• The Korean Journal of Physiology and Pharmacology
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• v.18 no.5
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• pp.411-418
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• 2014

Vascular remodelling is an adaptive mechanism, which counteracts pressure changes in blood circulation. Nicotine content in cigarette increases the risk of hypertension. The exact relationship between nicotine and vascular remodelling still remain unknown. Current study was aimed to determine the effect of clinically relevant dosage of nicotine (equivalent to light smoker) on aortic reactivity, oxidative stress markers and histomorphological changes. Twelve age-matched male Sprague-Dawley rats were randomly divided into two groups, i.e.: normal saline as control or 0.6 mg/kg nicotine for 28 days (i.p., n=6 per group). On day-29, the rats were sacrificed and the thoracic aorta was dissected immediately for further studies. Mean arterial pressure (MAP) and pulse pressure (PP) of nicotine-treated vs. control were significantly increased (p<0.05). Nicotine-treated group showed significant (p<0.05) increase tunica media thickness, and decrease in lumen diameter, suggesting vascular remodelling which lead to prior hypertension state. The phenylephrine (PE)-induced contractile response in nicotine group was significantly higher than control group ($ED_{50}=1.44{\times}10^5M$ vs. $4.9{\times}10^6M$) (p<0.05~0.001). However, nicotine-treated rat showed significantly lower endothelium-dependent relaxation response to acetylcholine (ACh) than in control group ($ED_{50}=6.17{\times}10^7M$ vs. $2.82{\times}10^7M$) (p<0.05), indicating loss of primary vascular function. Malondialdehyde (MDA), a lipid peroxidation marker was significantly higher in nicotine group. Superoxide dismutase (SOD) enzymatic activity and glutathione (GSH) were all reduced in nicotine group (p<0.05) vs. control, suggesting nicotine induces oxidative imbalance. In short, chronic nicotine administration impaired aortic reactivity, probably via redox imbalance and vascular remodelling mechanism.

• Tribology and Lubricants
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• v.35 no.1
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• pp.44-51
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• 2019

The paper presents the rotordynamic performance measurements and model predictions of a fuel cell electric vehicle (FCEV) air compressor supported on gas foil bearings (GFBs). The rotor has an impeller on one end and a thrust runner on the other end. The front (impeller side) and rear (thrust side) gas foil journal bearings (GFJBs) are located between the impeller and thrust runner to support the radial loads, and a pair of gas foil thrust bearings are located on both sides of the thrust runner to support the axial loads. The test GFJBs have a partial arc shim foil installed between the top foil and bump strip layers to enhance hydrodynamic pressure generation. During the rotordynamic performance tests, two sets of orthogonally installed eddy-current displacement sensors measure the rotor radial motions at the rotor impeller and thrust ends. A series of speed-up and coast-down tests to 100k rpm demonstrates the dominant synchronous (1X) rotor responses to imbalance masses without noticeable subsynchronous motions, which indicates a rotordynamically stable rotor-GFB system. Finite element analysis of the rotor determines the rotor free-free (bending) natural modes and frequencies well beyond the maximum rotating frequency. The predicted damped natural frequencies and damping ratios of the rotor-GFB system reveal rotordynamic stability over the speeds of interest. The imbalance response predictions show that the predicted critical speeds and rotor amplitudes strongly agree with the test measurements, thus validating the developed rotordynamic model.

• Research in Vestibular Science
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• v.17 no.4
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• pp.152-159
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• 2018

Objectives: The Korean Dizziness Handicap Inventory (KDHI), which includes 25 patient-reported items, has been used to assess self-reported dizziness in Korean patients with Parkinson disease (PD). Nevertheless, few studies have examined the KDHI based on item-response theory within this population. The aim of our study was to address the feasibility and clinimetric properties of the KDHI instrument using polytomous Rasch measurement analysis. Methods: The unidimensionality, scale targeting, separation reliability, item difficulty (severity), and response category utility of the KDHI were statistically assessed based on the Andrich rating scale model. The utilities of the orderedresponse categories of the 3-point Likert scale were analyzed with reference to the probability curves of the response categories. The separation reliability of the KDHI was assessed based on person separation reliability (PSR), which is used to measure the capacity to discriminate among groups of patients with different levels of balance deficits. Results: Principal component analyses of residuals revealed that the KDHI had unidimensionality. The KHDI had satisfactory PSR and there were no disordered thresholds in the 3-point rating scale. However, the KDHI showed several issues for inappropriate scale targeting and misfit items (items 1 and 2) for Rasch model. Conclusions: The KDHI provide unidimensional measures of imbalance symptoms in patients with PD with adequate separation reliability. There was no statistical evidence of disorder in polytomous rating scales. The Rasch analysis results suggest that the KDHI is a reliable scale for measuring the imbalance symptoms in PD patients, and identified parts for possible amendments in order to further improve the linear metric scale.

