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Biomedical subjects

J S Hwang

Publications and source records attributed to J S Hwang.

At least 19 recordsLinked to original sources
PubMed2006

Teriparatide vs. calcitonin in the treatment of Asian postmenopausal women with established osteoporosis.

This study compared the clinical efficacy, safety, and tolerability of daily subcutaneous injections of teriparatide and salmon calcitonin in the treatment of postmenopausal women with established osteoporosis in Taiwan. This 6-month, multicenter, randomized, controlled study enrolled 63 women with established osteoporosis. They were randomized to receive either teriparatide 20 microg or calcitonin 100 IU daily in an open-label fashion. Lumber spine, femoral neck, total hip bone mineral density (BMD), and biochemical markers of bone turnover were measured, and adverse events and tolerability were recorded. The results at 6 months showed that patients using teriparatide had larger mean increases in spinal BMD than those who used calcitonin (4.5% vs. 0.1%), but the BMD changes in these two groups at the femoral neck and the total hip were not significant. There were also larger mean increases in bone markers in the teriparatide group than in the calcitonin group (bone specific alkaline phosphatase 142% vs. 37%; osteocalcin 154% vs. 23%). We conclude that teriparatide has more positive effects on bone formation than salmon calcitonin, as shown by the larger increments of lumbar spine BMD and bone formation markers, and caused only mild adverse events and no significant change in liver, kidney or hematological parameters. Compared with the published global results, teriparatide seems to be equally effective and safe to use in this Asian population.

Aged↗
PubMed2006

The dermal stem cell factor and c-kit are overexpressed in melasma.

BACKGROUND: The pathogenesis of melasma has not yet been clearly demonstrated. We tried to determine whether the stem cell factor (SCF) and its receptor c-kit are involved in the mechanism of hyperpigmentation of melasma because this factor is highly implicated in the stimulation of melanocyte function in vitro and in vivo. OBJECTIVES: The present study was conducted to investigate the expression of SCF and c-kit on the lesions of melasma compared with nonlesional skin. PATIENTS/METHODS: Skin samples were obtained from lesional and nonlesional facial skin of 60 Korean women with melasma. Immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to determine the expression of SCF and c-kit in melasma. RESULTS: The expression of SCF was significantly increased at the lesional dermis compared with nonlesional dermis. However, there was no significant difference in the expression of SCF in lesional and nonlesional epidermis. The expression of c-kit was significantly increased at lesional epidermis compared with nonlesional skin. RT-PCR of SCF and c-kit mRNAs demonstrated increased expression of both types of transcripts in the lesional skin compared with nonlesional skin. CONCLUSIONS: These results suggest that the increased expression of SCF in the dermis and of c-kit in the epidermis play an important role in the mechanism of hyperpigmentation in melasma.

Adult↗
PubMed2006

The mitochondrial genome of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae).

We determined the complete nucleotide sequences of the mitochondrial genome (mitogenome) of the Korean hairstreak, Coreana raphaelis (Lepidoptera: Lycaenidae). The entire mitochondrial DNA (mtDNA) molecule was 15,314 bp long. The C. raphaelis genes were in the same order and orientation as the completely sequenced mitogenomes of other lepidopteran species, except for the presence of an extra copy of tRNA(Ser)(AGN). High similarity in primary sequence and secondary structure between the two tandemly located copies of the tRNA(Ser)(AGN) suggest a recent duplication of an original single tRNA(Ser)(AGN). The DHU arm of the two copies of tRNA(Ser)(AGN) formed a simple loop as seen in many other metazoan mt tRNA(Ser)(AGN). The putative initiation codon for the C. raphaelis COI gene appears to be a tetranucleotide, TTAG, found commonly in the sequenced lepidopterans. ATPase8, ATPase6, ND4L and ND6 genes, which are next to another protein-coding gene at their 3' end all had the sequences potential to form a hairpin structure, suggesting the importance of such a structure for precise cleavage of the mature protein-coding genes.

AT Rich Sequence↗
PubMed2005

Clinical implications of N epsilon-(carboxymethyl)lysine, advanced glycation end product, in children and adolescents with type 1 diabetes.

