• Korean Journal of Veterinary Service
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• v.35 no.1
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• pp.9-17
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• 2012

The objective of the present study was to isolate and identify infectious bursal disease viruses (IBDVs) from broiler and layer chickens of outbreaks of infectious bursal disease (IBD) in three districts of Bangladesh. A total of 70 bursal samples were collected from dead broiler (n=40) and layer (n=30) chickens showing specific lesions of IBD from seven commercial poultry farms of three different districts (Mymensingh, Chittagong and Tangail) of Bangladesh during the year 2007. Five representative bursal samples from each farm were used for the isolation of IBDVs using 9-day-old embryonated eggs of seronegative flock of layer birds and for identification the samples were subjected to agar gel immunodiffusion test (AGIDT), immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Out of 35 bursal samples, IBDVs were successfully isolated from 28 (80%) samples. By AGIDT, 32 (91.4%) samples were found positive for IBDV antigen. Results of AGIDT clearly indicated that IBDVs detected in 29 bursal samples of six affected farms were identical to each other but not to IBDVs present in the remaining three samples of another farm. Indirect immunoperoxidase staining of the bursal sections revealed the presence of IBDV antigen in 32 (91.4%) samples and the IBDV antigen was detected mainly in the cortex of the lymphoid follicles of the bursal tissues. In histopathology, cell depletion, atrophy and necrosis were observed in many bursal follicles with severe edema of interfollicular septa. Of the 35 bursal samples, 34 (97.1%) samples generated 254 bp product by RT-PCR. In conclusion, the results of virus isolation and identification by AGIDT, IHC and the analysis of viral genome by RT-PCR confirmed the outbreaks of acute IBD in commercial poultry of Bangladesh. Moreover, histopathological findings and results of AGIDT gave a clear indication that the isolates from six outbreaks were different from classical strain and it seems to be of very virulent strain. On the other hand, the isolates from the other outbreak were similar to the classical strain.

• The Journal of Korean Medicine
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• v.29 no.4
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• pp.205-212
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• 2008

Background and purpose: So far it was reported that acupuncture increased cerebral blood supply and stimulated the functional activity of brain nerve cells. A previous study demonstrated a correlation between LI4-11 electro-acupuncture (EA) and rCBF increase in frontal lobe. However, there remained a need to study further using various controls in acupuncture research. Transcutaneous electrical nerve stimulation (TENS) has been used as a non-invasive control in acupuncture study. This study was to evaluate the effect of LI4-LI11 TENS on regional cerebral blood flow (rCBF) in normal volunteers using single photon emission computed tomography (SPECT) and statistical parametric mapping (SPM). Methods: In the resting state, $^{99m}Tc-ECD$ brain SPECT scans were performed on 10 normal volunteers (9 males, 1 female, mean age 26.6$\pm$0.5 years; age range from 26 to 27 years). On the other day, 7 days after the resting examination, 15 minute TENS were applied at LI 4 and LI 11 on the right side of the subjects. Immediately after LI4-LI11 TENS, the second SPECT images were obtained in the same manner as the resting state. Significant increases and decreases of regional cerebral blood flow after LI4-LI11 TENS were estimated by comparing their SPECT images with those of the resting state using paired t statistics at every voxel, which were analyzed by statistical parametric mapping with a threshold of p = 0.001, uncorrected (extent threshold: k=100 voxels). Results: TENS applied at right LI4-LI11 increased rCBF in the left somatosensory association cortex (Brodmann area 5, 7). However there was no area where LI4-11 TENS decreased rCBF. Conclusion and suggestions: These results demonstrate that right LI4-LI11 TENS increased rCBF only in corresponding somatosensory association cortex, which was different from the previous results using LI4-11 EA. It is suggested that there be a different mechanism between TENS and EA.

• The Korean Journal of Nuclear Medicine
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• v.30 no.3
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• pp.299-314
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• 1996

