: Chromosomal translocation has been detected in many human cancers including gliomas and is considered a driving force in tumorigenesis. Co-deletion of chromosome arms 1p and 19q is a hallmark for oligodendrogliomas. On the molecular level, 1p/19q co-deletion results from t(1;19)(q10;p10), which leads to the concomitant formation of a hybrid chromosome containing the 1q and 19p arms.

View Article and Find Full Text PDF

Abstract: Roasting coffee results in not only the creation of carcinogens such as acrylamide, furan, and polycyclic aromatic hydrocarbons but also the elimination of carcinogens in raw coffee beans, such as endotoxins, preservatives, or pesticides, by burning off. However, it has not been determined whether the concentrations of these carcinogens are sufficient to make either light or dark roast coffee more carcinogenic in a living organism. An Ames test was conducted on light, medium, and dark roast coffee from three origins.

View Article and Find Full Text PDF
Article Synopsis
  • The study examines the link between anxiety and smartphone addiction among Korean adolescents, highlighting that excessive smartphone use can harm physical, social, and psychological health.
  • Using a survey of 1,733 adolescents, the research found that 20.1% of participants were categorized as high-risk for smartphone addiction, revealing significant differences in anxiety levels based on addiction risk.
  • Factors like poor self-reported health, fewer close friends, and substance use (caffeine and alcohol) were connected to higher anxiety, emphasizing the need for strategies to prevent smartphone addiction for better mental health.
View Article and Find Full Text PDF

Introduction: The aim of this study is to identify the association between Attention Deficit Hyperactivity Disorder (ADHD) proneness and aggressive propensity in adolescents.

Methods: A quantitative, large-scale, cross-sectional study was performed from April to May 2016 in Korea. The survey questionnaire included overall health behaviors, as well as scales for assessing ADHD proneness (revised short form of the Conners-Wells Adolescent Self-Report Scale; CASS[S]) and aggressive behavior (Buss-Perry Aggression Questionnaire; BPAQ) in adolescents.

View Article and Find Full Text PDF

In this study, we identified the health-related behaviors associated with aggression and examined the trends in both aggression and health-related behaviors among adolescents in the Republic of Korea. We used 2 cross-sectional samples of adolescents collected from the same geographic region 10 years apart. We measured aggression using the Aggression Questionnaire.

View Article and Find Full Text PDF

Background: The purpose of this study was to investigate the relationship between anxiety proneness and aggressive behavior in adolescents.

Methods: A quantitative, large scale cross-sectional study was conducted in Korea. The survey questionnaire included general health behavior and scales for assessing anxiety (Revised Children's Manifest Anxiety Scale; RCMAS) and aggressive behavior (The Aggression Questionnaire; AQ) in adolescents.

View Article and Find Full Text PDF

In the version of this Article originally published, Supplementary Fig. 6j showed incorrect values for the LS and AG4 glutathione samples, and Fig. 5c and Supplementary Fig.

View Article and Find Full Text PDF

Introduction: IDH1 mutation has been identified as an early genetic event driving low grade gliomas (LGGs) and it has been proven to exerts a powerful epigenetic effect. Cells containing IDH1 mutation are refractory to epigenetical reprogramming to iPSC induced by expression of Yamanaka transcription factors, a feature that we employed to study early genetic amplifications or deletions in gliomagenesis.

Methods: We made iPSC clones from freshly surgically resected IDH1 mutant LGGs by forced expression of Yamanaka transcription factors.

View Article and Find Full Text PDF

We discovered that induced pluripotent stem cell (iPSC) clones generated from aged tissue donors (A-iPSCs) fail to suppress oxidative phosphorylation. Compared to embryonic stem cells (ESCs) and iPSCs generated from young donors (Y-iPSCs), A-iPSCs show poor expression of the pluripotent stem cell-specific glucose transporter 3 (GLUT3) and impaired glucose uptake, making them unable to support the high glucose demands of glycolysis. Persistent oxidative phosphorylation in A-iPSCs generates higher levels of reactive oxygen species (ROS), which leads to excessive elevation of glutathione (a ROS-scavenging metabolite) and a blunted DNA damage response.

View Article and Find Full Text PDF

Pluripotent stem cells (PSCs) deficient for microRNAs (miRNAs), such as Dgcr8 or Dicer embryonic stem cells (ESCs), contain no mature miRNA and cannot differentiate into somatic cells. How miRNA deficiency causes differentiation defects remains poorly understood. Here, we report that miR-302 is sufficient to enable neural differentiation of differentiation-incompetent Dgcr8 ESCs.

View Article and Find Full Text PDF

The RNA exosome complex targets AU-rich element (ARE)-containing mRNAs in eukaryotic cells. We identified a transcription factor, ZSCAN10, which binds to the promoters of multiple RNA exosome complex subunits in pluripotent stem cells to maintain subunit gene expression. We discovered that induced pluripotent stem cell clones generated from aged tissue donors (A-iPSC) show poor expression of ZSCAN10, leading to poor RNA exosome complex expression, and a subsequent elevation in ARE-containing RNAs, including glutathione peroxidase 2 (Gpx2).

