• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.53-61
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• 1999

The present study was designed to investigate the effects of gonadotrophins on in vitro growth and maturation in mouse preantral follicles. Ovaries were removed from 12-day-old ICR mice. Follicles were dissociated enzymetically in Leibovitz L-15 medium containing 1 mg/$m\ell$ collagenase and 0.2 mg/$m\ell$ DNase I. The follicles were cultured on Transwell-COL membrane inserts in six well cluster dishes for 10 days. The culture medium was $\alpha$MEM medium supplemented with 5% fetal bovine serum and FSH or HMG. After 10 days of growth in vitro, follicles were allowed to mature for 18~20 hr in medium supplemented with 1.5 IU/$m\ell$ hCG. The oocytes were then denuded of their cumulus cells and assessed maturation status. Concentrations of oestradiol and progesterone were measured with a radioimmunoassay. Oocyte diameter was determined with an ocular micrometer. The survival and Metaphase II rates of oocytes were significantly higher in FSH treatment groups than in control group (P＜0.001), but there were no differences among the groups of treated FSH concentration. The survival and Metaphase II rates of oocytes in HMG treatment group (60.9 and 40.6%) were higher than in FSH treatment group (76.6 and 48.2%) and control group (49.2 and 7.1%). The survival and Metaphase II rates of oocytes on both FSH and LH treatment groups were no differences among the ratios of FSH and LH. Diameter of oocyte was no differences among the treatment groups, but smaller than compared to in vivo grown oocyte. Through the entire culture period, secretions of oestradiol and progesterone were significantly less in control group than in HMG and FSH treatment groups. These results suggest that gonadotrophins playa key role in in vitro culture of mouse preantral follicles. Especially, addition of FSH and LH should be more effective than FSH alone.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.439-449
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• 2000

This study was to investigate the expression of transgene after co-injection of spermatozoon and EGFP gene into mature oocytes in cattle. From frozen semen, spermatozoa were treated by DTT with 0.03% Tween-20, freezing and thawing or 0.02% Triton X-100 to disrupt their plasma membranes. The sperm injected oocytes were co-cultured with bovine oviduct epithelial cells in CRlaa, and expression of EGFP in embryos were observbed under epifluorescent microscope. Two pronuclei were formed in oocytes injected with sperm treated by DTT (44.6%), DTT-Tween-20 (48.4%), DTT-freezing (44.4%) and DTT-Triton X-100 (42.9%). Cleavage and blastocyst formation rates of bovine oocytes which injected with sperm treated by DTT, DTT-Tween-20, DTT-freezing, and DTT-Triton X-100 were 49.1, 58.5, 43.9, and 48.4% and 10.2, 13.0, 6.8, and 6.5%, respectively. Although the most of embryos were showing mosaicism, embryos expressing EGFP gene were observed in all treated groups. Therefore, these results indicate that membrane disrupted sperm could interact with exogenous DNA, and that this procedure may be useful to introduce foreign gene into bovine oocytes.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.165-174
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• 1999

We explore the question of whether adenosine 5'-triphosphate (ATP) acts as an excitatory neurotransmitter in guinea-pig gastric smooth muscle. In an organ bath system, isometric force of the circular smooth muscle of guinea-pig gastric antrum was measured in the presence of atropine and guanethidine. Under electrical field stimulation (EFS) at high frequencies (＞20 Hz), NO-mediated relaxation during EFS was followed by a strong contraction after the cessation of EFS (a 'rebound-contraction'). Exogenous ATP mimicked the rebound-contraction. A known $P_{2Y}-purinoceptor$ antagonist, reactive blue 2 (RB-2), blocked the rebound-contraction while selective desensitization of $P_{2Y}-purinoceptor$ with ${\alpha},{\beta}-MeATP$ did not affect it. ATP and 2-MeSATP induced smooth muscle contraction, which was effectively blocked by RB-2 and suramin, a nonselective $P_2-purinoceptor$ antagonist. Particularly, in the presence of RB-2, exogenous ATP and 2-MeSATP inhibited spontaneous phasic contractions, suggesting the existence of different populations of purinoceptors. Both the rebound-contraction and the agonist-induced contraction were not inhibited by indomethacin. The rank orders of agonists' potency were 2-MeSATP > ATP ${ge}$ UTP for contraction and ${\alpha},{\beta}-MeATP\;{\ge}\;{\beta},{\gamma}-MeATP$ for inhibition of the phasic contraction, that accord with the commonly accepted rank order of the classical $P_{2Y}-purinoceptor$ subtypes. Electrical activities of smooth muscles were only slightly influenced by ATP and 2-MeSATP, whereas ${\alpha},{\beta}-MeATP$ attenuated slow waves with membrane hyperpolarization. From the above results, it is suggested that ATP acts as an excitatory neurotransmitter, which mediates the rebound-contraction via $P_{2Y}-purinoceptor$ in guinea-pig gastric antrum.