The purpose of the present study was to validate the use of tissue radioactivity ratios instead of regional metabolic rates for the assessment of regional metabolic changes in Alzheimer's disease(AD) with [$^{18}F$]FDG PET and to examine the correlation of ratio indices with the severity of cognitive impairment in AD. Thirty-seven AD Patients(age $68{\pm}9 yrs$, $mean{\pm}s.d.$; 36 probable and 1 definite AD), 28 patients with dementia of non-Alzheimer type(age $66{\pm}7 yrs$), and 17 healthy controls(age $66{\pm}4 yrs$) underwent [$^{18}F$]FDG PET imaging. Two simplified radioactivity ratio indices were calculated from 37-66 min image: region-to-cerebellar radioactivity ratio(RCR) and a composite radioactivity ratio(a ratio of radioactivity in the most typically affected regions over the least typically affected regions: CRR). Local cerebral metabolic rate for glucose(LCMRglu) was also measured using a three-compartment, five-parameter tracer kinetic model. The ratio indices were significantly lower in AD patients than in controls(RCR in temporoparietal cortex, $0.949{\pm}0.136$ vs. $1.238{\pm}0.129$, p=0.0004; RCR in frontal cortex, $1.027{\pm}0.128$ vs. $1.361{\pm}0.151$, p<0.0001; CRR, $0.886{\pm}0.096$ vs. $1.032{\pm}0.042$. p=0.0024). On the RCR analysis, 86% of AD patients showed a pattern of bilateral temporoparietal hypometabolism with or without frontal involvement; hypometabolism was unilateral in 11% of the patients. When bilateral temporoparietal hypometabolism was considered to be suggestive of AD, the sensitivity and specificity of the RCR analysis for the differential diagnosis of AD were 86% and 73%, respectively. The RCR was correlated significantly with the macroparameter K [$K_1k_3/(k_2+k_3)$] (r=0.775, p<0.0001) and LCMRglu(r=0.633, p=0.0002) measured using the kinetic model. In patients with AD, both average RCR of cortical association areas and CRR were correlated with Mini-Mental Status Examination(r=0.565, p=0.0145; r=0.642, p=0.0031, respectively), Clinical Dementia Rating(r=-0.576, p=0.0124; r=-0.591, p=0.0077), and total score of Mattis Dementia Rating Scale (r=0.574, p=0.0648; r=0.737, p=0.0096). There were also significant correlations between memory and language impairments and corresponding regional RCRs. The results suggest that the [$^{18}F$]FDG PET ratio indices, RCR and CRR, reflect global and regional metabolic rates and correlate with the severity of cognitive impairment in AD. The simplified ratio analysis may be clinically useful for the differential diagnosis and serial monitoring of the disease.

• Investigative Magnetic Resonance Imaging
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• v.9 no.1
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• pp.43-49
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• 2005

A few studies have shown that the function of fusiform face area is selectively involved in the perception of faces including a race difference. We investigated the neural substrates of the face-selective region called fusiform face area in the ventral occipital-temporal cortex and same-race memory superiority in the fusiform face area by the event-related fMRI. In our fMRI study, subjects (Oriental-Korean) performed the implicit distinction of the race while they consciously made familiar-judgments, regardless of whether they considered a face as Oriental-Korean or European-American. For race distinction as an implicit task, the fusiform face areas (FFA) and the right parahippocampal gyrus had a greater response to the presentation of Oriental-Korean faces than for the European-American faces, but in the conscious race distinction between Oriental-Korean and European-American faces, there was no significant difference observed in the FFA. These results suggest that different activation in the fusiform regions and right parahippocampal gyrus resulting from superiority of same-race memory could have implicitly taken place by the physiological processes of face recognition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.

• Korean journal of food and cookery science
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• v.20 no.6 s.84
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• pp.607-613
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• 2004

The purpose of this study was to investigate the quality characteristics of functional cookies made with potato peels (cortex layer) containing high amounts of glycoalkaloid. Cookies were processed by mixing ratios of 10, 15 and $20\%$ potato peel relatively to flour. The spread ratio of the cookies was increased with increasing potato peel addition. Texture measurement for the cookies on substituting $10\%$ of flour for potato peel showed a decreased hardness, but the cohesiveness and springiness were increased compared to the control and other ratios. The glycoalkaloid contents of the cookies on substituting 10, 15 and $20\%$ of the flour forpotato peel were 6.27, 9.40 and 12.54mg, respectively, which according to the USAD guidelines are safe amounts for the human body, and also enough for making functional cookies. In the sensory evaluations, the cookies with $10\%$ of the flour substituted for potato peel had the highest scores in flavor, taste, appearance and texture.

• Journal of Korean Physical Therapy Science
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• v.5 no.3
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• pp.643-650
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• 1998

Facial nerve is subject to injury at any point in the course from the cerebral cortex to the motor end plate in the face, so many etiologic varieties of facial paralysis may be encountered, including trauma, viral infection and the idiopathic. Authors have studied 39 cases of facial paralysis which had experienced of treatment in our department from March, 1996 to March, 1997 at Dong San Medical Center. The results obtained are as follows : 1) The highest age incidence showed 10 cases(24.6%) in 3rd decade 2) Among the total of 39 cases, male were 21 cases(53.8%) and female were 18cases(46.2%). 3) At the involved side, left side were 19 cases(48.7%) and right side were 18 cases(46.2%). 4) The causes of facial paralysis were; idiopathic (Bell's palsy) in 19 cases(48.7%) infectious in 6 cases(15.4%) neoplastic in 6 cases(15.4%) traumatic in 5 cases(12.9%) metabolic in 2 cases(5.1%) congenital in 1 cases(2.6%) 5) In time interval between onset of symptom and treated initial date, 26 cases(66.7%) in below 10 days and 8 cases(20.5%) in 11-20 days 6) Correlation of recovery rate according to the treated duration did not differ significantly 7)Result after treatment were satisfactory

