• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.22-27
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• 2004

In the present study, the protective effects of Artemisia capillaris (AC) on the DNA damage induced by $^{60}$ Co ${\gamma}$-rays were evaluated using alkaline single-cell gel electrophoresis (SCGE, comet assay) in the mouse peripheral lymphocytes and micronuclei (MN) formation test in the Chinese hamster ovary (CHO) cells. We also investigated the effect of AC on 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in the mouse liver and thymus exposed to ${\gamma}$-ray, The tail moment and the frequency of MN, which were markers of DNA damage in the SCGE and MN formation test, were decreased in the groups treated with AC extract before exposure to 200 cGy of ${\gamma}$-ray. We also observed its activities, lowering 8-OHdG level, an index of oxidative DNA damage, in the groups treated with AC extract before whole body ${\gamma}$-irradiation (800 cGy). It is plausible that scavenging of free radicals by AC may have played an important role in providing the protection against the radiation-induced damage to the DNA. These results indicated that AC protects the DNA damage induced by ${\gamma}$-rays and might be a useful radioprotector, especially since it is a relatively nontoxic product.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.1-6
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• 1987

This study was to observe the changes of blastogenic responses of splenic Iymphocytes to T-cell mitogens, N. fcwleri Iysate and concanaualin A, and serum antibody titer during the course of experimental PAM in mice. Naegleria fcwleri, strain 0359, was cultured in the CGVS medium axenically and inoculated intranasally with $7{\times}10^4$ trophozoites for the development of experimental PAM in mice. The amoebae were subjected to ultrasonication and centrifuged at 20,000g for 60 minutes, and filtered through $0.2{\mu\textrm{m}}$ filter membrane. The supernatant, N. fcwleri Iysate, was used as T-cell mitogen, and antigen for ELISA. The serum antibody was examined by ELISA using peroxidase conjugate. Two hundred ${\mi}l$ of $10^6$ splenocytes in RPMI 1640 containing 0% fetal calf serum were added to each well of a microtiter plate. To each well was added T-cell mitogens, $100{\mu}g/ml$ of N. fowleri Iysate or $4{\mu}g/ml$ of con. A, and the plates were incubated for 42 hours at $37^{\circ}C$ in 5% $CO_2$ incubator. Cultures were pulsed with of $methyl-(^3H)-thymidine$ 6 hour before harvesting. The mean blastogenic response of the splenocytes to N. fewleri Iysate was reduced, whereas that to con. A was also reduced up to on day 11 after infection. Both of these results were statistically significant compared with those of uninfected control group. The serum antibody titers were increased gradually up to day 15. The results indicated that there was an impairment of the blastogenic response of splenocytes to N. fowleri Iysate during the acute course of experimental PAM in mice.

• Journal of Mechanical Science and Technology
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• v.18 no.5
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• pp.770-779
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• 2004

This paper describes the micro cutting of wear resistant tungsten carbides using PCD (Poly-Crystalline Diamond) cutting tools in performance with SEM (Scanning Electron Microscope) direct observation method. Turning experiments were also carried out on this alloy (V50) using a PCD cutting tool. One of the purposes of this study is to describe clearly the cutting mechanism of tungsten carbides and the behavior of WC particles in the deformation zone in orthogonal micro cutting. Other purposes are to achieve a systematic understanding of machining characteristics and the effects of machining parameters on cutting force, machined surface and tool wear rates by the outer turning of this alloy carried out using the PCD cutting tool during these various cutting conditions. A summary of the results are as follows: (1) From the SEM direct observation in cutting the tungsten carbide, WC particles are broken and come into contact with the tool edge directly. This causes tool wear in which portions scrape the tool in a strong manner. (2) There are two chip formation types. One is where the shear angle is comparatively small and the crack of the shear plane becomes wide. The other is a type where the shear angle is above 45 degrees and the crack of the shear plane does not widen. These differences are caused by the stress condition which gives rise to the friction at the shear plane. (3) The thrust cutting forces tend to increase more rapidly than the principal forces, as the depth of cut and the cutting speed are increased preferably in the orthogonal micro cutting. (4) The tool wear on the flank face was larger than that on the rake face in the orthogonal micro cutting. (5) Three components of cutting force in the conventional turning experiments were different in balance from ordinary cutting such as the cutting of steel or cast iron. Those expressed a large value of thrust force, principal force, and feed force. (6) From the viewpoint of high efficient cutting found within this research, a proper cutting speed was 15 m/min and a proper feed rate was 0.1 mm/rev. In this case, it was found that the tool life of a PCD tool was limited to a distance of approximately 230 m. (7) When the depth of cut was 0.1 mm, there was no influence of the feed rate on the feed force. The feed force tended to decrease, as the cutting distance was long, because the tool was worn and the tool edge retreated. (8) The main tool wear of a PCD tool in this research was due to the flank wear within the maximum value of $V_{max}$ being about 260 $\mu\textrm{m}$.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.140-146
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• 2000

