Sung-Yong Lim

A PCR Analysis of ERα and ERβ mRNA Abundance in Rats and the Effect of Ovariectomy

To study the relative abundance and the changes of both estrogen receptor alpha (ERα) and ERβ mRNA before and after ovariectomy in major organs important to the regulation of calcium homeostasis, we compared the degree of mRNA expression of ERα to that of ERβ in rat tissues by performing competitive reverse transcription polymerase chain reaction (RT‐PCR) with internal standards. Both ERα and ERβ were highly expressed in the ovary {ERα[(2.2 ± 0.33) × 107 copies/μg of total RNA] > ERβ[(1.2 ± 0.33) × 105 copies/μg of total RNA]} as we expected. The bone marrow and renal cortex were very important target organs of estrogen because ERα was highly expressed ∼2 × 105 copies/μg of total RNA, but marrow cells revealed only a very weak expression of ERβ [(0.7 ± 0.21) × 102 copies/μg of total RNA]. Both ERα and ERβ were expressed in the trabecular bone [(3.2 ± 0.56) × 103 copy/μg of RNA] and [(2.8 ± 0.21) × 102 copy/μg of RNA], respectively. However, they were not detected in the cortical bone. In the jejunum, the expression of ERα was not detectable, while ERβ was expressed very weakly [(1.1 ± 0.24) × 102 copies/μg of total RNA]. The thyroid gland expressed low copy numbers of ERβ [(6.0 ± 0.23) × 102 copies/μg of total RNA], but the parathyroid gland was negative for both ERα and ERβ mRNA. In cultured stromal cells, ERα and ERβ mRNAs were not detected after a 24‐h culture; however, the rates of mRNA expression of ERα and ERβ reached ∼105 copies/μg of total RNA and ∼102 copies/μg of total RNA, respectively, after 9‐, 11‐, and 13‐day cultures. After ovariectomy, the expression of ERα mRNA decreased abruptly in the bone marrow and renal cortex, and both ERα and ERβ were barely detected in the trabecular bone. In conclusion, ERα might be the main ER in organs important for calcium homeostasis, except in the jejunum. The mRNA expression of ERα in the bone marrow and renal cortex decreased abruptly after ovariectomy, which may partially explain why the effect of estrogen deficiency can be amplified and why trabecular bone loss is more predominant than cortical bone loss shortly after surgical or natural menopause.

Polycystic ovarian syndrome (PCOS) and insulin resistance

Objectives: Polycystic ovary syndrome (PCOS) presents a high risk of developing type 2 diabetes mellitus. We studied a group of women with PCOS and evaluated this defect in insulin action. Methods: The study population consisted of nine PCOS women, six obese type 2 diabetic patients, and five controls whose body mass index (BMI) was similar to that of the nine PCOS women. The 75‐g oral glucose tolerance test (OGTT) and the hyperinsulinemic euglycemic glucose clamp test were performed. Clinical characteristics and the metabolic profiles, including the insulin sensitivity index (ISI), were compared. Results: PCOS women showed significantly elevated insulin responses during OGTT, but their blood glucose levels were comparable with the controls. The subjects with PCOS had more insulin resistance than the other groups. There was no difference among the groups in terms of clinical characteristics and metabolic profiles, except age, luteinzing hormone (LH), testosterone, and sex hormone binding globulin (SHBG). Conclusion: We conclude that PCOS women have significant insulin resistance which is independent of adiposity.

Insulin sensitivity in physically fit and unfit children of parents with Type 2 diabetes

Aims  First‐degree relatives of patients with Type 2 diabetes mellitus (T2DM) are often reported to be insulin resistant. We wanted to identify early metabolic abnormalities in this condition, and determine whether they are altered by regular physical training.

