• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.375-380
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• 2000

The preliminary screening of several cyanobacteria, using mice bioassay, reveale the production of a hepatotoxin by the cyanobacterium Scytonema sp. strain BT 23 isolated from soil. An intraperitoneal injection of the crude toxin (LD50 56 mg/kg body wt) from this strain caused the death of the mice within 40 min, and the anmals showed slinical signs of mice within 40 min, and the animals showed clinical signs of hepatotoxicity. The toxin was purified and partially characterized. The active fraction appears to be nonpolar in nature and shows absorption peaks at 240 and 285 nm. The purified toxin had an LD50 of TEX>$100<\mu\textrm{g}/kg$ body wt and the test mice died within 40 min of toxin administration. The toxin-treated mice showed a 1.65-fold increase in liver weight at 40 min and the liver color chnged to dark red due to intrahepatic hemorrhage and pooling of blood. Furthermore, the administration of the toxin to test mice induced a 2.58, 2.63, and 2.30-fold increse in the activity of the serum enzymes alanine aminotransferase, lactate dehydrogenase, and alkaline phosphatase, respectively. Further experiments with the 14C-labeled toxin revealed a maximum accumulation of the toxin in the liver. The clinical symptoms in the mice were similar to those produced by microcystin-L.R. These results suggest that hepatotoxins may also be produced in non bloom-forming planktonic cyanobacteria.

• Transactions on Electrical and Electronic Materials
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• v.5 no.4
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• pp.133-137
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• 2004

The development of digital x-ray detector has been extensively progressed for the application of various medical modalities. In this study, we introduce a new hybrid-type x-ray detector to improve problems of a conventional direct or indirect digital x-ray image technology, which composed of multi-layer structure using a CaWO$_4$ phosphor and amorphous selenium (a-Se) photoconductor. The leakage current of our detector was found to be ∼180 pA/cm$^2$ at 10 V/m, which was significantly reduced than that of a single a-Se detector. The x-ray sensitivity was measured as the value of 4230 pC/cm$^2$/mR at 10 V/m. We found that the parylene thin film between a CaWO$_4$ phosphor and an a-Se layer acts as an insulator to prevent charge injection from indium thin oxide (ITO) electrode into an a-Se layer under applied bias.

• Biomedical Science Letters
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• v.15 no.3
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• pp.233-239
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• 2009

The aim of this study was to evaluate the photodynamic effect of various photosensitizing agents against methicillin-resistant Staphylococcus aureus (MRSA). MRSA was exposed to light from a 632 urn diode laser (15 J/$cm^2$) in the presence of various photosensitizer, such as photofrin, photogem, radachlorine and ALA. In vivo study was performed using ICR mice. Twenty eight mice had a standard wound ($100\;mm^2$) created on the dorsum, and MRSA was inoculated into the wound region. The four groups were classified as follows: (1) the untreated control group (bacteria alone), (2) the bacteria plus light group (15 J/$cm^2$), (3) the bacteria plus photofrin group (kept in the dark), and (4) the photodynamic therapy (PDT) group (bacteria, photofrin, and light). After photofrin (dose 1 mg/kg) injection, the experimental group was irradiated with 632 urn diode laser (15 J/$cm^2$) for 30 minutes after In vitro results of PDT showed the complete killing of MRSA at the photofrin, radachlorine, and photogem However, ALA-PDT was ineffective on MRSA viability. In vivo results showed that photofrin has therapeutic effect on the wound infection. These results demonstrate that selective lethal photosensitization of MRSA can be achieved using phofrin, photogem and radachlorin. Thus, PDT can inactivate MRSA survival.

• Journal of the Korean institute of surface engineering
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• v.29 no.6
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• pp.735-738
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• 1996

Amorphous nickelphthalocyanine(NiPc) thin films were prepared by vacuum evaporation and their electrochromic behavior and voltammograms were examined in the five kinds of aqueous electrolytes. Amorphous NiPc films were prepared on indium-tin-oxide(ITO) glass substrates cooled to-$120^{\circ}C$ by using liquid nitrogen under a vacuum of $2.4 \times 10^{-4}$. The voltammetric and electrochromic measurements were made using a potential galvanostat. In order to confirm the color change, optical vis-transmission spectra of the NiPc films were measured by a spectrophotometer with various electrode potential applied. The NiPc amorphous thin films exhibited most clearly electrochromism in $KNO_3$ aqueous electrolyte. The specimen films underwent 3 color transitions (from blue to yellow-green, then to red violet, then to dark blue), corresponding to the three peaks on the voltammograms in $KNO_3$ aqueous electrolyte. Blue is color of the as-prepared film. When the potential was swept, charge compensation was attained upon oxidation by injection of anions from the electrolyte and upon reduction by expulsion of anions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.432-432
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• 2007

We studied optical simulation method for ultra slim backlight system. We designed 0.7mm thickness light guide plate and combined 48 white color LEDs for 12 inch wide size TFT-LCD. We designed flat shape PMMA light guide plate with both side patterned. It have vertical prism shape on upper side and ellipse dot pattern on the other side. We targeted 4500 nit brightness and uniform emission characteristic without hot spot or dark area. At first, we designed uniform emission area with more high brightness in center area and then, debugged light entering hot spot zone and direction of outgoing light flux. Although it was designing step, we obtained good result with reverse prism optical sheet and it had good repeatability because it was based on the stamper method in injection process without laser engraving or micro groove engraving method.

