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Biomedical subjects

Y Kim

Publications and source records attributed to Y Kim.

At least 19 recordsLinked to original sources

Electrochemical detection of pathogen infection using cell chip.

The immobilized cell using self-assembled synthetic oligopeptide was applied to the electrochemical detection of pathogen infection. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for the immobilization of HeLa cell on gold (Au) substrate. Layer formation and immobilization of the cell were investigated with surface plasmon resonance (SPR) and electrochemical impedance spectroscopy (EIS). Experimental results showed that the thin film of cysteine-terminated synthetic oligopeptide was successfully fabricated and it could be applied for the immobilization of HeLa cells. The adhered living cell was exposed to E. coli O157:H7, which induced the change of SPR angle and electrochemical impedance signal. The proposed cell immobilization method using self-assembly technique can be applied to construct the cell microarray for on-site pathogen monitoring.

Carcinoma↗

Changes in the levels of interferon-gamma and transforming growth factor-beta influence bronchial stenosis during the treatment of endobronchial tuberculosis.

BACKGROUND: Endobronchial tuberculosis (EBTB) has been shown to frequently complicate bronchial stenosis, a condition which can induce dyspnea as a result of airway obstruction, and is also frequently misdiagnosed as either bronchial asthma or lung cancer. OBJECTIVES: This study attempted to determine whether there was a correlation between interferon-gamma (IFN-gamma) and transforming growth factor-beta (TGF-beta) levels in the serum and bronchial washing fluid (BWF), and the results of the treatment of EBTB patients. METHODS: Thirty patients, all of whom were diagnosed as EBTB, were enrolled, as were 10 healthy control subjects. IFN-gamma and TGF-beta levels were measured by the ELISA method in the serum and BWF of these 30 EBTB patients before and after treatment. The EBTB patients were divided into two groups: those who exhibited bronchial stenosis after treatment and those who did not. Chest computed tomography (CT) and pulmonary function test (PFT) were performed in 16 and 25 patients, respectively, at initial bronchoscopy. RESULTS: IFN-gamma and TGF-beta levels in the BWF of the EBTB patients were elevated compared to the controls (p < 0.05). After 2 months of treatment, 13 of the 30 EBTB patients exhibited bronchial fibrostenosis and the other 17 cases had recovered without sequelae. In the bronchial stenosis group, the initial serum TGF-beta levels were lower than in the patients without bronchial stenosis (p < 0.05). Moreover, the levels of serum TGF-beta after treatment were shown to have decreased more than in the patients without bronchial stenosis (p < 0.05). On chest CT findings of 16 EBTB patients, bronchial narrowing was suspected except in 2 cases (1 edematous-hyperemic type, 1 actively caseating type of segmental bronchus). The common features of PFT in EBTB at the initial diagnosis were a restrictive pattern and normal ventilatory function. CONCLUSIONS: Elevated IFN-gamma and TGF-beta levels in the BWF of the EBTB patients may be related to EBTB pathogenesis. Lowered initial serum TGF-beta levels as well as the observed changes in the levels of TGF-beta in the serum after treatment have been implicated in bronchial fibrostenosis during the course of the disease.

Adult↗

Effects of a combined alendronate and calcitriol agent (Maxmarvil) on bone metabolism in Korean postmenopausal women: a multicenter, double-blind, randomized, placebo-controlled study.

