• The Korean Journal of Zoology
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• v.20 no.2
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• pp.101-107
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• 1977

The effects of sodium azide, cAMP, G-strophanthin and dicumarol on the ATP-ase activity and Ca uptake of the fragmented sarcoplasmic reticulum of skeletal muscle were studied and the effects were compared with respect to the enzymatic activity and Ca transport. Sodium azide (0.05 mM) and G-strophanthin (0.25mM) caused no inhibition on either ATPase activity or Ca uptake. cAMP($1\\times10^{-6}\\sim5\\times10^{-4}$) had no effect on ATPase activity while inhibited Ca uptake. Dicumarol (0.05 mM) did not inhibit ATPase activity but caused a decreased Ca uptake of heavier fraction (8,000-12,000xG) of the reticulum fragments.

• The Korean Journal of Zoology
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• v.38 no.2
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• pp.204-211
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• 1995

In an effort to develop a new therapeutic strategy for human gene therapy of solid ovarian tumor, we studied the expression of the p53 tumor suppressor Sene as well as regulatory subunits of cyclic AMP (cAMP)-dependent protein kinase in human ovarian carcinoma cells. Four cell lines (2774, Caov-3, SK-OV-3 and OVCAR-3) were selected for the analyses. The p53 transcript and protein were detected only in the 2774 cell line by Northern and Western Bnalysis. In the relatively fast growing cell line, SK-OV-3, the %rope 1 a regulstorv subunit (RIA of CAMP-dependent protein kinase was the highest among the four cell lines. The expression level of $RII\beta$ protein was low in the four cell lines examined. These results maw point to a direction to select the target gene(sl to be employed for gene therapy to control the ovarian cancer.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.106-111
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• 1996

Alginate microspheres were prepared by the emulsification process as a drug delivery system of ampicillin sodium (AMP-Na). The preparation parameters such as the concentration of calcium chloride, the stirring time and the amount of AMP-NA were investigated. The alginate microspheres containing hydroxypropylmethylcellulose (HPMC) were found to be generally spherical, discrete and had smoother surfaces when compared to without HPMC. However, there was no significant difference in the release profile of AMP-NA from alginate microspheres prepared with or without HPMC. The concentration of calcium chloride solution and the stirring time in the preparation of alginate microspheres influenced the aggregation of alginate microspheres. The amount of AMP-NA in alginate microspheres influenced the surface morphology and the practical drug content in microspheres.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.4
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• pp.602-610
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• 1993

The DDA of new active element and the DDA differential integrator are designed. The DDA can be improved matching problems of external elements in op-amp application circuits. The design of DDA is used the transconductance element, differential pair and $2{\mu}m$ design rule. In order to evaluate the performance of the CMOS DDA, we simulated the DDA voltage inverter and the DDA level shifter using the designed CMOS DDA. Furthermore, the grounded resistor and the differential integrator is designed using the CMOS DDA and we found that its characteristics are agreed to OP-AMP differential integrator's. We performed the layout of the CMOS DDA and DDA differential integrator with MOSIS $2{\mu}m$ CMOS technology.

• Development and Reproduction
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• v.22 no.1
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• pp.65-72
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• 2018

Cyclic AMP-response element binding protein zhangfei (CREBZF), a member of ATF/CREB (activating transcription factor/ cAMP response element binding protein) family, regulates numerous cellular functions and development of cells by interacting transcription factors. This study discovered the expression pattern of CREBZF in seminiferous tubule of testes during the postnatal development of mice. In testis, CREBZF mRNA expression was the highest among other organs. Immunofluorescence analyses showed that the CREBZF was specifically expressed on spermatocyte but not in spermatogonia and Sertoli cells in seminiferous epithelium of mouse testis. Semi-quantitative polymerase chain reaction (PCR) analysis showed that CREBZF transcript level was significantly elevated during postnatal development of mouse testis. Confocal imaging analysis indicated that the protein expression of CREBZF in seminiferous tubule remained low until postnatal day (PD) 14, and was dramatically increased in PD 21. Interestingly, only one type of the spermatocyte expressed CREBZF specifically among SCP3-positive spermatocytes. Taken together, these results suggest that CREBZF may be novel putative marker of the spermatocyte and regulate meiosis during postnatal development of mice.

• The Korean Journal of Zoology
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• v.30 no.2
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• pp.117-139
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• 1987

The present experiments were carried out to investigate the mode of cAMP regulation of cumulus expansion in pig. Intracellular level of cAMP in the cumulus cells was modulated by culturing porcine cumulus oocyte complexes (COC's) with forskolin, an adenylate cyclase stimulator and 3-isobutyl-1-methylxanthine (IBMX), a phosphodiesterase inhibitor. The role of calcium in the hormone induced cumulus expansion process was also studied. Forskolin in the medium stimulated cumulus expansion from the concentration of 0.01 $\mu$M and induced full expansion at l-10 $\mu$M In contrast, IBMX in the medium (20-180 $\mu$M) failed to induce the expansion. Verapamil, a calcium ion transport blocker, suppressed follicle stimulating hormone(FSH)-induced cumulus expansion in a dose dependent fashion (0.002-0. 2 mM) when the COC's were exposed to the drugs during culture period (32 hr). But verapamil did not interfere with the triggering action of FSH during early four hours of culture period. The data presented here showed that adenylate cyclase in the porcine cumulus cells may play a key role in the regulation of the intracellular cAMP level and calcium ion may be involved in the later period of cumulus expansion process.

• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.175-184
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• 2019

Mast cells are crucial as effector cells in the immediate-type allergic reaction. Lentinus edodes has been the popular edible mushroom in oriental countries and reported to have immunomodulatory, anti-tumor, anti-atherogenic, anti-viral, and anti-allergic activities. However, the roles of L. edodes in mast cell-mediated anaphylactic reaction have not been fully elucidated. In this research, we have demonstrated the effects of the methanol extract of L. edodes (MELE) on mast cell-mediated anaphylaxis-like and anaphylactic reactions. MELE suppressed systemic anaphylaxis-like reaction, plasma histamine levels, and ear swelling response in mice treated with compound 48/80. MELE also suppressed passive systemic and cutaneous anaphylaxis mediated by anti-dinitrophenyl IgE. In accordance with these findings, MELE dose-dependently decreased histamine release from RPMC evoked by compound 48/80 or the antigen-antibody reaction. To clarify the mechanism of degranulation system, intracellular cAMP levels as well as calcium influx in RPMC was evaluated. In compound 48/80-treated RPMC, MELE blocked calcium uptake into the cells. In addition, MELE elevated the intracellular cAMP content and significantly attenuated compound 48/80-induced cAMP reduction in RPMC. Taken together, we propose the clinical use of MELE in mast cell-mediated immediate-type allergic diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.731-739
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• 1997

The aim of present study is to investigate the effects of cGMP on hyperpolarization activated inward current ($I_f$), pacemaker current of the heart, in rabbit sino-atrial node cells using the whole-cell patch clamp technique. When sodium nitroprusside (SNP, $80{\mu}M$), which is known to activate guanylyl cyclase, was added, $I_f$ amplitude was increased and its activation was accelerated. However, when $I_f$ was prestimulated by isopreterenol (ISO, $1{\mu}M$), SNP reversed the effect of ISO. In the absence of ISO, SNP shifted activation curve rightward. On the contrary in the presence of ISO, SNP shifted activation curve in opposite direction. $8Br-cGMP(100\;{\mu}M)$, more potent PKG activator and worse PDE activator than cGMP, also increased basal $I_f$ but did not reverse stimulatory effect of ISO. It was probable that PKG activation seemed to be involved in SNP-induced basal $I_f$ increase. The fact that SNP inhibited ISO-stimulated $I_f$ suggested cGMP antagonize cAMP action via the activation of PDE. This possibility was supported by experiment using 3-isobutyl-1-methylxanthine (IBMX), non-specific PDE inhibitor. SNP did not affect $I_f$ when $I_f$ was stimulated by $20{\mu}M$ IBMX. Therefore, cGMP reversed the stimulatory effect of cAMP via cAMP breakdown by activating cGMP-stimulated PDE. These results suggest that PKG and PDE are involved in the modulation of $I_f$ by cGMP: PKG may facilitate $I_f$ and cGMP-stimulated PDE can counteract the stimulatory action of cAMP.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.75-84
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• 1995

Acid secretion and NO synthase activity were determined in isolated gastric glands following hypoxia/reoxygenation and acidosis to investigate the involvement of NO in acid secretion. Isolated gastric glands were exposed to hypoxia (30 min)/reoxygenation (1 h) and/or to acidosis (pH 6.0 and 4.0). Acid secretion was measured by the ratio of $[^{14}C]-aminopyrine$ accumulation between intra- and extraglands. NO synthase activity was determined by percent conversion to $[^{14}C]-citrulline\;from\;[^{14}C]L-arginine$, a precursor of NO. The results indicate that dibutyryl cAMP stimulated acid secretion dose-dependently but had no effect on NO synthase activity in basal gastric glands. Hypoxia/reoxygenation significantly suppressed acid secretion both in unstimulated and stimulated gastric glands, which was exaggerated by acidosis. Constitutive NO synthase, activity, not responded to dibutyryl cAMP, was also inhibited by hypoxia/reoxygenation and acidosis. In conclusion, pathologic state of gastric mucosa such as hypoxia/reoxygenation and acidosis suppresses both acid secretion and NO release but the role of NO in acid secretion stimulated by dibutyryl cAMP in basal gastric glands is not significant.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.347-352
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• 1999

This cDNAs were cloned with the aid of the polymerase chain reaction (PCR) by sequences based on cloned rat LH/CG and FSH receptor cDNAs. A cDNAs of LHR and FSHR were transfected into the 293 cells. Several clonal cell lines were obtained expressing different numbers of cell surface receptors. One cell lines for each LHR and FSHR were chosen, and a corresponding cell lines expressing the wild type LHR and FSHR were selected based on the number of cell surface receptor for the particular LHR and FSHR. The abilities of the LHR and FSHR to transduce the hCG and FSH signals were measured by quantitating cAMP accumulation in cells incubated with increasing concentrations of hCG and FSH. The cAMP accumulation effects for these receptors were increased by the increasing concentrations of hCG and FSH. Thus, most of the receptors expressed in cells transfected with LHR and FSHR could be detected by measuring hormone binding and cAMP response, and can utilize to study the structure function and signal transduction of the choriogonadotropins and glycoprotein hormones.