AIM: The aim of this study was to investigate the relationship between serum levels of the glycoxylation product N(epsilon)-(carboxymethyl)lysine (CML) and development of chronic diabetic complications and degree of diabetic control in children and adolescents with type 1 diabetes. METHODS: The serum levels of CML were measured in 87 patients with uncomplicated type 1 diabetes mellitus (12.7 +/- 4.6 years of age) and in seven patients with background retinopathy, microalbuminuria or neuropathy (18.2 +/- 5.2 years of age) and compared with those in 64 normal control subjects (12.6 +/- 5.2 years of age). The mean durations of diabetes in uncomplicated and complicated patients were 5.0 +/- 3.4 years (0.1-14 years), and 8.6 +/- 5.0 years (3.1-18 years), respectively. The serum levels of CML were measured by enzyme-linked immunosorbent assay using a monoclonal anti-CML antibody (6D12). RESULTS: The serum levels of CML were significantly higher in the patient group than those in the control group; 0.85 +/- 0.37 (0.37-1.93) U/ml vs. 0.56 +/- 0.23 (0.15-1.05) U/ml (p < 0.001) and significantly higher in the patient group with chronic complications than those in patient group without chronic complications; 1.06 +/- 0.39 (0.72-1.78) U/ml vs. 0.83 +/- 0.36 (0.37-1.93) U/ml (p < 0.05). Weak, but statistically significant relationship between CML levels and haemoglobin A(1c) levels at the measurement of CML was observed (r = 0.29, p < 0.05). CONCLUSIONS: Our data are suggesting that higher serum levels of CML are involved in the development of chronic diabetic complications, and serum levels of CML reflect the degree of diabetic control for a long duration in type 1 diabetic children and adolescents.

Adolescent↗
PubMed2004

Effect of artificial cells on hepatic function after ischemia-reperfusion injury in liver.

BACKGROUND: The liver suffers from ischemia/reperfusion injury during transplantation. Reactive oxygen species generated by xanthine oxidase during reperfusion of the ischemic liver may be partially responsible for the hepatic injury. Oxygen free radicals are removed by antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase. Using glutaraldehyde and lysine we constructed crosslinked hemoglobin, containing SOD and catalase, and assessed its ability to protect against ischemia/reperfusion injury during transplantation. METHODS: In contrast to the sham-operated control groups, blood was exchanged using crosslinked hemoglobin (polyHb) a PolyHb-SOD-catalase (PSC) group. After ischemia/reperfusion injury, several parameters of hepatic damage and oxygen free radicals were measured as well as microscopic examination. RESULTS: Alanine aminotransferase, aspartate aminotransferase, superoxide production, hydrogen peroxide, and malondialdehyde levels were higher among the PolyHb group than sham-operated controls. The PolyHb group revealed a few apoptotic bodies, some acute inflammatory infiltrates in the sinusoids, nuclear fragmentations, cell shrinkage, and chromatin clumping with formation of apoptotic bodies in the apoptotic cells under microscopic examination. Alanine aminotransferase, aspartate aminotransferase, superoxide production, and hydrogen peroxide levels were lower in the PSC than the PolyHb group. Hepatic structures were well preserved in the PSC group. CONCLUSIONS: Reactive oxygen species contribute to hepatic dysfunction with morphologic changes. PSC is effective to reduce hepatic damage by lowering oxygen free radical-mediated injury after ischemia/reperfusion in the liver.

Animals↗
PubMed2004

Effects of polyhemoglobin-antioxidant enzyme complex on ischemia-reperfusion in kidney.

INTRODUCTION: The kidney suffers ischemia-reperfusion (I/R) injury during transplantation. The purpose of the present study was to investigate the therapeutic effect of artificials cells on renal I/R injury through biochemical assays and histological examination. METHODS: We prepared artificial cells using cross-linked hemoglobin (Hb), superoxide dismutase (SOD), and catalase. Normal male Sprague-Dawley rats were divided into 6 groups: the sham-operated control group, the group treated with polyHb,and the group treated with polyHb-SOD-catalase (PSC) (per groups were subjected to ischemia for 1 hour or 2 hours). After reperfusion for 4 hours, kidney and blood samples were obtained. RESULTS: The levels of SOD and catalase in the PSC group were 15 and 50 times higher than those of the control group, respectively. In the polyHb group, the levels of blood urea nitrogen (BUN), serum creatinine, renal hydrogen peroxide, and renal malondialdehyde were increased. However, their levels were significantly decreased by PSC administration. Renal SOD activity did not show any significant changes in the polyHb group, but renal catalase activity was decreased by polyHb treatment in comparison with the control group. The activities of renal SOD and catalase were increased using PSC treatment. In the histological findings, the PSC group showed no evidence of acute tubular necrosis in proximal convoluted tubules; their microvilli and cytoplasmic microorganelles were relatively well preserved. CONCLUSIONS: These results show that PSC effectively reduces renal damage via diminished oxygen free radical-mediated injury after I/R.

