• 한국수정란이식학회지
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• 제28권2호
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• pp.157-162
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• 2013

Methoxychlor (MXC) was developed to be a replacement for the banned pesticide DDT. HPTE [2,2-bis (p-hydroxyphenyl)-1,1,1-trichloroethane], which is an in vivo metabolite of MXC, has strong oestrogenic and anti-androgenic effects. MXC and HPTE are thought to produce potentially adverse effects by acting through oestrogen and androgen receptors. Of the two, HPTE binds to sex-steroid receptors with greater affinity, and it inhibits testosterone biosynthesis in Leydig cells by inhibiting cholesterol side-chain cleavage enzyme activity and cholesterol utilisation. In a previous study, MXC was shown to induce Leydig cell apoptosis by decreasing testosterone concentrations. I focused on the effects of MXC on male mice that resulted from interactions with sex-steroid hormone receptors. Sex-steroid hormones affect other organs including the kidney and liver. Accordingly, I hypothesised that MXC can act through sex-steroid receptors to produce adverse effects on the testis, kidney and liver, and I designed our experiments to confirm the different effects of MXC exposure on the male reproductive system, kidney and liver. In these experiments, I used pre-pubescent ICR mice; the puberty period in ICR mice is from postnatal day (PND) 45 to PND60. I treated the experimental group with 0, 100, 200, 400 mg MXC/kg b.w. delivered by an intra-peritoneal injection with sesame oil used as vehicle for 4 weeks. At the end of the experiment, the mice were sacrificed under anaesthesia. The testes and accessory reproductive organs were collected, weighed and prepared for histological investigation. I performed a chemiluminescence immune assay to observe the serum levels of testosterone, LH and FSH. Blood biochemical determination was also performed to check for other effects. There were no significant differences in our histological observations or relative organ weights. Serum testosterone levels were decreased in a dose-dependent manner; a greater dose resulted in the production of less testosterone. Compared to the control group, testosterone concentrations differed in the 200 and 400 mg/kg dosage groups. In conclusion, I observed markedly negative effects of MXC exposure on testosterone concentrations in pre-pubescent male mice. From our biochemical determinations, I observed some changes that indicate renal and hepatic failure. Together, these data suggest that MXC produces adverse effects on the reproductive system, kidney and liver.

• The Korean Journal of Physiology and Pharmacology
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• 제9권1호
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• pp.9-15
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• 2005

We attempted to analyze the mechanism of polychlorinated biphenyl (PCB)-induced neurotoxicity and identify the target molecules in the neuronal cells for PCBs.Since the developing neuron is particularly sensitive to PCB-induced neurotoxicity, we isolated cerebellar granule cells derived from 7-day old Sprague Dawley (SD) rats and grew cells in culture for additional 7 days to mimic PND-14 conditions. Only non-coplanar PCBs at a high dose showed a significant increase of total protein kinase C (PKC) activity at phobol 12,13-dibutyrate ([$^3M$]PDBu) binding assay, indicating that non-coplanar PCBs are more neuroactive than coplanar PCBs in neuronal cells. PKC isozymes were immunoblotted with the selected monoclonal antibodies. PKC-${\alpha}$, ${\delta}$, and ε were activated with non-coplanar PCB exposure. Receptor for activated C kinase-1 (RACK-1), anchoring protein for activated PKC, was more induced with exposure to coplanar PCBs than non-coplanar PCBs. Reverse transcription PCR (RT-PCR) analysis showed induction of neurogranin (RC-3) and growth associated protein-43 (GAP-43) mRNA with non-coplanar PCBs. The results indicate that these factors may be useful biomarkers for differentiating non-coplanar PCBs from coplanar PCBs. The present study demonstrated that non-coplanar PCBs are more neuroactive congeners than coplanar PCBs.