Mutation in hepatocyte nuclear factor-1α is not a common cause of MODY and early-onset type 2 diabetes in Korea

Abstract Maturity-onset diabetes of the young (MODY)-3 with a mutation in hepatocyte nuclear factor (HNF)-1α has been identified in most races, but the prevalence of Korean MODY and early-onset type 2 diabetes with a mutation in this gene is unknown. To determine the prevalence of MODY and early-onset type 2 diabetes with the mutation of HNF-1α gene in Korea, we analyzed this gene in 69 Korean early-onset type 2 diabetics and in 35 healthy persons using the single-strand conformation polymorphism (SSCP) technique and direct sequencing. We identified one mutation in exon 4 (C900A) in only one of the 69 Korean subjects with early-onset type 2 diabetes; this mutation was silent and did not change the amino acid (Pro300). Additionally, we identified four polymorphisms: S487N, AAC→AGC, intron 2 (nt −23), intron 7: (nt +7) and intron 9 (nt −24). However, there was no significant difference in frequencies of the four polymorphisms between the type 2 diabetes and control groups. Among type 2 diabetics, codon 487 variant showed no relationship to age at onset, body mass index, fasting blood glucose. HbA1c, lipid profile, basal C-peptide and 2 hour C-peptide. We concluded that this genetic mutation in HNF-1α gene may not be a common contributor to MODY and early-onset type 2 diabetes susceptibility in Korea.

Clinical characteristics, GAD antibody (GADA) and change of C-peptide in Korean young age of onset diabetic patients

Aims To investigate the association of clinical and immunological markers with diabetes classification in newly diagnosed young diabetic patients at disease onset.

Increasing the storage density of a page-based holographic data storage system by image upscaling using the PSF of the Nyquist aperture.

We introduce an image upscaling method that reduces bit errors caused by Nyquist apertures. Nyquist apertures used for higher storage densities generate optical aberrations and degrade the quality of the image that is recorded on the medium. Here, to correct the bit errors caused by the Nyquist aperture, an image upscaling method is used to restore the degraded image in the enhanced spatial frequency domain using its point spread function (PSF) as a restoration filter. The proposed method reduces the bit error rate (BER) significantly and hence allows higher storage densities.

Therapeutic effect of recombinant human erythropoietin on anaemia with erythropoietin deficiency in diabetic patients

Aims The aim of this study was to investigate the therapeutic effect of recombinant human erythropoietin (rHuEpo) on anaemia with erythropoietin deficiency in diabetic patients.

Line Tracking Applied Data Acquisition Method for Holographic Data Storage System

In a holographic data storage device, data are stored and retrieved as two-dimensional images. These images can be distorted in various ways. Generally, sync marks are used to acquire exact pixel values in a distorted image. However, this inevitably results in some loss of data density. In this research, a virtual detector that follows the rows of an image like a compact disk (CD) track is used to acquire the data pixels in a distorted image without sync marks. The proposed method can compensate for image distortion without any loss of data density. The feasibility of the new technique is demonstrated by simulation. The procedure is also evaluated on the basis of signal-to-noise ratio and bit error ratio.

Tilt measurement and compensation algorithm for holographic data storage with optimized quadratic windows

In holographic data storage, tilt is one of the critical disturbances. There are two types of tilt: tangential and radial. In real systems, tangential and radial tilt occur simultaneously. Thus, it is difficult to measure and compensate for tilt. In this study, using a quadratic window, which compares the intensity of a certain area, a tilt error signal was generated and compensated for with the proposed algorithm. The compensated image obtained satisfied a 0.3 dB tolerance.

Disturbances Analysis Considering an Effective Servo System for Holographic Disc Drive

In conventional angle-multiplexed holographic data storage, data pages are recorded and are retrieved with stop–go rotation. In this paper, we propose an effective servo method based on the disturbance analysis of holographic disc drives. Our experimental results indicate that the eccentricity and deviation of the disc provide sufficient information in the disturbance estimations to stabilize the servo system. The results also show that the vibration due to stop–go rotation can be ignored.