Animals↗
PubMed2004

Pigment-lightening effect of N,N'-dilinoleylcystamine on human melanoma cells.

BACKGROUND: Cystamine and linoleic acid have been reported to reduce melanin synthesis in vitro and in vivo. N,N'-dilinoleylcystamine (DLC) is a compound of cystamine and linoleic acid connected by an ester bond. OBJECTIVES: To investigate the effects of DLC on melanin synthesis using cultured human melanoma cells. METHODS: Levels of total melanin, eumelanin and phaeomelanin, tyrosinase protein and tyrosinase activity in situ were measured in HM3KO melanoma cells. Changes in degree of pigmentation were quantified by image analysis and compared with absorbance values. Tyrosinase from HM3KO cells was used to measure the direct effect of DLC on DOPA and DOPAchrome production. RESULTS: At concentrations of 1.4-14 micromol L-1, DLC reduced the pigmentation of HM3KO melanoma cells but did not affect cell growth. The visual decrease in pigmentation produced by DLC was more dramatic than the decrease in total melanin content as measured by absorbance at 500 nm. DLC treatment decreased eumelanin synthesis and increased phaeomelanin synthesis in HM3KO melanoma cells. An in situ tyrosinase assay showed that DLC inhibited tyrosinase activity, as well as the level of tyrosinase protein. CONCLUSIONS: These results suggest that DLC has pigment-lightening effects on HM3KO melanoma cells, produced by reducing the level of eumelanin while increasing the level of phaeomelanin.

Blotting, Western↗
PubMed2003

Wax moth, Galleria mellonella, high density lipophorin receptor: alternative splicing, tissue-specific expression, and developmental regulation.

A lipophorin (Lp) receptor cDNA from the fat body of Galleria mellonella (Lepidoptera) was cloned and sequenced. This is the first result in this order, Lepidoptera. It showed the pattern of the VLDL receptor belonging to the LDL receptor family. Sequence homology with other Lp receptors in insects, Locusta migratoria and Aedes aegypti, was 70 and 61%, respectively and each domain was highly conserved. Polyclonal anti-Lp receptor antibody prepared against expressed Lp receptor fragment between ligand binding domain and EGF-precursor homology domain (R305-D549 of amino acid residues) specifically detected the Lp receptor. Through immuno-blotting, the Lp receptor of larval fat body has an approximate molecular mass of about 97 and 110 kDa under non-reducing and reducing conditions, respectively. This result was in agreement with that of the ligand-blotting. The variant Lp receptors were expressed in the fat body of G. mellonella; one is an Lp receptor which lacks 84 bp of O-linked sugar domain and the other is a full length form of the Lp receptor. Both forms were detected by the polyclonal anti-Lp receptor antibody. The Lp receptor from the fat body of G. mellonella was differently expressed depending on the tissue and the developmental stage with specific abundance in prepupal stage. A steroid hormone, 20-hydroxyecdysone (20-HE) plays a crucial role in insect development. With regards to this conception, day 1-2 last instar larvae were treated with 20-HE and drastic induction of the Lp receptor was observed 48 h after treatment. It was also observed that cholesterol caused an induction of the Lp receptor.

Amino Acid Sequence↗
PubMed2002

An efficient motion estimation and compensation method for ultrasound synthetic aperture imaging.

This paper describes a method for overcoming motion artifacts in synthetic aperture imaging. The method is based on a computer simulation study on the influence of target motion on synthetic aperture techniques. A region-based motion compensation approach is used in which only the axial motion is estimated and compensated for a given region of interest under the assumption that the whole ROI moves uniformly. The estimated axial motion is calculated with a crosscorrelation method at the point where the focused signal has the maximum energy within the ROI. We also present a method for estimating axial motion using the autocorrelation method that is widely used to estimate average Doppler frequency. Both computer simulations and in vivo experiments show that the proposed crosscorrelation-based method can greatly improve the spatial resolution and SNR of ultrasound imaging by implementing SA techniques for two-way dynamic focusing without motion artifacts. In addition, the autocorrelation-based motion compensation method provides almost the same results as the crosscorrelation-based method, but with a dramatically reduced computational complexity.