• The Korean Journal of Pharmacology
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• v.21 no.2
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• pp.79-89
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• 1985

Mechanism of calcium transport inhibition of cardiac sarcoplasmic reticulum (SR) by oxygen free radicals was examined. Effects of oxygen free radicals generated by xanthine/xanthine oxidase (X/XO) system on isolated porcine ventricle SR were studied with respect to its calcium binding, lipid peroxidation, SH-group content and alteration of membrane protein components. The results are as follows. 1) Calcium binding of isolated SR was markedly inhibited by X/XO. 2) During the incubation of sarcoplasmic reticulum with xanthine/xanthine oxidase, there were marked inclose in lipid peroxidation and reduction of SH-group content. 3) An antioxidant, p-phenylenediamine effectively prevented the lipid peroxidation but partially prevented the calcium binding inhibition of X/XO treated SR. 4) The reduction of SH-group content of SR treated with X/XO was partially prevented by p-phenylendiamine. 5) When modifying SH-group of SR by treatment with DTNB, the inhibition of calcium binding activity was partially prevented. 6) On gel-permeation chromatography of X/XO-treated sarcoplasmic reticulum, there was an increase of small molecular weight products, probably protein degradation products. 7) Semicarbazide, which prevents the cross-linking reaction of protein components, did not affect the calcium binding inhibition of X/XO-treated SR. From these results, it is suggested that the inhibition of calcium binding of SR by oxygen free radicals results from the consequence of multiple changes of SR components, which are lipid peroxidation, SH-group oxidation and degradation of protein components.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.3
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• pp.225-231
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• 1997

As it has been reported that the depolarization-induced norepinephrine (NE) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor and various lines of evidence indicate the involvement of adenylate cyclase system in $A_1-adenosine$ post-receptor mechanism in hippocampus, it was attempted to delineate the role of adenylate cyclase system in the $A_1-receptor-mediated$ control of NE release in this study. Slices from rat hippocampus were equilibrated with $[^3H]-NE$ and the release of the labelled products was evoked by electrical stimulation.(3 Hz, $5Vcm^{-1}$, 2 ms, rectangular pulses). The influence of various agents on the evoked tritium-outflow was investigated. $N^6-Cyclopentyladenosine$ (CPA), a specific $A_1-adenosine$ receptor agonist, in concentrations Tanging from 0.1 to $10{\mu}M$ decreased the $[^3H]-NE$ release in a dose-dependent mauler without any change of basal rate of release. 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, $2{\mu}M$), a selective $A_1-receptor$ antagonist, inhibited the CPA effect. The responses to N-ethylmaleimide $(3&10{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked NE-release and the CPA effects were completely abolished by NEM pretreatment. Forskolin, a specific adenylate cyclase activator, in concentrations ranging from 0.1 to $30{\mu}M$ increased the evoked and basal rate of NE release in a dose-dependent manner and the CPA effects were inhibited by forskolin pretreatment. Rolipram $(1&10{\mu}M)$, a phosphodiesterase inhibitor, did not affect the evoked NE release but reduced the CPA effect. And 8-bromo-cAMP $(100&300{\mu}M)$, a membrane permeable cAMP analogue inhibited the CPA effect significantly. These results suggest that the $A_1-adenosine$ heteroreceptor plays an important role in NE-release via nucleotide-binding protein $G_i$ in the rat hippocampus and that the adenylate cyclase system might be participated in this process.

• The Korean Journal of Pesticide Science
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• v.13 no.2
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• pp.117-125
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• 2009

Phenylformamidine derivatives are well known as insecticides for their specific activity against the insects. It has now been established that they show insecticidal activity as agonists on the octopamine receptor which is located in the synapse membrane. The reaction of triethylorthoformate and fluoroanilines gave formimidates (1) in good yields and N',N'-Disubstituted N-fluorophenylformamidine derivatives were synthesized more easily by using microwave. This microwave reaction condition gave products in high yields and faster reaction time than conventional methods. All the compounds were screened for their biological activity agaist harmful insects of plant hoppers, moths, aphids and mites. Synthetic compounds of 2-I-a, 2-I-c, 2-I-d, 2-II-d showed good activity against mites and plant hoppers.

• Korean Journal of Environmental Biology
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• v.18 no.3
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• pp.323-330
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• 2000

Early life history and spawning for Odontobutis interrupta were observed in the laboratory during May-August 1999 with a condition of natural habitats in the field. Optimal water temperature for spawning was between 17.5 and 22.$0^{\circ}C$ and appropriate water depth and current velocity in the natural habitat ranged 0.3-0.6 m and 0.1-0.3 m/sec, respectively. Ovary maturation index peaked at about 100mm in the total length and their values gradually decreased after the size. Male fishes showed a territory and courtship behavior to adult females and the males frequently pushed upper-ventral part of females for egg releases. After females spawned, the males guarded the egg masses and supplied dissolved oxygen using pectoral fins. According to observation of egg development in the laboratory, blastodisc formed in 1hr 17 min after the fertilization, cleavaging at 36-minute interval regularly. Blastulation occurred in 7 hr 12 min after the fertilization, with gastrulation after 11 hr 11 mins and formation of york plug after 32 hr 48 min. Embryo was formed in 33 hr 45 min after fertilization and optic vesicles appeared in 47 hr 27 mins when 30-31 somites were formed. Cardiac primordium was formed in 65 hr 15mins and its beat averaged 44- 48 time/min. Pectoral fins were formed in 138 hr 40 min, air-bladder and black vesicles were observed in lower portion of young fish. Embryo hatched from she-11 membrane after about 10 days and juvenile was 5.8$\pm$0.2mm in total length 3.0$\pm$0.5mg in weight.