INTRODUCTION: A randomized, double-blind, prospective, 24-week clinical trial was performed to evaluate the effects of a combinative agent, Maxmarvil, of calcitriol (0.5 mug) and alendronate (5 mg) on bone metabolism in postmenopausal women. METHODS: A total of 217 postmenopausal women with osteoporosis were enrolled; 199 patients were randomly assigned to one of two treatment groups (Maxmarvil group or alfacalcidol group). None of the patients were vitamin-D-deficient, as assessed by serum 25-hydroxyvitamin D (25(OH)D), nor had they received any drugs affecting bone metabolism before enrollment. Bone mineral densities (BMD) of L1-L4 and the femur were measured by dual-energy X-ray absorptiometry (DXA) at the initial assessment and after 6 months of treatment. Serum biochemical assays, including serum calcium, 24-h urinary calcium excretion, and bone turnover markers (both bone-specific alkaline phosphatase [bsALP] and urine N-telopeptide [NTx]), were performed at the baseline and after 3 and 6 months of treatment. RESULTS: In the Maxmarvil group, the BMD of the lumbar spine increased up to 2.42+/-0.5% from the baseline after 6 months (p<0.05). On the other hand, the change in BMD in the alfacalcidol group was 0.28+/-0.5% after 6 months. There was no significant difference in femoral BMD between the two groups. The levels of bsALP and NTx were significantly lower in the Maxmarvil group than in the alfacalcidol group (-22.04+/-3.9% vs. -11.42+/-2.8% [p<0.05] and -25.46+/-5.2% vs. 1.24+/-6.2% [p<0.001], respectively). Interestingly, there was a significantly smaller amount of 24-h urinary calcium in the Maxmarvil group (p<0.05). CONCLUSIONS: Our study demonstrates that a combination of calcitriol and alendronate is quite effective in preventing bone loss, with the advantage of lesser hypercalciuric effect of calcitriol in the postmenopausal osteoporotic women.

Alendronate↗

Characteristics of CADASIL in Korea: a novel cysteine-sparing Notch3 mutation.

OBJECTIVE: To elucidate the phenotype, genotype, and MRI findings of Korean patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and mutation carriers. METHODS: The authors studied 40 members of nine unrelated Korean CADASIL families. After genetic analysis of Notch3, clinical and MRI findings were correlated in 27 mutation carriers. RESULT: Notch3 mutation sites were C174R (one family, n = 3), R133C (one family, n = 3), R587C (one family, n = 1), R544C (two families, n = 5), and R75P (four families, n = 15). The clinical features were typical of CADASIL, but the frequency of migraine in the Korean population appears low. MRI abnormalities were found in 54% of the mutant carriers, the most common being white matter hyperintensities. The prevalence of lacunes and microbleeds increased with patient age. Anterior temporal areas were less often involved in subjects with R75P mutations than in those where mutations occurred in other sites (p = 0.02). Gradient echo imaging identified microbleedings in 33% of mutation carriers (64% of those with abnormal MRI), whereas diffusion-weighted MRI showed abnormal findings in only one patient. Neurologic disability was related to the number of lacunar infarcts and the lesion volume of white matter hyperintensities (p < 0.001) whereas MMSE score was related to the number of lacunar infarcts (p < 0.005). CONCLUSIONS: Although Korean cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) mutation carriers show similar clinical and MRI findings, these abnormalities appear less frequently than in other populations. Relatively frequent microbleedings on gradient echo imaging suggest that treatment should be individualized according to MRI findings. The novel mutation of R75P, not involving a cysteine residue, is related to less frequent involvement of the anterior temporal area, thus broadening the spectrum of CADASIL.

Adult↗

Burden of disease attributable to obesity and overweight in Korea.

OBJECTIVE: To estimate the burden of disease attributable to overweight and obesity using disability-adjusted life-year (DALY) in Korea. RESEARCH METHODS: Firstly, overweight and obesity-related diseases and their relative risk (RR) were selected by the systematic review. Secondly, population-attributable fractions (PAFs) were computed by using the formula including RR and the prevalence of exposure (Pe) of overweight and obesity. Thirdly, DALYs of overweight and obesity-related diseases in Korea were estimated. Finally, the attributable burden (AB) of diseases due to overweight and obesity was calculated as the sum of the products from multiplying DALYs of overweight and obesity-related diseases by their PAFs. RESULTS: The disease burden attributable to overweight was 827.1 person years (PYs) overall, 732.6 for men, 922.9 for women per 100,000 persons. The disease burden attributable to obesity was 260.0 PYs overall, 144.2 for men, 377.3 for women. Diabetes attributable to overweight and obesity accounts for highest burden among other diseases in both genders. The disease burden attributable to overweight was 3.2 times higher than that attributable to obesity. CONCLUSION: Most proportion of disease burden attributable to high body mass index (BMI) occurred among those with only moderately raised levels such as overweight, not the extremes such as obesity. It suggests that population-based, public health intervention rather than high-risk group-focused strategies are more effective to reduce the burden of disease attributable to overweight and obesity in Korea.