Recently, we reported that immunostimulation of primary rat cortical astrocyte caused stimulation of glucose deprivation induced apoptotic cell death. To enhance the understanding of the mechanism of the potentiated cell death of clucose-deprived astrocyte by immunostimulation, we investigated the effect of immunostimulation on the glucose deprivation induced cell death of rat C6 glioma cells. Co-treatment of C6 glioma cells with lipopolysaccharide (LPS, $1\;{\mu}\textrm{g}/ml$) and interferon ${\gamma}(IFN{\gamma},\;100U/ml)$ is serum free condition caused marked elevationo f nitric oxide production ($>50\;{\mu}M$). In this condition, glucose deprivation caused significant release of lactate dehdrogenase (LDH) from C6 glioma cells while control cells did not show LDH release. To investigate whether elevated level of nitric oxide is responsible for the enhanced LDH release in glucose-deprived condition, C6 glioma cells were treated with 3-morphorinosydnonimine (SIN-1) and it was observed that SIN-1 caused increase in LDH release from glucose-deprived C6 glioma cells. Treatment of C6 glioma cells with $25\;{\mu}M$ of pyrrolidinedithiocarbamate (PDTC) which inhibit Nuclear factor kB (NF-kB) activation, caused complete inhibition of nitric oxide production. Treatment of C6 glioma cells with NO synthase inhibitors, $N^{G}$-nitro-L-arginine (NNA) or L-$N{\omega}$-nitro-L-arginine methyl ester (L-NAME), caused inhibition of nitric oxide production and also glucose deprivation induced cell death of cytokine-stimulated C6 glioma cells. In addition, diaminohydroxypyrimidine (DAHP, 5 mM) which inhibits the synthesis of tetrahydrobiopterine (BH4), one of essential cofactors for iNOS activity, caused complete inhibition of NO production from immunostimulated C6 glioma cells. The results from the present study suggest that immunostimulation causes potentiation of glucose deprivation induced death of C6 glioma cells which is mediated at least in part by the increased production of nitric oxide. The vulnerability of immunostimulated C6 glioma cells to hypoglycemic insults may implicate that the elevated level of cytokines in various ischemic and neurodegenerative diseases may play a role in their pathogenesis.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.458-464
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• 1998