Adult↗
PubMed2001

Rac and p38 kinase mediate 5-lipoxygenase translocation and cell death.

5-Lipoxygenase (5-LO) is a key enzyme involved in the synthesis of leukotrienes from arachidonic acid, and its activation is usually followed by translocation to the nuclear envelope. The details of mechanisms involved in the translocation of 5-LO are not well understood, though Ca(2+) is known to be essential. Here we show that ionomycin, a Ca(2+) ionophore, induces 5-LO translocation and necrotic cell death in Rat-2 fibroblasts, suggesting a potential relationship between activation of 5-LO and cell death. These effects were markedly attenuated in Rat2-Rac(N17) cells expressing a dominant negative Rac1 mutant. Pretreatment with SB203580, a specific inhibitor of p38 MAP kinase, or EGTA, a Ca(2+) chelator, likewise diminished ionomycin-induced 5-LO translocation and cell death, but PD98059, a MEK inhibitor, did not. Thus, Rac and p38 MAP kinase appear to be components in a Ca(2+)-dependent pathway leading to 5-LO translocation and necrotic cell death in Rat-2 fibroblasts.

Animals↗
PubMed2001

Improvement of gene transfer to cervical cancer cell lines using non-viral agents.

Virus-like particles (VLPs) composed of recombinant capsid protein L1 and L2 of human papillomavirus type 16 were conjugated with polylysine (PL) and gene transfer was performed using VLP-PL conjugates to allow the expression of targeted gene. When HeLa cells were incubated with VLP-PL conjugate coupled with plasmid cytomegalovirus beta-galactosidase (pCMVbeta-gal), about 10% of cells were transfected and demonstrated beta-galactosidase activity. Hence chloramphenicol acetyltransferase activity was also expressed significantly in VLP-PL-plasmid simian virus 2 chloramphenicol acetyl transferase (pSV2CAT)-transfected cells, VLP-PL conjugate was tested whether it could transfer a tumor suppressor gene, pCMVp53, to HeLa cells and the exogenously provided p53 gene complexed to VLP-PL conjugate was detected from HeLa cells by polymerase chain reaction (PCR) analysis. Interestingly, additional increase of transfection efficiency was demonstrated in the presence of poloxamer 407 when C-33A cells were transfected with VLP-PL-pCMVbeta-gal complex. The result support the notion that VLP-PL conjugate may be a promising vector to transfer genetic materials into cancer cells and poloxamer 407 can be used for enhancing the transfection efficiency of VLP-PL conjugate.

Capsid↗
PubMed2001

Isolation, identification and field tests of the sex pheromone of the carambola fruit borer, Eucosma notanthes.

Two components, (Z)-8-dodecenyl acetate (Z8-12:Ac) and (Z)-8-dodecenol (Z8-12:OH), were isolated from sex pheromone glands of the carambola fruit borer, Eucosma notanthes, and were identified by GC, and GC-MS, chemical derivatization, and comparison of retention times. The ratio of the alcohol to acetate in the sex pheromone extracts was 2.7. However, synthetic mixtures (1 mg) in ratios ranging from 0.5 to 1.5 were more effective than other blends in trapping male moths in field tests.

Animals↗
PubMed2001

Physical heights of children with prolonged low dose-rate gamma-radiation exposure in radiocontaminated buildings.

PURPOSE: To evaluate low dose-rate radiation effects on the physical heights of children staying in apartments with 60Co-contaminated steel construction. MATERIALS AND METHODS: Children who once resided in radiocontaminated apartments since early 1983 were examined for height and body weight status from age 1 month to 18 years and before they moved out of the apartments. The physical heights and body weights of 21 898 age- and sex-matched non-exposed children from a nationwide school surveillance in 1997-98 were taken as controls. The physical height data were shown as height percentiles (HP) compared with reference children and age-specific relative height differences (RHD). RESULTS: HP and RHD in 48 exposed boys and 37 girls were analysed using generalized estimating equations (GEE), which accounted for multiple measurements and correlation between these measurements in the same individuals during this period. After adjusting for effects from parental heights and body mass index (BMI), clear dose-related decreases in HP and RHD were observed in the exposed boys with a cumulative exposure > 60 mSv. CONCLUSIONS: Prolonged low dose-rate y-radiation exposure was associated with adverse effects on the physical heights of growing boys, but were less apparent in the exposed girls.