Adult↗

Amyloid-producing odontogenic tumour (calcifying epithelial odontogenic tumour) in the mandible of a Bengal tiger (Panthera tigris tigris).

A 13-year-old male tiger (Panthera tigris tigris) had a marked mandibular swelling noticed 12 months earlier and associated with progressive anorexia and weight loss. Radiological and post-mortem examination revealed a mass (13x15 cm) which was firm and poorly defined, with destruction of the adjacent bone tissue. Histologically, the mass was poorly demarcated, with infiltrative growth, and composed of nests, cords and islands of epithelial cells with characteristic basal cell features. Also observed were extensive squamous metaplasia, ghost cells, stellate reticulum, and fibroblastic connective tissue stroma containing inflammatory cells. A prominent feature of this tumour consisted of abundant nodular deposits of congophilic amyloid-like material with partial mineralization (Liesegang rings). Immunohistochemically, the neoplastic cells and the amyloid-like material were positive for pancytokeratin and negative for vimentin. The findings supported the diagnosis of an amyloid-producing odontogenic tumour (APOT), also known as calcifying epithelial odontogenic tumour in man and animals.

Ameloblastoma↗

Expression of cell-cycle regulator CDK2-associating protein 1 (p12CDK2AP1) in transgenic mice induces testicular and ovarian atrophy in vivo.

The novel cell-cycle regulator p12(CDK2AP1) (p12) gene encodes a cyclin-dependent kinase 2 (CDK2) partner that participates in cell-cycle regulation, apoptosis, and proliferation. CDK2 has been implicated in maintenance of gonadal homeostasis, as knockout mice display reproductive abnormalities. To investigate the role of p12 in homeostasis of gonadal tissues in vivo, we generated a transgenic mouse model driven by the human keratin 14 promoter, reported to target transgene expression to gonadal tissues and also stratified epithelia. Overexpression of the transgene was associated with a gonadal atrophy phenotype in mice of both sexes, yet fertility was not impaired. Histological evaluation of testes showed seminiferous tubule degeneration and decreased tubule diameter. Female transgenic mice had small ovaries, with a higher number of atretic follicles/mm(2) as compared to control nontransgenic mice. Also observed was increased germ cell apoptosis in both sexes (TUNEL). These results suggest that overexpression of p12 leads to testicular and ovarian abnormalities, a phenotype closely related to that of cdk2-/- mice. In combination, these observations suggest that the p12/CDK2 signaling pathways are carefully orchestrated to maintain proper gonadal tissue homeostasis. We suggest that the mechanisms of this regulation may be through p12-mediated altered expression of gonadal-specific genes and apoptotic pathways.

Animals↗

N-acetylphytosphingosine-induced apoptosis of Jurkat cells is mediated by the conformational change in Bak.

N-acetylphytosphingosine (NAPS), a sphingolipid derivative, is one of the well-known signal molecules that mediates various cellular functions, including cell growth, differentiation, and apoptosis. In this study, we demonstrated that NAPS induces apoptosis of Jurkat cells by activating Bak, but not Bax, which are both members of a proapoptotic subfamily of the Bcl-2 proteins. NAPS activated caspase-8 in a FADD-independent manner, but the lack of caspase-8 did not suppress the activation of caspase-3 and -9 and cell death, indicating that caspase-8 activation does not play an important role in NAPS-induced cell death. The overexpression of Bcl-xL, an anti-apoptotic protein, completely inhibited the activation of the caspases and apoptosis, assuming that NAPS-induced apoptosis was initiated by the mitochondria. The expression levels of pro- and anti-apoptotic Bcl-2 family members were not changed by the NAPS treatment. However, Bad was translocated from the cytosol into the mitochondria, where it bound to Bcl-xL, and Bak was dissociated from Bcl-xL and conformationally changed. Taken together, these findings indicate that NAPS induced apoptosis of Jurkat cells in a mitochondria-dependent manner that was controlled by the translocation of Bad and the conformational change in Bak.

Adaptor Proteins, Signal Transducing↗

Intrathecal implants of microencapsulated xenogenic chromaffin cells provide a long-term source of analgesic substances.

