A Brain-Machine interface (BMI) allows for direct communication between the brain and machines. Neural probes for recording neural signals are among the essential components of a BMI system. In this report, we review research regarding implantable neural probes and their applications to BMIs. We first discuss conventional neural probes such as the tetrode, Utah array, Michigan probe, and electroencephalography (ECoG), following which we cover advancements in next-generation neural probes. These next-generation probes are associated with improvements in electrical properties, mechanical durability, biocompatibility, and offer a high degree of freedom in practical settings. Specifically, we focus on three key topics: (1) novel implantable neural probes that decrease the level of invasiveness without sacrificing performance, (2) multi-modal neural probes that measure both electrical and optical signals, (3) and neural probes developed using advanced materials. Because safety and precision are critical for practical applications of BMI systems, future studies should aim to enhance these properties when developing next-generation neural probes.
Brain ; Brain-Computer Interfaces* ; Electroencephalography ; Freedom ; Michigan ; Utah

PURPOSE: Near-infrared spectroscopy (NIRS) can noninvasively assess changes in tissue oxygen saturation (StO₂). The primary concern of the current study is to determine whether StO₂ can be used as a surrogate for global oxygenation parameters such as central venous oxygen saturation (ScvO₂), lactic acid, and base deficit (BD) in patients presenting to the emergency department (ED). METHODS: This was a prospective, observational study in patients requiring central venous catheter placement, admitted to the ED with complaints classified as infectious and non-infectious etiology. The NIRS sensor (15 mm probe) was applied on the thenar eminence for at least 3 minutes and ScvO₂, arterial lactic acid, and BD were measured during insertion of a central venous catheter. Data were analyzed using a simple correlation and Bland-Altman plot. RESULTS: A total of 120 patients were enrolled in the study and further classified as an infection (n=39) and a noninfection (n=81) group. Lactic acid BD showed significant correlation with StO₂ in total and in non-infection patients but the degree of correlation was weak and these correlations were not observed in infection patients. Approximately 94% of the difference between StO₂ and ScvO₂ was placed within limit of agreement but there was a risk that StO₂ may overestimate ScvO₂ when ScvO₂ becomes lower. When patients were assigned to two groups according to laboratory results (lactic acid 4.0 mmol/L; BD > 3.0 mmol/L; ScvO₂> 65% or 75%), no significant difference in StO₂ was observed between the two groups. CONCLUSION: In ED patients suspected of having systemic hypoperfusion, StO₂ showed a weak correlation with lactic acid and BD in non-infection patients and no correlation in infection patients. In addition, as ScvO₂ decreased, the difference between StO₂ and ScvO₂ showed a tendency to increase, and StO₂ was much higher than ScvO₂ at low ScvO₂ level. Therefore, before using StO₂ as surrogate for ScvO₂, lactic acid and BD in critically ill patients presenting to the ED, further investigation should be conducted to overcome the limitations of NIRS addressed in this study.
Central Venous Catheters ; Clinical Study* ; Critical Illness ; Emergencies* ; Emergency Service, Hospital ; Humans ; Lactic Acid ; Microcirculation ; Observational Study ; Oxygen* ; Prospective Studies ; Spectroscopy, Near-Infrared

PURPOSE: Conventional methods for the prenatal detection of fetal RhD status involve invasive procedures such as fetal blood sampling and amniocentesis. The identification of cell-free fetal DNA (cffDNA) in maternal plasma creates the possibility of determining fetal RhD status by analyzing maternal plasma DNA. However, some technical problems still exist, especially the lack of a positive control marker for the presence of fetal DNA. Therefore, we assessed the feasibility and accuracy of fetal RHD genotyping incorporating the RASSF1A epigenetic fetal DNA marker from cffDNA in the maternal plasma of RhD-negative pregnant women in Korea. MATERIALS AND METHODS: We analyzed maternal plasma from 41 pregnant women identified as RhD-negative by serological testing. Multiplex real-time PCR was performed by amplifying RHD exons 5 and 7 and the SRY gene, with RASSF1A being used as a gender-independent fetal epigenetic marker. The results were compared with those obtained by postnatal serological analysis of cord blood and gender identification. RESULTS: Among the 41 fetuses, 37 were RhD-positive and 4 were RhD-negative according to the serological analysis of cord blood. There was 100% concordance between fetal RHD genotyping and serological cord blood results. Detection of the RASSF1A gene verified the presence of cffDNA, and the fetal SRY status was correctly detected in all 41 cases. CONCLUSION: Noninvasive fetal RHD genotyping with cffDNA incorporating RASSF1A is a feasible, reliable, and accurate method of determining fetal RhD status. It is an alternative to amniocentesis for the management of RhD-negative women and reduces the need for unnecessary RhIG prophylaxis.
Amniocentesis ; DNA* ; Epigenomics ; Exons ; Female ; Fetal Blood ; Fetus ; Genes, sry ; Genetic Markers ; Humans ; Korea* ; Plasma ; Pregnant Women* ; Prenatal Diagnosis ; Real-Time Polymerase Chain Reaction ; Serologic Tests