• Applied Microscopy
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• v.33 no.1
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• pp.1-16
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• 2003

As is well known that N-nitroso-N-methylurethane (NNNMU) causes acute lung injury (ALI) in experimental animals. And ALI caused by NNNMU is very similar to ARDS in human being in its pathology and progress. In its context, we investigated the pathogenetic mechanism of ARDS associated with oxidative stress by neutrophils in Sprague-Dawley rat model of NNNMU-induced ALI. NNNMU had increased lung weight/body weight ratio (L/B ratio), lung myeloperoxidase (MPO) activity, protein content and number of neutrophils in bronchoalveolar fluid (BALF) compared with those of control rat (p<0.001, respectively). In contrast, the amount of pulmonary surfactant in BALF was decreased by NNNMU (p<0.001). Morphologically, light microscopic examination denoted pathological findings such as formation of hyaline membrane, infiltration of neutrophils and perivascular cuffing in the lungs of NNNMU-treated rats. In addition, ultrastructural changes such as the necrosis of endothelial cells, swelling and vacuolization of lamellar bodies of alveolar type II cells, and the degeneration of pulmonary surfactant were identified after treatment of NNNMU. Very interestingly, cerium chloride electron microscopic cytochemistry showed that NNNMU had increased the production of cerrous-peroxide granules in the lung, which signified the increased production of hydrogen peroxide in the lung. Collectively, we conclude that NNNMU causes acute lung leak by the mechanism of neutrophilic oxidative stress of the lung.

• Applied Microscopy
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• v.33 no.1
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• pp.25-39
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• 2003

Cell differentiation and ultrastructural characteristics in the seminiferous epithelium of Myotis macrodactylus was investigated with the light and electron microscopes. Spermatogenesis has begun at April and finished at September. The nuclei of A spermatogonia (dark and pale type of spermatogonia) were oval, applied to the basal lamina, and surrounded by Sertoli cells. By comparison with other types of spermatogonia, the cell and nucleus of B type of spermatogonium is globular and larger than A types of spermatogonia. The nucleolus appears as a coarse and touches the nuclear membrane. The cell and nucleus of spermatocytes was globular and larger, but primary spematocyte is larger than secondary spermatocyte. Spermiogenesis was divided according to the level of fine structural difference, into Golgi, cap, acrosomal, maturation and spermiation phases; Golgi, cap, acrosomal and spermiation phases were further subdivided into steps of early and late phase respectively, and maturation phase has only one step. Hence, the spermiogenesis has been divided into a total of nine phases. In the change of karyoplasm, the chromatin granules are condensed at late Golgi phase and completed at spermiation phase. The sperm tail began to develop in early Golgi phase and completed in spermiation phase. The process of degeneration of spermatogenic cells in the seminiferous tubules was continually observed from October, before the beginning of hibernation, to hibernation phase (November, December, January, February, March). Immatured spermatogenic cells in the seminiferous tubules have been engulfed by phagocytosis of Sertoli cells during period of degeneration. It is deduced that the adaptative strategy serves as the mechanism to regulate the effective use of energy to prepare for long hibernation and regulation of breeding cycle.

• Clinics in Shoulder and Elbow
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• v.14 no.1
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• pp.140-145
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• 2011

Purpose: Installing a radial head prosthesis has developed into a reliable procedure to replace the native radial head for treating unreconstructible radial head fracture when this is associated with an unstable elbow or forearm. A variety of implants have been developed and these are now commercially available. This article reviews the literature related to the indications, the available implants and the surgical techniques of radial head replacement arthroplasty. Materials and Methods: The main indication for a metallic radial head prosthesis is a comminuted fracture that is not amenable to reconstruction, and particularly if it is associated with complex elbow injuries. Excision of the radial head should be avoided in the presence of combined injured ligaments or interosseous membrane injury. Three different implants are available in Korea, including the bipolar, press fit monopolar and loose fit monopolar radial head prostheses. A primary technical goal of radial head arthroplasty is the insertion of an implant that closely replicates the native radial head. The major pitfall when using a metallic radial head prosthesis is the insertion of a longer implant, which results in overstuffing of the radiocapitellar joint. Results and Conclusion: Satisfactory clinical results can be anticipated when a radial head prosthesis is used for the correct indications and when a systemic approach is undertaken to ensure proper sizing. For the future studies, we need data regarding the long term outcomes and comparison of the various types of prostheses.