Adolescent↗
PubMed2001

Dynamics of changes in micronucleus frequencies in subjects post cessation of chronic low-dose radiation exposure.

To assess DNA damage remaining in peripheral lymphocytes, 48 individuals were evaluated twice for lymphocyte micronucleus frequencies by the cytokinesis-blocking cytochalasin B (CBMN) analysis post relocation from radio-contaminated apartments after various periods of time. The frequencies of CBMN at the first evaluation were significantly higher than those at the second examination (Chang et al., 1999c). These individuals were categorized into three groups: those with cumulative exposure of >300 mSv (defined as high exposure, HDose), those with 100-300 mSv (MDose) and those with <100 mSv (LDose). Using the Poisson mixed-effect model (Little et al., 1996), the estimated mean CBMN frequencies ( per thousand) for individuals in HDose, MDose and LDose exposure categories when they had only recently relocated were 21.8, 17.6 and 15.4, respectively. The estimated mean duration post relocation for the CBMN frequencies of these individuals to reduce to 10.2, the second CBMN frequency, on average, was 47.5, 37.2 and 28.3 months in the three exposure groups, respectively. The rates of change in CBMN frequencies were shown to be significantly higher in the HDose group than in the MDose and LDose groups. The results suggested a characteristic dose-dependent decline in the CBMN frequencies in the exposed population post cessation of chronic low-dose ionizing radiation exposure.

Adolescent↗
PubMed2001

A study of the display pixel-based focusing method in ultrasound imaging.

This paper presents a new beamforming technique, in which ultrasound waves are focused at the display pixels on the Cartesian coordinates, rather than sampling points located on the uniformly-separated scanlines on either the polar or Cartesian coordinates. Consequently, this method does not require a digital scan converter (DSC) and therefore completely eliminates the distortions due to the DSC. A new imaging system based on the proposed method is also presented, which is advantageous over conventional systems in hardware complexity, especially when high-density imaging is required. The new method can also be used effectively to achieve high frame rates for real-time 3D imaging and cardiac applications. To verify the proposed method, we modified a commercial ultrasound scanner and performed experiments with a 3.5 MHz convex array and a 7.5 MHz linear array. The experimental results with in vivo and in vitro data show that the proposed technique provides much smoother and finer images than the conventional dynamic focusing methods.

Humans↗
PubMed2001

Lenticular opacities in populations exposed to chronic low-dose-rate gamma radiation from radiocontaminated buildings in Taiwan.

Chen, W-L., Hwang, J-S., Hu, T-H., Chen, M-S. and Chang, W. P. Lenticular Opacities in Populations Exposed to Chronic Low-Dose-Rate Gamma Radiation from Radiocontaminated Buildings in Taiwan. Radiat. Res. 156, 71-77 (2001). Epidemiological and experimental studies have revealed the cataractogenic potential of large acute doses of radiation. However, studies on the dose-response effect and the incidence of lenticular changes after exposure to chronic low doses of radiation have seldom been conducted. To evaluate quantitatively the lenticular changes in a population exposed to chronic low-dose-rate gamma radiation in their daily living or school environment in steel buildings contaminated with (60)Co in Taiwan, a total of 114 exposed individuals participated in a thorough ophthalmological examination in 1998. The lenticular opacities were evaluated by slit-lamp biomicroscopy after full pupil dilatation and were scored by the Lens Opacities Classification System III (LOCS III) and a modified subclinical minor lenticular focal defects system. These individuals were further divided into those less than 20 years old, those between 20 and 40 years old, and those more than 40 years old to evaluate the effects of age. The cumulative doses were assessed for each individual using the Taiwan Cumulative Dose (TCD) estimation system. A significant dose-dependent increase in the numbers of focal lens defects in those less than 20 years old was demonstrated, while less significant changes were observed in the other two age groups or by the LOCS III scoring. Results suggested that chronic low-dose-rate irradiation might induce minor lenticular changes, especially in lenses of young subjects. The delayed clinical changes in these young exposed subjects warrants further long-term follow-up.

Adolescent↗
PubMed2001

Case report of a granular cell tumour in the nasal septum of a child.

A six-year-old child with a nasal septal polyp presents with pain and nasal discharge. The diagnosis of a granular cell tumour was made histologically on excision of the polyp. This interesting case of an uncommon lesion presenting in a relatively rare paediatric age group is, as far as we know, the first report of a granular cell tumour involving the nasal septum.

Child↗