PURPOSE: Noninvasive prenatal test (NIPT) by massively parallel sequencing (MPS) of cell-free fetal DNA in maternal plasma marks a significant advancement in prenatal screening, minimizing the need for invasive testing of fetal chromosomal aneuploidies. Here, we report the initial clinical performance of NIPT in Korean pregnant women. MATERIALS AND METHODS: MPS-based NIPT was performed on 910 cases; 5 mL blood samples were collected and sequenced in the Shenzhen BGI Genomic Laboratory to identify aneuploidies. The risk of fetal aneuploidy was determined by L-score and t-score, and classified as high or low. The NIPT results were validated by karyotyping for the high-risk cases and neonatal follow-up for low-risk cases. RESULTS: NIPT was mainly requested for two clinical indications: abnormal biochemical serum-screening result (54.3%) and advanced maternal age (31.4%). Among 494 cases with abnormal biochemical serum-screening results, NIPT detected only 9 (1.8%) high-risk cases. Sixteen cases (1.8%) of 910 had a high risk for aneuploidy: 8 for trisomy 21, 2 for trisomy 18, 1 for trisomy 13, and 5 for sex chromosome abnormalities. Amniocentesis was performed for 7 of these cases (43.8%). In the karyotyping and neonatal data, no false positive or negative results were observed in our study. CONCLUSION: MPS-based NIPT detects fetal chromosomal aneuploidies with high accuracy. Introduction of NIPT as into clinical settings could prevent about 98% of unnecessary invasive diagnostic procedures.
Amniocentesis ; Aneuploidy* ; DNA* ; Down Syndrome ; Female ; Follow-Up Studies ; High-Throughput Nucleotide Sequencing* ; Humans ; Karyotyping ; Korea* ; Maternal Age ; Plasma* ; Pregnant Women ; Prenatal Diagnosis ; Sex Chromosome Aberrations ; Trisomy

PURPOSE: The mutation of the SLC26A4 gene is the second most common cause of congenital hearing loss after GJB2 mutations. It has been identified as a major cause of autosomal recessive nonsyndromic hearing loss associated with enlarged vestibular aqueduct and Pendred syndrome. Although most studies of SLC26A4 mutations have dealt with hearing-impaired patients, there are a few reports on the frequency of these mutations in the general population. The purpose of this study was to evaluate the prevalence of SLC26A4 mutations that cause inherited deafness in the general Korean population. MATERIALS AND METHODS: We obtained blood samples from 144 Korean individuals with normal hearing. The samples were subjected to polymerase chain reaction to amplify the entire coding region of the SLC26A4 gene, followed by direct DNA sequencing. RESULTS: Sequencing analysis of this gene identified 5 different variants (c.147C>G, c.225G>C, c.1723A>G, c.2168A>G, and c.2283A>G). The pathogenic mutation c.2168A>G (p.H723R) was identified in 1.39% (2/144) of the subjects with normal hearing. CONCLUSION: These data provide information about carrier frequency for SLC26A4 mutation-associated hearing loss and have important implications for genetic diagnostic testing for inherited deafness in the Korean population.
Clinical Coding ; Deafness* ; Diagnostic Tests, Routine ; Hearing ; Hearing Loss ; Humans ; Polymerase Chain Reaction ; Prevalence ; Sequence Analysis, DNA ; Vestibular Aqueduct