• Biomolecules & Therapeutics
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• v.4 no.2
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• pp.127-137
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• 1996

This study was performed to investigate the toxicity of DA-125 in beagle dogs, an anthracycline antitumor antibiotic. The dogs were administered DA-125 i.v. at 0.0023, 0.0375, 0.15 and 0.6 mg/kg/day, 6 days/week for 26 weeks. At 0.6 mg/kg, all male and female dogs were either sacrificed moribundly or dead during the 26-week treatment. The dogs revealed inactivity, salivation, dark bloody discharge, swelling of the subcutaneous injection site, abscess, and ulceration in the abdominal wall and legs. At 0.15 mg/kg, anorexia, salivation, and swelling of the injection site were observed. The food consumption was decreased with a statistical significance at 6 and 12 weeks treatment in males of 7.6 mg/kg. At 0.0375, 0.15 and 0.6 mg/kg, body weights were decreased significantly in a dose-related fashion after 17 weeks treatment. Total white blood cell counts for male dogs at 0.6 mg/kg were lower than those of control dogs after 13 weeks treatment, which appeared mainly due to decreased neutrophils. At 0.15 mg/kg, testicular atrophy was found in all males by gross pathology and the testicular weights were significantly decreased when compared to those of control males. Microscopically, the testis showed moderate atrophy of the seminiferous tubules and marked decrease in number of spermatozoa in the epididymal tubules. At 0.6 mg/kg, petechia or echymotic hemorrhage was observed in gastrointestinal tract, heart, lungs, and other organs at the necropsy, Marked atrophy of thymus were observed in both males and females. In addition, severe testicular atrophy was noted in all males. Microscopically, gastrointestinal tract showed hemorrhage, epithelial denudation, hypermucus secretion, and atrophy of intestinal villi. Seminiferous tubules of the atrophic testis were lined with Sertoli cells only and devoid of germ cells. Severe oligospermia or aspermia was present in the epididymal tubules. Bone marrow showed marked depletion of hemopoietic cells. In addition, marked atrophy was found in the lymphoid tissue of gastrointestinal tract, various Iymph nodes, and thymus. Injection sites showed marked inflammatory response with necrosis, necrotizing vasculitis, thrombus formation, and ulceration in the skin. According to the present results, no observed effect level appeared to be 0.0375 mg/kg. At 0.15 mg/kg, testis was a target organ, while at 0.6 mg/kg hemopoietic tissue, gastrointestinal tract, and testis were considered to be target organs. At 0.6 mg/kg the test compound seems to inflict a damage on the blood vessels causing hemorrhage in the various organs and tissues.

• Korean Journal of Veterinary Research
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• v.37 no.2
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• pp.425-438
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• 1997

To assess the testicular toxicity induced by DA-125, a new anthracycline anticancer agent, the test substance was intraveneously administered to male beagle dogs at dose levels of 0, 0.0023, 0.0375, 0.15, and 0.6 mg/kg/day, 6 days a week for 26 weeks. At 0.6 mg/kg/day, 1 out of 3 dogs had died on day 42 of treatment and the other dogs were sacrificed on days 46 and 122 of treatment due to the increasingly severe clinical condition. Clinical signs considered to be related to treatment were included anorexia, vomiting, salivation, decreased activity, mucous and/or dark faeces, diarrhea, and swelling, abscess and/or ulceration of injection sites. Suppression in body weight gain, reduction in food intake, decreases in testicular weight and size, and hemorrhage of epididymis were also observed in male dogs. Microscopically, severe degenerative changes such as atrophy of seminiferous tubules, loss of germ cells, degeneration of germ cells, vacuolization of Sertoli cells, and hyperplasia of Leydig cells were observed in all dogs. Azoospermia in epididymal tubules, atrophy of epithelia in the cauda epididymis, and prostate atrophy were also found. At 0.15 mg/kg/day, anorexia, vomiting, salivation, diarrhea, and swelling of injection sites were observed. In addition, suppression in body weight gain and decreases in testicular weight and size were found in male dogs. Atrophy of seminiferous tubules, decrease of germ cells, degeneration, exfoliation and retention of germ cells, vacuolization of Sertoli cells, and hyperplasia of Leydig cells were observed by histopathological examination. Azoospermia in epididymal tubules and prostate atrophy were also found. At 0.0375 mg/kg/day, there were no clinical signs considered to be indicative of a reaction to treatment, but testicular size was significantly reduced. Microscopically, decreases in the number of spermatogonia and epidydimal speramtozoa were found. There were no evidences of general or testicular toxicity at 0.0023 mg/kg/day. These results indicate that DA-125 produces significant and persistent damage to the spermatogenic compartments of the testes in male beagle dogs.