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.191-206
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• 1988

Chick embryos which have received a single injection of the organophosphate compound,malathion (0.1 mg, 0.5 mg, 1.0 mg or 2.0 mg in 0.05 ml of corn oil) via the yolk sac at certain times (2 daya, 4 days or 6 days after incubation) have been investigated. After 9 days of incubation, chick embryos were harvested to investigate the effects of malathion on the development of cerebrum morphologically and biochemically. The effects of simultaneous injection of malathion and nicotinamide were also compared. On ultrastructural examination, neurons in cerebral cortex showed to be inhibited in their differentiation by malathion; nuclear irregularity, swelling of endoplasmic reticulum, and cytoplasmic vacuoles were observed. On cytochemical study of acetylcholinesterase(AChE) by electron microscope, the positive reaction products of this enryme were localized at the membrane of nucleus and endoplasmic reticulum of neurons. Inhibition of AChE activty was severe in groups treated with relatively low doses, which was consistent with the results of spectrophotometric analysis. The activity of lactate dehydrogenase(LDH) of cerebrum in groups treated with malathion was higher than that of the control group. The nicotinamide adenine dinucleotide(NAD) content of chick embruo treated with malathioti decreased significantly, and nicotinamide coinjection raised the NAD level as compared with the control group, thus preventing malathion-induced momhological alteration. In conclusion, it is suggested that malathion changes the ultrastructure of differentiating neurons and alters some enzyme activities in chick embryo cerebrum, and the severity of which is consistently dose-or age-dependent.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.1
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• pp.198-218
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• 2002