• Journal of Microbiology and Biotechnology
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• v.32 no.11
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• pp.1406-1415
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• 2022

The formation of macrophage foam cells stimulated by oxidized low-density lipoprotein (ox-LDL) is deemed an important cause of atherosclerosis. Transcription factor Yin Yang 1 (YY1), which is a universally expressed multifunctional protein, is closely related to cell metabolism disorders such as lipid metabolism, sugar metabolism, and bile acid metabolism. However, whether YY1 is involved in macrophage inflammation and lipid accumulation still remains unknown. After mouse macrophage cell line RAW264.7 cells were induced by ox-LDL, YY1 and proprotein convertase subtilisin/kexin type 9 (PCSK9) expressions were found to be increased while low-density lipoprotein receptor (LDLR) expression was lowly expressed. Subsequently, through reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blot analysis, Oil Red O staining and cholesterol quantification, it turned out that silencing of YY1 attenuated the inflammatory response and lipid accumulation in RAW264.7 cells caused by ox-LDL. Moreover, results from the JASPAR database, chromatin immunoprecipitation (ChIP) assay, luciferase reporter assay and Western blot analysis suggested that YY1 activated PCSK9 by binding to PCSK9 promoter and modulated the expression of LDLR in the downstream of PCSK9. In addition, the results of functional experiments demonstrated that the inhibitory effects of YY1 interference on ox-LDL-mediated macrophage inflammation and lipid accumulation were reversed by PCSK9 overexpression. To sum up, YY1 depletion inhibited its activation of PCSK9, thereby reducing cellular inflammatory response, cholesterol homeostasis imbalance, and lipid accumulation caused by ox-LDL.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.3
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• pp.345-351
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• 2014

Purpose: The accommodative response and the near horizontal phoria were examined with additional spherical power to analyze the stimulus and response AC/A ratios that suggest reference data for the binocular vision. Methods: The open-field autorefractometer (Nvision-K 5001, Shin nippon) and modified thorington method (MIM card; Muscle Imbalance Measure card, Bernell) at 40 cm were utilized to measure the accommodative response and the near horizontal phoria for 81 persons ($20.89{\pm}1.92$ years old) with additional spherical power. The stimulus and the response AC/A ratios were calculated by gradient AC/A method. Results: The exophoria group showed the highest accommodative response ($1.92{\pm}0.26D$) at 40 cm, followed by orthophoria group and esophoria group($1.72{\pm}0.26D$ and $1.62{\pm}0.42D$, respectively) Meanwhile, the esophoria group showed the biggest ocular deviation for the near ($23.24{\Delta}$) followed by the orthophoria group and exophoria group ($19.76{\Delta}$ and $15.14{\Delta}$, respectively). The biggest difference of the stimulus and the response AC/A ratios was $1.72{\Delta}$ for the exophoria group with -2.00 D, while the one was $3.43{\Delta}$ for the esophoria group with +1.00 D. There was a significant difference between AC/A ratios for the exophoria group with -2.00 D, -1.00 D and the esophoria group with +3.00 D, +2.00D, +1.00D and -1.00D. Conclusions: The difference between stimulus and response AC/A was greater when increased minus spherical power for the exophoria group, while it was greater when increased plus spherical power for the esophoria group. Furthermore, the difference for the esophoria group was a greater than the one for the exophoria group.

• Food Science of Animal Resources
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• v.43 no.6
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• pp.1044-1054
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• 2023

Growing evidence indicates a crucial role of the gut microbiota in physiological functions. Gut-brain axis imbalance has also been associated with neuropsychiatric and neurodegenerative disorders. Studies have suggested that probiotics regulate the stress response and alleviate mood-related symptoms. In this study, we investigated the effects of the probiotic Lacticaseibacillus rhamnosus IDCC3201 (L3201) on the behavioral response and fecal metabolite content in an unpredictable chronic mild stress (UCMS) mouse model. Our study shows that chronic stress in mice for three weeks resulted in significant changes in behavior, including lower locomotor activity, higher levels of anxiety, and depressive-like symptoms, compared to the control group. Metabolomic analysis demonstrated that disrupted fecal metabolites associated with aminoacyl-tRNA biosynthesis and valine, leucine, and isoleucine biosynthesis by UCMS were restored with the administration of L3201. Oral administration of the L3201 ameliorated the observed changes and improved the behavioral alterations along with fecal metabolites, suggesting that probiotics play a neuroprotective role.