• Fisheries and Aquatic Sciences
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• v.20 no.8
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• pp.17.1-17.8
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• 2017

Somatostatin (SS) and growth hormone-releasing hormone (GHRH) are primary factors regulating growth hormone (GH) secretion in the pituitary. To date, it remains unknown how this rhythm is controlled endogenously, although there must be coordination of circadian manners. Melatonin was the main regulator in biological rhythms, and its secretion has fluctuation by photic information. But relationship between melatonin and growth-related genes (ghrh and ss) is unclear. We investigated circadian rhythms of melatonin secretion, ghrh and ss expressions, and correlation between melatonin with growth-related genes in tiger puffer Takifugu rubripes. The melatonin secretion showed nocturnal rhythms under light and dark (LD) conditions. In constant light (LL) condition, melatonin secretion has similar patterns with LD conditions. ss1 mRNA was high during scotophase under LD conditions. But ss1 rhythms disappeared in LL conditions. Ghrh appeared opposite expression compared with melatonin levels or ss1 expression under LD and LL. In the results of the melatonin injection, ghrh and ss1 showed no significant expression compared with control groups. These results suggested that melatonin and growth-related genes have daily or circadian rhythms in the tiger puffer. Further, we need to know mechanisms of each ss and ghrh gene regulation.

• Journal of Oriental Physiology
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• v.14 no.2 s.20
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• pp.215-224
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• 1999

After Triton WR-1339 (TX; 600mg/kg) intraperitoneal injection, hepatic tissues of ICR mice were intragastric injected with Hyulboochucketang extract(HCE; 3.3ml/kg/day) were observed to investigate the suppressive effect of lipid accumulation that evoke by the antihyperlipidemic effect of HCE. These hepatic tissues were fixed in fromol-calcium solution and were cryocut. These tissues stained by H&E for general morphology, sudan black B for lipid and perchloric acid-naphthoquinone(PAN) method for cholesterol. After TX treatment, the increase of hepatocyte having meshlike cytoplasm(HHMC) were shown in all hepatic lobules and the hepatic plates were disappeared in the aggregative region of HHMC. The number of blue black colored lipid drop and dark green colored asterisk shaped cholesterol particle in hepatic cytoplasm were increased and the size of lipid drop and cholesterol particle were enlarged. But, in HCE-treated mice, the HHCM were disappeared and hapatic plate were rearranged. The number of lipid drop and cholesterol particle were decreased than TX-treated mice and the size of lipid drop and cholesterol particle were diminished. As results indicated that the HCE work on the suppression of lipid accumulation in hepatic tissue of hyperlipidemic mice caused by disturbance of lipid metabolism.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.677-687
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• 1996

This study was conducted to evaluate the tissue responses histologically to three root canal cements : Sealapex, AH-26, and zinc oxide-eugenol cement. Twelve white female Sprague-Dawley rats, weighing between 350 and 400 gm, were anesthetized with an intraperitoneal injection of Ketamine hydrochloride(0.4 ml). After shaving the sites selected(left and right scapular areas, left and right pelvic areas), the animal's backs were scrubed with soap and water, and sterilized with absolute alcohol. Each material was mixed to a thin consistency to flow out easily through a 24-guage needle, and loaded into a sterile, disposable plastic 1-ml syringe. All of the rats were injected subcutaneously with 0.1 ml of the three test sealers. Normal saline was used as a control. Animals were sacrificed after 48hr, 1, 4, and 12 weeks by overanesthetization using jars containing anesthetic ether. The tested sites were surgically removed with the surrounding tissue and fixed with 10% formalin. After 48 hours specimens were embedded in paraffin, sectioned to an average thickness of $6{\mu}m$ thick, stained with hematoxylin-eosin. The slides were examined under the light microscope. The results were obtained as follows 1. All material except the control showed various degree of inflammation on 48 hr. 2. Sealapex : In early stage, severe inflammatory cell infiltration was observed. At the 4th weeks observation, graunlomatous tissue with macrophage and foreing body giant cells containing many dark particles in their cytoplasm was observed. 3. AH-26 : Mild inflammatoy reaction was observed with AH-26 throughout the experimental period. 4. Zinc oxide-eugenol cement : Severe inflammatory cell infiltration, necrosis along the material, edema could be seen in early stage. Zinc oxide-eugenol cement maintained a moderate/severe reaction throughout the experimental period.