On the basis of Imjeungjinamuian(臨證指南醫案), authors investigated the pathogenesis and treatment of ophthalmotolaryngobgic diseases from the viewpoint of Onbyeong(溫病). 1. The symptoms and diseases investigated according to department were as follows;. 1) Ophthalmology : blepharitis, blepharedema, lacrimal hypersecretion, hyperemia, ophthalmalgla, photopsia, visual disturbance, mydriasis 2) Otology : full-feeling, otorrhea, otalgla, mastoiditis, tinnitus, hearing disturbance, vertigo 3) Rhinology : rhinorrhea, nasal obstruction, sinusitis, epistaxis 4) Laryngology : sore throat, hoarseness 5) The Others : headache, cough, asthma 2. The pathogenesis and treatment of ophthalmotolaryngologic diseases were as follows. 1) When the pathogenesis of hyperemia, otorrhea, otalgia, mastoiditis, hearing disturhance. epistaxis, sore throat, headache and cough are wind-stagnanc(風鬱), wind-warm(風溫), wind-fire(風火), wind-dryness(風燥), dryness-heat(燥熱), the treatment of pungent-cool-evaporating(辛凉解表) with Dajosan(茶調散), Mori Folium(桑葉), Lonicerae Flos(金銀花), Forsythiae Fructus(連翹), Viticis Fructus(蔓荊子), Prunellae Spica(夏枯草), Arctii Fructus(牛蒡子), etc can be applied. 2) When the pathogenesis of hoarseness, cough and asthma are cold(寒), cold with endogenous heat(寒包熱, 外冷內熱), water retention(水邪), fluid retention(伏飮), impairment of YangKi by overexertion(勞傷陽氣), the treatment of pungent-warm-evaporating(辛溫解表) with Mahaenggamseoktang(麻杏甘石湯), Socheongryongtang(小靑龍湯), Jeongryeokdaejosapyetang(정력대조사폐탕), Gyejitang(桂枝湯), Armeniacae Amarum Semen(杏仁), etc can be applied. 3) When the pathogenesis of photopsia, otorrhea, otalgia, rhinorrhea, sinusitis, epistaxis, sore throat, hoarseness, headache and cough are stagnancy-induced heat(鬱熱), wind-dryness(風燥), wind-heat(風熱), summer heat(暑熱), summer wind(暑風), insidious summer heat(伏暑), autumn heat(秋暑), autumn wind(秋風), autumn dryness(秋燥), dryness-heat(燥熱), heat in Ki system(氣分熱), insidious warm(溫伏), brain discharge by fire in Ki system(氣火 腦熱), heat in stomach(胃熱), endogenous fire by deficiency of Yin(陰虛內火), deficiency of Yin in stomach(胃陰虛), the treatment of Ki-cooling(淸氣) with Bangpungtongseongsan(防風通聖散), Ikweonsan(益元散), Gyejibaekhotang(桂枝白虎湯), Geumgwemaekmundongtang(금궤맥문동탕), Gyeongokgo(瓊玉膏), Sojae Semen Praeparatum(두시), Scutellariae Radix(黃芩), Phyllostachys Folium(竹葉), Adenophorae Radix(沙參), Mori Cortex(桑白皮), Fritillariae Cirrhosae Bulbus(貝母), etc can be applied. 4) When the pathogenesis of blepharitis, hyperemia, ophthalmalgia, full-feeling, otorrhea, otalgia, tinnitus, hearing disturbance, sinusitis, hoarseness, headache and cough are fire in liver(肝火), fire in gallbladder(膽火), ministerial fire in Soyang system(少陽相火), wind-stagnancy(風鬱), stagnancy-induced fire(鬱火), brain discharge by phlegm-fire(痰火 腦熱), the treatment of mediation(和解) with Gardeniae Fructus(梔子), Moutan Cortex(牧丹皮), Saigae Tataricae Cornu(羚羊角), Artemisiae Annuae Herba(靑蒿), Cyperi Rhizoma(香附子), Poria(적복령), etc can be applied. 5) When the pathogenesis of blepharedema and cough are dampness in both spleen and lung(脾肺濕) damp-heat(濕熱), damp-phlegm(濕痰), the treatment of dampness-resolving(化濕) with Poria(백복령), Coicis Semen(薏苡仁), Tetrapanacis Medulla(通草), Armeniacae Amarum Semen(杏仁), Talcum(滑石), etc can be applied. 6) When the pathogenesis of vertigo and cough are deficiency of Yong(營虛), heat in Yong, system(營熱), the treatment of Yong-cooling(淸營) with Rehmanniae Radix(生地黃), Liriopis Tuber(麥門冬), Biotae Semen(柏子仁), Lilii Bulbus(百合), Phyllostachys Folium(竹葉), etc can be applied. 7) When the pathogenesis of epistaxis are heat in blood system of heart(心血熱), reversed flow of fire(火上逆), overexertion(努力), the treatment of blood-cooling(凉血) with Rhinoceri Cornu(犀角), Rehmanniae Radix(生地黃), Moutan Cortex(牧丹皮), Salviae Miltiorrhizae Radix(丹參), Scrophulariae Radix(玄蔘), etc can be applied. 8) When the pathogenesis of nasal obstruction is pathogen-stagnancy(邪鬱), the treatment of resuscitation(開竅) with Sosang(少商, LU11) acupuncture can be applied. When the pathogenesis of hoarseness is evil Ki(穢濁), the treatment of resuscitation(開竅) with Arctii Fructus(牛蒡子), Lasiosphaera Seu Calvatia(馬勃), Curcumae Radix(鬱金), etc can be applied. When the pathogenesis of headache is stasis of both Ki and blood(氣血瘀痺), the treatment of resuscitation(開竅) with Cnidii Rhizoma(川芎), Asari Herba Cum Radice(細辛), Scorpio(全蝎), moxibustion(灸), etc can be applied. 9) When the pathogenesis of lacrimal hypersecretion, visual disturbance, mydriasis, tinnitus, hearing disturbance, sinusitis, epistaxis, hoarseness and cough are deficiency of Yin(陰虛), deficiency of kidney(腎虛), deficiency of both liver and kidney(肝腎虛), deficiency of both heart and kidney(心腎虛), brain discharge by deficiency of Yin(陰虛 腦熱), exuberance of Yang in liver(肝陽上亢), overexertion(勞損), the treatment of Yin-replenishing(滋陰) with Yukmijihwanghwan(六味地黃丸), Hojamhwan(虎潛丸), Jeobutang(猪膚湯), Lycii Fructus(枸杞子), Polygoni Multiflori Radix(何首烏), Rehmanniae Radix(生地黃), Schizandrae Fructus(五味子), Liriopis Tuber(麥門冬), Asini Gelatinum(阿膠), etc can be applied. 10) When the pathogenesis of ophthalmalgia, mydriasis, vertigo and headache are deficiency of Yin in liver(肝陰虛), exuberance of Yang in liver(肝陽上亢), endogenous wind(內風), excess in upper and deficiency in lower part(上實下虛), the treatment of Yin-replenishing(滋陰) and endogenous wind-calming(熄風) with Rehmanniae Radix Preparat(熟地黃), Lycii Fructus(枸杞子), Polygoni Multiflori Radix(何首烏), Paeoniae Radix Alba(白芍藥), Ostreae Concha(牡蠣), Saigae Tataricae Cornu(羚羊角), Chrysanthemi Flos(菊花), etc be applied. 11) When the pathogenesis of mydriasis, sinusitis, hoarseness, headache, cough and asthma are exhaustion of vital essence(精氣無收藏), brain discharge(腦髓不固), floating Yang(陽虛浮), exsanguination(失血), deficiency of both Yin and Yang(陰陽不足), overexertion(勞損), deficiency of Yang in kidney(腎陽虛), the treatment of Yang-restoring and exhaustion-arresting(回陽固脫) with Yangyeongtang(養營湯), Cheonjinhwan(天眞丸), Bokmaektang(복맥탕), Geonjungtang(建中湯), Dogihwan(都氣丸), Singihwan(腎氣丸), Jinmutang(眞武湯), Ostreae Concha(牡蠣), Nelumbinis Semen(蓮子肉), etc can be applied. 12) When the pathogenesis of lacrimal hypersecretion, vertigo and headache are deficiency of stomach and endogenous wind(胃虛內風), endogenous wind with phlegm(內風挾痰), liver check of stomach(肝木橫擾), the treatment of concomitant-treating of both liver and stomach(肝胃同治) with Paeoniae Radix Alba(白芍藥), Uncariae Ramulus Et Uncus(釣鉤藤), Gastrodiae Rhizoma(天麻), Astragali Radix(황기), Pinelliae Rhizoma(半夏), etc can be applied. When the pathogenesis of asthma is failure of kidney to promote inspiration(腎不納氣), the treatment of kidney-tonifing and inspiration-promoting(補腎納氣) with Singihwan(腎氣丸), Psoraleae Fructus(補骨脂), Juglandis Semen(胡桃), Aquilariae Resinatum Lignum(沈香), etc can be applied. When the pathogenesis of asthma is deficiency of Ki(氣虛), the treatment of Ki-reinforcing(補氣) with Sagunjatang(四君子湯), Insamgeonjungtang(人參建中湯), etc can be applied.