The effectiveness of three kinds of enzymes (chitinase, beta-glucuronidase, and lysing enzyme complex), employed as elicitors to enhance the beta-glucan content in the sawdust-based cultivation of cauliflower mushroom (Sparassis latifolia), was examined. The elicitors were applied to the cauliflower mushroom after primordium formation, by spraying the enzyme solutions at three different levels on the sawdust-based medium. Mycelial growth was fully accomplished by the treatments, but the metabolic process during the growth of fruiting bodies was affected. The application of a lysing enzyme resulted in an increase in the beta-glucan concentration by up to 31% compared to that of the control. However, the treatment resulted in a decrease in mushroom yield, which necessitated the need to evaluate its economic efficiency. Although we still need to develop a more efficient way for using elicitors to enhance functional metabolites in mushroom cultivation, the results indicate that the elicitation technique can be applied in the cultivation of medicinal/edible mushrooms.
Agaricales* ; Brassica* ; Fruit ; Glucuronidase ; Metabolism

BACKGROUND: Glucose toxicity that is caused by chronic exposure to a high glucose concentration leads to islet dysfunction and induces apoptosis in pancreatic beta-cells. Heme oxygenase-1 (HO-1) has been identified as an anti-apoptotic and cytoprotective gene. The purpose of this study is to investigate whether HO-1 up-regulation when using metalloprotophyrin (cobalt protoporphyrin, CoPP) could protect pancreatic beta-cells from high glucose-induced apoptosis. METHODS: Reverse transcription-polymerase chain reaction was performed to analyze the CoPP-induced mRNA expression of HO-1. Cell viability of INS-1 cells cultured in the presence of CoPP was examined by acridine orange/propidium iodide staining. The generation of intracellular reactive oxygen species (ROS) was measured using flow cytometry. Glucose stimulated insulin secretion (GSIS) was determined following incubation with CoPP in different glucose concentrations. RESULTS: CoPP increased HO-1 mRNA expression in both a dose- and time-dependent manner. Overexpression of HO-1 inhibited caspase-3, and the number of dead cells in the presence of CoPP was significantly decreased when exposed to high glucose conditions (HG). CoPP also decreased the generation of intracellular ROS by 50% during 72 hours of culture with HG. However, decreased GSIS was not recovered even in the presence of CoPP. CONCLUSION: Our data suggest that CoPP-induced HO-1 up-regulation results in protection from high glucose-induced apoptosis in INS-1 cells; however, glucose stimulated insulin secretion is not restored.
Apoptosis ; Caspase 3 ; Cell Survival ; Diabetes Mellitus ; Flow Cytometry ; Glucose ; Heme ; Heme Oxygenase-1 ; Insulin ; Protoporphyrins ; Reactive Oxygen Species ; RNA, Messenger ; Up-Regulation

PURPOSE: Quantitative fluorescent polymerase chain reaction (QF-PCR) allows for the rapid prenatal diagnosis of common aneuploidies. The main advantages of this assay are its low cost, speed, and automation, allowing for large-scale application. However, despite these advantages, it is not a routine method for prenatal aneuploidy screening in Korea. Our objective in the present study was to validate the performance of QF-PCR using short tandem repeat (STR) markers in a Korean population as a means for rapid prenatal diagnosis. MATERIALS AND METHODS: A QF-PCR assay using an Elucigene kit (Gen-Probe, Abingdon, UK), containing 20 STR markers located on chromosomes 13, 18, 21, X and Y, was performed on 847 amniotic fluid (AF) samples for prenatal aneuploidy screening referred for prenatal aneuploidy screening from 2007 to 2009. The results were then compared to those obtained using conventional cytogenetic analysis. To evaluate the informativity of STR markers, the heterozygosity index of each marker was determined in all the samples. RESULTS: Three autosomes (13, 18, and 21) and X and Y chromosome aneuploidies were detected in 19 cases (2.2%, 19/847) after QF-PCR analysis of the 847 AF samples. Their results are identical to those of conventional cytogenetic analysis, with 100% positive predictive value. However, after cytogenetic analysis, 7 cases (0.8%, 7/847) were found to have 5 balanced and 2 unbalanced chromosomal abnormalities that were not detected by QF-PCR. The STR markers had a slightly low heterozygosity index (average: 0.76) compared to those reported in Caucasians (average: 0.80). Submicroscopic duplication of D13S634 marker, which might be a unique finding in Koreans, was detected in 1.4% (12/847) of the samples in the present study. CONCLUSION: A QF-PCR assay for prenatal aneuploidy screening was validated in our institution and proved to be efficient and reliable. However, we suggest that each laboratory must perform an independent validation test for each STR marker in order to develop interpretation guidelines of the results and must integrate QF-PCR into the routine cytogenetic laboratory workflow.
Amniotic Fluid ; Aneuploidy ; Automation ; Chromosome Aberrations ; Cytogenetic Analysis ; Cytogenetics ; Female ; Korea ; Mass Screening ; Microsatellite Repeats ; Polymerase Chain Reaction ; Prenatal Diagnosis ; Y Chromosome