Adrenal medullary chromaffin cells secrete several neuroactive substances including catecholamines and opioid peptides that produce analgesic effects in the central nervous system. This study was designed to investigate whether intrathecal microencapsulated chromaffin cells could release analgesic materials producing antiallodynic effects on the chronic neuropathic pain in rats induced by chronic constriction injury (CCI) of the sciatic nerve. Prior to intrathecal implantation, chromaffin cells were encapsulated with alginate and poly-L-lysine to protect them from the host immune system. Behavior tests were performed before CCI, 1 week later, and at 4, 7, 14, 21, 28 days postimplantation. At the end of study, we performed cerebrospinal fluid (CSF) collection and implant retrieval. We observed that intrathecal implantation of encapsulated xenogenic chromaffin cells reduced the mechanical and cold allodynia in a model of neuropathic pain. CSF levels of catecholamines and metenkephalin in the rats that received implants were higher than the controls. In addition, we observed chronic survival of implants. These results suggested that intrathecal microencapsulated chromaffin cells may represent a new approach to chronic neuropathic pain management.

Absorbable Implants↗

Effects of Lactobacillus strains on cancer cell proliferation and oxidative stress in vitro.

AIMS: The objective of this study was to assess in vitro, whether heat-killed (HK) lactic acid bacteria cells and fractionations of HK cells could suppress the viability of human cancer cells and inhibit the cytotoxicity associated with oxidative stress. METHODS AND RESULTS: Among the strains, the HK cells of Lactobacillus acidophilus 606 and Lactobacillus casei ATCC 393 exhibited the most profound inhibitory activity in all of the tested cell lines. HK cells of L. acidophilus 606 were determined to be less toxic to healthy human embryo fibroblasts (hEF cells) than were HK cells of L. casei ATCC 393. The soluble polysaccharides from L. acidophilus 606 evidenced the most effective anticancer activity, but inhibited hEF cell growth by only 20%. The soluble polysaccharides from L. acidophilus 606 were partly observed to induce apoptosis in the HT-29 cells by DNA fragmentation and propidium iodine staining. Both the HK cells of L. acidophilus 606 and the soluble polysaccharide components of this strain also exhibited potent antioxidative activity. CONCLUSIONS: Our findings suggest that the soluble polysaccharide fraction from L. acidophilus 606 may constitute a novel anticancer agent, which manifests a high degree of selectivity for human cancer cells and antioxidative agent in the food industry. SIGNIFICANCE AND IMPACT OF THE STUDY: These soluble polysaccharide components from Lactobacillus may be applied to various foods, and used as adjuncts for cancer therapy and prevention.

Antineoplastic Agents↗

Inhibitory effects of Lactobacillus acidophilus lysates on the cytotoxic activity of shiga-like toxin 2 produced from Escherichia coli O157:H7.

AIMS: The purpose of this study was to characterize the degree to which four cell lysates obtained from Lactobacillus acidophilus strains affected the cytotoxic activity of Escherichia coli O157:H7 in vitro and in vivo. METHODS AND RESULTS: In a cytotoxic inhibition test that used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and toxin-binding ELISA assays, the activity of shiga-like toxin 2 (Stx-2) was inhibited profoundly by the cell lysates (10 mg ml(-1)) from two strains of L. acidophilus A4 and 30SC (>85% of survival rates compared with the control) among the five strains tested. In particular, a significant decline in the virulence level of E. coli O157:H7, under the presence of the cell lysates of L. acidophilus A4, was observed by killing assay of Caenorhabditis elegans in vivo model. CONCLUSIONS: According to our results, L. acidophilus strains might be capable of attenuating the virulence of Stx-2 produced from E. coli O157:H7. SIGNIFICANCE AND IMPACT OF THE STUDY: The cell lysates of L. acidophilus can be applied to a variety of foods, and can be used as adjuncts for the inhibition of Stx-2-mediated cytotoxicity.

Animals↗

Mental health service requirements in a Japanese medical centre emergency department.