• Archives of Pharmacal Research
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• v.23 no.4
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• pp.353-359
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• 2000

${\alpha}_2$-Adrenoceptor antagonists, which can enhance synaptic norepinephrine levels by blocking feedback inhibition processes, are potentially useful in the treatment of disease states such. as depression, memory impairment, impotence and sexual dysfunction. (10bS)-1,2,3,5,6,10b-Hexahydropyrrolo[2,1-a]isoquinoline oxalate (YSL-3S) was evaluated in several in vitro biological tests to establish its pharmacological profile of activities as an ${\alpha}_2$-adrenoceptor antagonist. Saturation binding assay revealed that$^{3}[H]$rauwolscine bound to the $\alpha$$_2$-adrenoceptors with a Kd value of 6.3$\pm$0.5 nM and a Bmax value of 25l$\pm$39 fmol/mg protein in rat cortical synaptic membranes. Competitive binding assay showed that YSL-3S inhibited the binding of$^3[H]$rauwolscine (1 nM) in a concentration-dependent manner with a Ki value of 98.2$\pm$12.1 nM while it did not inhibit the binding of [$^3$H]cytisine (1.25 nM) to neuronal nicotinic cholinergic receptors. The Ki values of yohimbine, clonidine and norepinephrine for $^3[H]$rauwolscine binding were 15.8$\pm$1.0, 40.1$\pm$5.9 and 40.0$\pm$11.5 nM, respectively. In addition, the binding affinity of YSL-3S for ${\alpha}_2$-adrenoceptors was higher than that of its antipode and the racemic mixture. The functional activity of YSL-3S at the presynaptic ${\alpha}_2$-adrenoceptors was assessed using the prostatic portion of the rat vas deferens. Clonidine inhibited field-stimulated contractions of the vas deference in a dose-dependent manner. The presence of YSL-3S or yohimbine caused a parallel, rightward the dose-response curve of clonidine in a dose-dependent manner, indicating an antagonistic action at the presynaptic ${\alpha}_2$-adrenoceptors. The $pA_2$values of yohimbine and YSL-3S were 7.66$\pm$0.13 and 6.64$\pm$0.18, respectively. The results indicate that YSL-3S acts as a competitive antagonist at presynaptic ${\alpha}_2$ -adrenoceptors with a potency approximately ten times lower than yohimbine, but is devoid of binding affinity for neuronal nicotinic cholinergic receptors.