Search for a new $\alpha$-methylene-$\gamma$-butyrolactone-bearing 6-substituted purine as a potental antitumor agent has led to synthesize seven, hitherto unreported, $5^1$-Methyl-$5^1$-[(6-substituted-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$- methylenetetrahydrofurans (H, Cl, l, $CH_3$, $NH_2$, SH, >C=O) (6a-g). These include $5^1$-Methyl-$5^1$-[(9H-purin-9-yl)methyll-$2^1$-oxo-$3^1$ -methylenetetrahydrofurans (6a), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydr ofurans (6b), $5^1$-Methyl-$5^1$-[(6-chloro-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6c), $5^1$-Methyl-$5^1$-[(6-methyl-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6d), $5^1$-Methyl-$5^1$-[(9H-adenin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6e), $5^1$-Methyl-$5^1$-[(6-mercapto-9H-purin-9-yl) methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofurans (6f) and $5^1$-Methyl-$5^1$-[(9H-hypoxanthin-9-yl)methyll-$2^1$-oxo-$3^1$-methylenetetrahydrof urans (6g) which were made by the Reformatsky-type reaction of ethyl $\alpha$-(bromomethyl) acrylate with the corresponding (6-substituted-9H-purin-9-yl)-2-propanone intermediates (5a-g). These ketone intermediates 5a-g, 1-(9H-purin-9-yl)-2-propanone (5a), 1-(6-chloro-9H-purin-9-yl)-2-propanone (5b), 1-(6-iodo-9H-purin-9-yi)-2-propanone (5c), 1-(6-methyl-9H-purin-9-yl)-2-propanone (5d), 1-(9H-adenin-9-yl)-2-propanone (Se), 1-(6-mercapto-9H-purin-9-yl)-2-propanone (5f), and 1-(9H-hypoxanthin-9-yl)-2-propanone (5g) were directly obtained by the alkylation of the 6-substituted purine bases with the chloroacetone in the presence of $K_2$$CO_3$ (or NaH) under DMF (or DMSO). The preliminary in vitro cytotoxcity assay for the synthetic .alpha.-methylene-y-butyro-lactone compounds (6a-g) were determined against three cell lines (PM-3A, P-388, and K-562) and showed the moderate antitumor activity ($IC_50$ ranged from 1.4 to 4.3 $\mu\textrm{g}$/ml) with the compound $5^1$-methyl-$5^1$ -[(9H-hypoxanthin-9-yl)methyl]-$2^1$-oxo-$3^1$-methylenetetrahydrofuran (6g) showing the least antitumor activity.

• Journal of Embryo Transfer
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• v.17 no.2
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• pp.145-151
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• 2002

The aim of these experiments was to investigate in vitro nuclear maturation of canine oocyte collected from various stages of estrus cycles, Ovaries were obtained from 1 to 4 year-old mongrel bitch and minced for oocyte collection in phosphate buffered saline with 100 iu penicillin-G $m\ell$／sup -1／, 50 $\mu\textrm{g}$ streptomycin sulphate $m\ell$／sup -1／ and 0.1％ (w／v) polyvinyl alcohol. Cumulus-oocyte-complexes (COCs) were washed in HEPES buffered tissue culture medium (TCM)199 and in vitro matured in TCM-199 culture medium supplemented with sodium pyruvate 0.028mg/$m\ell$, L-glutamine 0.146mg／$m\ell$, penicillin G 10,000 IU／$m\ell$, streptomycin 0.031mg／$m\ell$ and 10％ (v／v) fatal calf serum. COCs were in vitro matured for 48～72 hrs at 39$^{\circ}C$ in humidified 5％ $CO_2$ in air atmosphere. In vitro matured oocytes were remove the cumulus cells using 0.2％ (v／v) hyaluronidase. After denuding, oocyte were placed in acetic acid : methanol : chlorform solusion (3:6 : 1.5 v／v) for 30 sec and acetic acid: ethanol(1:3 v／v) for 48hrs fixation. Nuclear maturation was classified to GV, GVBD, MI, MII and degenerate oocyte under microscopy after 1％ aceto-orcein stain. In vitro maturation rates at 48hrs were not significantly difference among the oocytes collected from different stage of estrus at 15.9％, 16.3％, 23.7％ and 18.2％ for anestrus, proestrus, estrus and diestrus. However, the oocytes maturation(36.6％) of collected from estrus ovaries were significantly different from oocytes derived from proesturs, diestrus and anestrus ovaries(30.8％, 17.5％ and 22.1％; p＜0.05). The overall in vitro maturation rates were significantly higher (p＜0.05) in 72hrs culture than 48hrs culture system. In summary, there was a tendency for higher in vitro maturation rates with the oocyte collected from estrus ovary than other stages of estrus. Also, for nuclear maturation, in vitro culture of oocyte for 72hrs was better than 48hrs culture.