• 한국환경성돌연변이발암원학회지
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• 제22권2호
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• pp.125-132
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• 2002

To evaluate the modifying effect of Kwao Kreu, Pueraria mirifica (PM) well-known as a rejuvenating folk medicine from Thailand, peri- and post-natal studies were carried out in rats. PM extract was administered to pregnant Sprague Dawley (SD) rats by oral gavage from gestation 6 (GD 6) to postnatal day 21 (PND 21). The amount of administered in this study was 0.042, 0.42 and 4.2 mg/kg/day, respectively. There were no treatment related changes of dams in deaths, clinical signs, and parturition. Treatment related changes in body weight, food consumption and lactation of dams were not observed. F1 fetuses in external abnormality, physical development, reflex/sensory functions and behavioral development were not found. No adults and F1 fetuses in organ weight was found with the exception of vagina and uterus of F1 fetuses. The results showed that PM extract, up to 4.2 mg, had no adverse effects on the peri- and post-natal development of rats. Therefore, PM extract has no adverse effects on peri- and post-natal development of rats.

• 한국세라믹학회지
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• 제47권4호
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• pp.333-337
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• 2010

Domain structure and polarization switching in (001)-oriented $Pb(Mg_{1/3}Nb_{2/3})O_3-x%PbTiO_3$ (PMN-x%PT) crystals for x=20 and 35at% have been investigated in-situ by scanning force microscope (SFM) in a piezoresponse mode under a step DC electrical voltage. In the initial annealed condition, polar nano domains (PND) and domain striations oriented along {110} were observed in x=20 and x=35, respectively. For x=20, domain switching occurs by heterogeneous nucleation, where nucleation is not confined in the vicinity of domain boundaries, but rather can occur throughout the crystal volume. However, for x=35, domain switching tends to be preferentially initiated near pre-existing twin boundaries. With increasing the applying voltage, the nuclei density increased and assembled into {110} striations, indicating a stress-accommodated domain growth process. At higher voltage, nucleation occurs heterogeneously throughout the crystal volume.

• 한국세라믹학회지
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• 제51권3호
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• pp.218-223
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• 2014

The domain structures, dielectric properties, and phase transformation of (001)-oriented $Pb(Mg_{1/3}Nb_{2/3})O_3-x%PbTiO_3$ (PMN-x%PT) crystals for x=20, 30, 35, and 40 mole% have been investigated. PMN-20%PT consists of polar nano-domains (PND) which do not self-assemble into macro-domain plates. PMN-30%PT consists of PNDs which begin to self-assemble into colonies along preferred {110} planes. PMN-35PT consists of miniature polar domains on the nm scale. PMN-40%PT consists of {001} oriented lamella domains on the mm scale that have internal nano-scale heterogeneities. The dielectric properties of poled (001) PMN-x%PT single crystals have been measured for orientations both parallel and perpendicular to the [001] poling direction. The results of the temperature dependence of the dielectric constant and mesh scans for the 30%PT sample demonstrate that the initial monoclinic phase changes to single domain tetragonal phase and to cubic phase with increasing temperature.

• 성인간호학회지
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• 제17권1호
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• pp.56-67
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• 2005

Purpose: The main purpose of this study was to examine the effectiveness of a standardized telephone monitoring intervention in addressing the symptom experience and improving self-management ability in patients with heart failure. Methods: A non-equivalent control group pre-post test design was used. There were 17 patients in the experimental group, and 16 in the control group. According to the protocol, patients in the experimental group received 15 to 30 minute-telephone monitoring four times, once a week for 4 weeks. Data were analyzed by ${\chi}^2$-test, Mann-Whitney U test. Results: 1) The experimental group showed a significant increase in compliance with self-management compared to the control group. 2) There was a significant decrease in degree for 3 symptoms(DOE, PND, & continuing fatigue) in the experimental group, after telephone monitoring. However, the experimental group did not show significant decrease in the degree of the total symptom experiences. Conclusions: The results of this study provide evidence that standardized telephone monitoring is effective in relieving symptom experience and improving self-management in patients with heart failure over the course of telephone monitoring.

• 대한공간정보학회지
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• 제24권2호
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• pp.37-46
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• 2016

The difference between definition time of GPS (Global Positioning System) position data and actual display time of car positions on a map could reduce the accuracy of car positions displayed in PND (Portable Navigation Device)-type CNS (Car Navigation System). Due to the time difference, the position of the car displayed on the map is not its current position, so an improved method to fix these problems is required. It is expected that a method that uses predicted future positionsto compensate for the delay caused by processing and display of the received GPS signals could mitigate these problems. Therefore, in this study an analysis was conducted to correct late processing problems of map positions by mapmatching using a Kalman filter with only GPS position data and a RRF (Road Reduction Filter) technique in a light-weight CNS. The effects on routing services are examined by analyzing differences that are decomposed into along and across the road elements relative to the direction of advancing car. The results indicate that it is possible to improve the positional accuracy in the along-the-road direction of a light-weight CNS device that uses only GPS position data, by applying a Kalman filter and RRF.