BACKGROUND: A significant number of emergency department (ED) patients in Japan may be affected by mental health problems leading to attempted suicide. This retrospective descriptive study aimed to explore mental health service needs in a Japanese medical centre ED. METHODS: Data on all inpatients were collected within 24 h of admission to the ED of a medical centre in Tokyo from 1st February 2004 to the 31st of January 2005. RESULTS: A total of 14.4% (95% CI 13.0 to 16.0) of ED visits required psychiatric services and 23.4% (95% CI 21.7 to 25.3) of inpatients had experienced psychologically traumatic events. CONCLUSIONS: Approximately 38% (95% CI 35.8 to 39.9) of patients presenting to an ED could be affected by mental health problems.

Adolescent↗

Knowledge-based control and case-based diagnosis based upon empirical knowledge and fuzzy logic for the SBR plant.

Because biological wastewater treatment plants (WWTPs) involve a long time-delay and various disturbances, in general, skilled operators manually control the plant based on empirical knowledge. And operators usually diagnose the plant using similar cases experienced in the past. For the effective management of the plant, system automation has to be accomplished based upon operating recipes. This paper introduces automatic control and diagnosis based upon the operator's knowledge. Fuzzy logic was employed to design this knowledge-based controller because fuzzy logic can convert the linguistic information to rules. The controller can manage the influent and external carbon in considering the loading rate. The input of the controller is not the loading rate but the dissolved oxygen (DO) lag-time, which has a strong relation to the loading rate. This approach can replace an expensive sensor, which measures the loading rate and ammonia concentration in the reactor, with a cheaper DO sensor. The proposed controller can assure optimal operation and prevent the over-feeding problem. Case-based diagnosis was achieved by the analysis of profile patterns collected from the past. A new test profile was diagnosed by comparing it with template patterns containing normal and abnormal cases. The proposed control and diagnostic system will guarantee the effective and stable operation of WWTPs.

Ammonia↗

Injection of skeletal muscle-derived cells into the penis improves erectile function.

We investigated the effect of intrapenile injection of muscle-derived cells (MDC) on the erectile function in rats with bilateral cavernous nerve injury. Rat MDC were harvested and transduced with a retrovirus expressing the lacZ gene. Hanks' balanced salt solution (HBSS) (20 microl) or MDC (1 x 10(6) cells/side) were injected in each corpora cavernosa immediately before bilateral cavernous nerve transection. Intracavernous pressures (ICP) were measured 2 or 4 weeks after surgery with electrical stimulation of the pelvic nerves. Mean maximal ICP of sham group was significantly lower than that of control group both at 2 and 4 weeks after surgery. When MDC were injected into the penis, ICP improved over the sham-injected group at both 2 and 4 weeks after surgery. Percent area of PGP 9.5 staining was significantly greater in MDC-injected penis than in sham-injected at 2 and 4 weeks. Penile MDC injection can facilitate recovery of injured penile innervation and improve erectile function.

Animals↗

Radiofrequency thermal ablation of hepatic tumors: pitfalls and challenges.

Image-guided radiofrequency (RF) thermal ablation has been accepted as a promising interventional technique to control unresectable hepatic tumors. One important key to maximize the efficacy of RF ablation is to adhere to the therapeutic guidelines and to avoid preventable pitfalls. There are also several challenges obstructing successful ablation: poor approach path; small sonic window during multiple overlapping ablations; incomplete ablation due to the heat sink effect; subcapsular mass (too exophytic or the mass is adjacent to the gastrointestinal tract); focal residual tumors; too isoechoic or small masses; and mistargeting to adjacent another lesion. Knowledge of these challenges and pitfalls in RF ablation is helpful for a successful ablation.

Catheter Ablation↗

Multiport N x N multimode air-clad holey fiber coupler for high-power combiner and splitter.

We report 2 x 2 and 4 x 4 multimode air-clad holey fiber couplers fabricated by a novel fusion and tapering technique. The devices showed excellent port-to-port coupling uniformity over a wide spectral range of 800-1650 nm. The 4 x 4 coupler showed a low insertion loss of 9.9 dB and excess loss of 3.9 dB at 1310 nm. Because of its unique air cladding and the high numerical aperture of the holey fiber structure, the device showed strong potential in high-power applications.

Journal Article↗