• The Korean Journal of Physiology and Pharmacology
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• v.24 no.2
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• pp.137-147
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• 2020

Ulcerative colitis (UC) is associated with intestinal immune imbalance and inflammatory response. Because dehydrolovastatin (DLVT), a derivative of lovastatin, has been recently shown to inhibit inflammation and relieve immune arthritis induced by chemical stimuli, we studied its effect and possible mechanism on UC induced by dextran sulfate sodium. The BALB/c mice were classified into six groups: normal control group, model group, DLVT high dose group, DLVT low dose group, salazosulfapyridine (SASP) group and lovastatin (LVT) group. The disease activity indices of UC and pathological changes were investigated. The myeloperoxidase (MPO) activity in colon tissue and inflammatory factors such as IL-6, IL-10, IL-17, and TNF-α in the serum were analyzed by ELISA, while the expression of NF-κB p65 protein in colon tissue was detected by immunohistochemistry and western blot. DLVT relieved the disease activity indices and pathological damage of the UC mice. Furthermore, DLVT significantly decreased MPO activity and improved the imbalance of inflammatory cytokines through inhibiting the expression of NF-κB p65. Meanwhile, the positive drug of SASP has a similar effect to DLVT, but the effect of DLVT in both decreasing IL-17, TNF-α, and increasing IL-10 was significantly stronger than that of SASP. These results suggest that DLVT may ameliorates the symptoms of UC.

• The Korean Journal of Applied Statistics
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• v.23 no.3
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• pp.457-469
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• 2010

The government real estate policy has repeatedly relaxed and reinforced controls under the mutually contradictory targets. Switching over the supporting policy after the IMF crisis to the regulating policy from 2003, the government housing policy began to generate ill effects due to various regulations. This stud carefully investigates and statistically tests the transmissions of variations in the housing prices between the metropolitan areas in the early stage of the preceding administration, under the effect of the supporting scheme, and those in the late stage, under the effect of the restricting scheme. The distinctive feature between the two periods is found to be much simplified interrelationships of the price variations in the latter period. Consolidated leading role of capital sphere, by concentrated economic strength, suggest the obvious imbalance between variations in the metropolis housing prices.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.111-117
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• 2004

Hepatic microcirculatory failure is a major component of reperfusion injury in the liver. Recent data provided some evidence that endothelium-derived vasoconstrictors and vasodilators may be functionally important to the control of the total hepatic blood flow under these conditions of circulatory failure. Since Kupffer cells provide signals that regulate the hepatic response in ischemia/reperfusion (I/R), the aim of this study was to investigate the role of Kupffer cells in the I/R-induced imbalance of vasoregulatory gene expression. Rats were subjected to 60 min hepatic ischemia, followed by 5 h of reperfusion. The Kupffer cells were inactivated by gadolinium chloride ($GdCl_3$, 7.5 mg/kg body weight, intravenously) 1 day prior to ischemia. Liver samples were obtained 5 hrs after reperfusion for RT-PCR analysis of the mRNA for genes of interest: endothelin-1 (ET-1), its receptors $ET_A and ET_B$, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1). ET-1 mRNA expression was increased by I/R. mRNA levels for $ET_A$ receptors showed no change, whereas $ET_B$ receptor transcripts increased in the I/R group. The increases in ET-1 and $ET_B$ mRNA were not prevented by the $GdCI_3$ pretreatment. The mRNA levels for iNOS and eNOS significantly increased within the I/R group with no significant difference between the I/R group and the $GdCl_3$-treated I/R group. HO-1 mRNA expression significantly increased in the I/R group and this increase was attenuated by $GdCI_3$. In conclusion, we have demonstrated that an imbalance in hepatic vasoregulatory gene expression occurs during I/R. Our findings suggest that the activation of Kupffer cells is not required for I/R-induced hepatic microvascular dysfunction.