• Environmental Analysis Health and Toxicology
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• 제22권3호
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• pp.279-285
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• 2007

The present study attempted to analyze the mechanism of PCB-induced neurotoxicity with respect to the PKC signaling. Since the developing neuron is particularly sensitive to PCB-induced neurotoxicity, we isolated cerebellar granule cells derived from 7-day old SD rats and grew cells in culture for additional 7 days to mimic PND-14 conditions. Only non-coplanar PCBs at a high dose showed a significant increase of total PKC activity at $[^3H]PDBu$ binding assay, indicating that non-coplanar PCBs are more neuroactive than coplanar PCBs in neuronal cells. PKC isoforms were immunoblotted with respective monoclonal antibodies. PKC-alpha and-epsilon were activated with non-coplanar PCB exposure. The result suggests that coplanar PCBs have a PKC pathway different from non-coplanar PCBs. Activation of PKC with exposure was dampened with treatment of high molecular weight of chitosan. Chilean (M.W. > 1,000 kDa) inhibited the total activity of PKC induced by the non-coplanar PCBs. Translocation of PKC isoforms was also inhibited by the high molecular weight of chitosan. The study demonstrated that non-coplanar PCBs are more potent neurotoxic congeners than coplanar PCBs and the alteration of PKC activities by PCB exposure can be blocked with the treatment of chitosan. The results suggest a potential use of chitosan as a means of nutritional intervention to prevent the harmful effects of pollutant-derived diseases.

• 한국재료학회지
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• 제19권6호
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• pp.300-304
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• 2009

The domain structures of annealed (001)-oriented $Pb(Mg_{1/3}Nb_{2/3})O_3-x%PbTiO_3$ (PMN-x%PT) crystals for x = 10, 20, 30, 35, and 40 at% were investigated by Polarized Optical Microscopy (POM) and Scanning Force Microscopy (SFM) in the piezoresponse mode. Both Polar Nano-Domains (PND) and long strip-like domains were clearly observed. The results also showed how the domain structure changed between phases with an increasing x in the PMN-x%PT crystals and the domain hierarchy on various length scales ranging from 40 nm to 0.1 mm. Distorted pseudo-cubic phase (x < 20%) consisted of PNDs that did not self-assemble into macro-domain plates. The rhombohedral phase (x = 30%) consisted of PNDs that began to self-assemble into colonies along preferred {110} planes. The monoclinic phase (x = 35%) consisted of miniature polar domains on the nm scale, whereas, the tetragonal phase (x = 40%) consisted of {001} oriented lamella domains on the mm scale that had internal nano-scale heterogeneities, which self-assembled into macro-domain plates oriented along {001} the mm scale.

• Toxicological Research
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• 제12권2호
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• pp.171-179
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• 1996

To investigate the involvement of $5-HT_{2A}/ 5-HT_{2C} receptors in the developmental toxicity of cocaine in rats, mianserin (2.5 mg/kg), a $5-HT_{2A}/5-HT_{2C}$ receptor antagonist, and/or cocaine HCl (45 mg/kg) were administered intraperitoneally (i.p.), during postnatal days (PND) 7-13. Behavioral assessments for the rat pups were done after 100 days of age by using the progressive ratio schedule of reinforcement (FR 1-FR 128, doubled everyday) and cocaine challenge (5, 15 or 30 mg/kg i.p.) upon established FR 32 behavior. Cocaine injected just prior to the FR 32 session suppressed the established FR 32 responding in a dose-dependent manner. The low dose of cocaine did not affect the FR 32 responding, while the high dose of cocaine suppressed it in all experimental groups. However, by the middle dose of cocaine, rats previously received water-cocaine in their early life showed a marked resistance to cocaine-induced behavioral suppression, and this resistance was not observed in rats received both mianserin and cocaine in their early life. These results suggest that $5-HT_{2A}/ 5-HT_{2C}$ receptors may have an important role for the persistently altered behavioral sensitivity to cocaine caused by exposure to cocaine during development.