View Article and Find Full Text PDF

Induced pluripotent stem cells (iPSCs), which are used to produce transplantable tissues, may particularly benefit older patients, who are more likely to suffer from degenerative diseases. However, iPSCs generated from aged donors (A-iPSCs) exhibit higher genomic instability, defects in apoptosis and a blunted DNA damage response compared with iPSCs generated from younger donors. We demonstrated that A-iPSCs exhibit excessive glutathione-mediated reactive oxygen species (ROS) scavenging activity, which blocks the DNA damage response and apoptosis and permits survival of cells with genomic instability.

View Article and Find Full Text PDF

Neural stem cells (NSCs) have the capacity to differentiate into neurons, astrocytes, and oligodendrocytes, and therefore represent a promising donor tissue source for treating neurodegenerative diseases and repairing injuries of the nervous system. However, it remains unclear how canonical microRNAs (miRNAs), the subset of miRNAs requiring the Drosha-Dgcr8 microprocessor and the type III RNase Dicer for biogenesis, regulate NSCs. In this study, we established and characterized Dgcr8 NSCs from conditionally Dgcr8-disrupted mouse embryonic brain.

View Article and Find Full Text PDF

MicroRNAs (miRNAs) are important regulators of reprogramming of somatic cells into induced pluripotent stem cells (iPSCs); however, it is unclear whether miRNAs are required for reprogramming and whether miRNA activity as a whole facilitates reprogramming. Here we report on successful reprogramming of mouse fibroblasts and neural stem cells (NSCs) lacking Dgcr8, a factor required for the biogenesis of canonical miRNAs, by Yamanaka factors, albeit at decreased efficiencies. Though iPSCs derived from Dgcr8-deficient mouse fibroblasts or NSCs were able to self-renew and expressed pluripotency-associated markers, they exhibited poor differentiation potential into mature somatic tissues, similar to Dgcr8(-/-) embryonic stem cells.

View Article and Find Full Text PDF

Reprogramming of fibroblasts to induced pluripotent stem cells (iPSCs) entails a mesenchymal to epithelial transition (MET). While attempting to dissect the mechanism of MET during reprogramming, we observed that knockdown (KD) of the epithelial-to-mesenchymal transition (EMT) factor SNAI1 (SNAIL) paradoxically reduced, while overexpression enhanced, reprogramming efficiency in human cells and in mouse cells, depending on strain. We observed nuclear localization of SNAI1 at an early stage of fibroblast reprogramming and using mouse fibroblasts expressing a knockin SNAI1-YFP reporter found cells expressing SNAI1 reprogrammed at higher efficiency.

View Article and Find Full Text PDF

Embryonic stem cells (ESCs) have previously been reported to reprogram somatic cells following fusion. The resulting ES-somatic cell hybrids have been shown to adopt the transcriptional profile of ESCs, suggesting that the pluripotent program is dominant. ES-somatic cell hybrids have most characteristics of pluripotent cells in vitro; however, it remains unclear whether the somatic genome is an active partner in the hybrid cells or simply retained predominately as silent cargo.

View Article and Find Full Text PDF

Translational control plays a pivotal role in the regulation of the pluripotency network in embryonic stem cells, but its effect on reprogramming somatic cells to pluripotency has not been explored. Here, we show that eukaryotic translation initiation factor 4E (eIF4E) binding proteins (4E-BPs), which are translational repressors, have a multifaceted effect on the reprogramming of mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs). Loss of 4E-BP expression attenuates the induction of iPSCs at least in part through increased translation of p21, a known inhibitor of somatic cell reprogramming.

View Article and Find Full Text PDF

Background: The purpose of this study was to examine the association between Internet overuse and aggression.

Methods: A total of 2336 high school students (boys, 57.5%; girls, 42.

View Article and Find Full Text PDF

Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)--derived by ectopic expression of four reprogramming factors in donor somatic cells--are superior in terms of ethical use, histocompatibility, and derivation method.

View Article and Find Full Text PDF

Parthenogenesis is the process by which an oocyte develops into an embryo without fertilization. Parthenogenetic activation can be performed at various stages of meiosis, yielding embryos with a distinct genetic pattern of homozygousity and heterozygousity. The heterozygousity pattern specific to parthenogenetic embryonic stem (pES) cells derived from such embryos, can be predicted using genome-wide single nucleotide polymorphism (SNP) analysis to determine whether extrusion of the first or second polar body is prohibited.

View Article and Find Full Text PDF

We compared bona fide human induced pluripotent stem cells (iPSCs) derived from umbilical cord blood (CB) cells and neonatal keratinocytes (K). As a consequence of both incomplete erasure of tissue-specific methylation and aberrant de novo methylation, CB-iPSCs and K-iPSCs were distinct in genome-wide DNA methylation profiles and differentiation potential. Extended passage of some iPSC clones in culture did not improve their epigenetic resemblance to embryonic stem cells, implying that some human iPSCs retain a residual 'epigenetic memory' of their tissue of origin.

View Article and Find Full Text PDF

Epigenetic modifications must underlie lineage-specific differentiation as terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Haematopoiesis provides a well-defined model to study epigenetic modifications during cell-fate decisions, as multipotent progenitors (MPPs) differentiate into progressively restricted myeloid or lymphoid progenitors. Although DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs, a comprehensive DNA methylation map of haematopoietic progenitors, or of any multipotent/oligopotent lineage, does not exist.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_sessiondqecfurjumdrj6urs8t25b8i207ng5ph): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once