BACKGROUND: Despite a recent breakthough in human islet transplantation for treating type 1 diabetes mellitus, the limited availability of donor pancreases remains a major obstacle. Endocrine cells within the gut epithelium (enteroendocrine cells) and pancreatic beta cells share similar pathways of differentiation during embryonic development. In particular, K-cells that secrete glucose-dependent insulinotropic polypeptide (GIP) have been shown to express many of the key proteins found in beta cells. Therefore, we hypothesize that K-cells can be transdifferentiated into beta cells because both cells have remarkable similarities in their embryonic development and cellular phenotypes. METHODS: K-cells were purified from heterogeneous STC-1 cells originating from an endocrine tumor of a mouse intestine. In addition, a K-cell subclone expressing stable Nkx6.1, called "Kn4-cells," was successfully obtained. In vitro differentiation of K-cells or Kn4-cells into beta cells was completed after exendin-4 treatment and serum deprivation. The expressions of insulin mRNA and protein were examined by RT-PCR and immunocytochemistry. The interacellular insulin content was also measured. RESULTS: K-cells were found to express glucokinase and GIP as assessed by RT-PCR and Western blot analysis. RT-PCR showed that K-cells also expressed Pdx-1, NeuroD1/Beta2, and MafA, but not Nkx6.1. After exendin-4 treatment and serum deprivation, insulin mRNA and insulin or C-peptide were clearly detected in Kn4-cells. The intracellular insulin content was also increased significantly in these cells. CONCLUSION: K-cells are an attractive potential source of insulin-producing cells for treatment of type 1 diabetes mellitus. However, more experiments are necessary to optimize a strategy for converting K-cells into beta cells.
Animals ; Blotting, Western ; C-Peptide ; Diabetes Mellitus, Type 1 ; Embryonic Development ; Endocrine Cells ; Enteroendocrine Cells ; Epithelium ; Female ; Glucokinase ; Humans ; Immunohistochemistry ; Insulin ; Insulin-Secreting Cells ; Intestines ; Islets of Langerhans Transplantation ; Mice ; Pancreas ; Peptides ; Phenotype ; Pregnancy ; Proteins ; RNA, Messenger ; Tissue Donors ; Venoms

PURPOSE: p63 is a recently described as p53 homologue. Despite their structural homologies, they have different activities. p63 is a specific myoepithelial cell marker in normal breast tissue and it is expressed in a minority of breast cancers. The aim of this study was to evaluate the prognostic significance of the p63 expression in breast cancer. METHODS: The expression of p63 in breast cancer was determined by performing immunohistochemistry on 350 patients who underwent mastectomy at the Department of Surgery at Korea University Medical Center between January 1992 and September 2004. A retrospective analysis was conducted using the medical records. A tissue microarray was constructed, and immunohistochemical analysis for p63 was performed according to the usual methods. RESULTS: Among 350 patients, 40 (11.4%) showed a p63 expression. There was a significant correlation between p63 and the histologic grade. There were significant correlations of p63 with p53 and HER2/neu, respectively. In the basal type of breast cancer, the p63 expression was significantly higher than in the luminal type of breast cancer. The 5 year disease free survival rates were 69% in the patients with a p63 expression and 76% in the patients without a p63 expression, but there was no statistical difference. CONCLUSION: The present results indicate that a p63 expression is associated with a high grade tumor, a p53 expression and a HER2/neu expression in breast cancer, which are the known poor prognostic factors of breast cancer. Immunohistochemical subtyping shows that the p63 expression is a useful predictor for the basal type of breast cancer. In addition, this study suggests that the p63 expression in the basal type of breast cancer is associated with a poor prognosis.
Academic Medical Centers ; Breast Neoplasms* ; Breast* ; Disease-Free Survival ; Humans ; Immunohistochemistry ; Korea ; Mastectomy ; Medical Records ; Phenobarbital ; Prognosis ; Retrospective Studies