• Title/Summary/Keyword: Genetic Level

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Efficacy of Interferon-Gamma Treatment in Bronchial Asthma (기관지천식에서 Interferon-Gamma 치료의 효과)

  • Kim, Kwan-Hyoung;Kim, Seok-Chan;Kim, Young-Kyoon;Kwon, Soon-Seog;Kim, Chi-Hong;Moon, Hwa-Sik;Song, Jung-Sup;Park, Sung-Hak;Lee, Choong-Eon;Byun, Kwang-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.4
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    • pp.822-835
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    • 1997
  • Background : There have been many in vitro evidences that interleukin-4(IL-4) might be the most important cytokine inducing IgE synthesis from B-cells, and interferon-gamma(IFN-$\gamma$) might be a main cytokine antagonizing IL-4-mediated IgE synthesis. Recently some reports demonstrated that IFN-$\gamma$ might be used as a new therapeutic modality in some allergic diseases with high serum IgE level, such as atopic dermatitis or bronchial asthma. To evaluate the in vivo effect of IFN-$\gamma$ in bronchial asthma we tried a clinical study. Methods : Fifty bronchial asthmatics(serum IgE level over 200 IU/ml) who did not respond to inhaled or systemic corticosteroid treatment, and 17 healthy nonsmoking volunteers were included in this study. The CD 23 expressions of peripheral B-cells, the IL-4 activities of peripheral T-cells, the serum soluble CD23(sCD23) levels, and the superoxide anion(${O_2}^-$) generations by peripheral PMN were compared between bronchial asthmatics and normal subjects. The IL-4 activities of peripheral T-cells were analyzed by T-cell supernatant (T-sup)-induced CD23 expression from tonsil B-cells. In bronchial asthmatics the serum IgE levels and histamine $PC_{20}$ in addition to the above parameters were also compared before and after IFN-$\gamma$ treatment. IFN-$\gamma$ was administered subcutaneously with a weekly dose of 30,000 IU per kilogram of body weight for 4 weeks. Results : The ${O_2}^-$ generations by peripheral PMNs in bronchial asthmatics were higher than normal subjects($8.23{\pm}0.94$ vs $5.00{\pm}0.68\;nmol/1{\times}10^6$ cells, P<0.05), and significantly decreased after IFN-$\gamma$ treatment compared to initial values($3.69{\pm}0.88$ vs $8.61{\pm}1.53\;nmol/1{\times}10^6$ cells, P<0.05). CD23 expression of peripheral B-cells in bronchial asthmatics was higher than normal subjects($47.47{\pm}2.96%$, vs $31.62{\pm}1.92%$, P<0.05), but showed no significant change after IFN-$\gamma$ treatment. The serum sCD23 levels in bronchial asthmatics were slightly higher than normal subjects($191.04{\pm}23.3\;U/ml$ vs $162.85{\pm}4.85\;U/ml$), and 11(64.7%) of 17 patients showed a decreasing pattern in their serum sCD23 levels after IFN-$\gamma$ treatment. However the means of serum sCD23 levels were not different before and after IFN-$\gamma$ treatment. The IL-4 activities of peripheral T-cells in bronchial asthmatics were slightly higher than normal subjects($22.48{\pm}6.81%$ vs $18.90{\pm}2.43%$), and slightly increased after IFN-$\gamma$ treatment($27.90{\pm}2.56%$). Nine(60%) of 15 patients showed a decreasing pattern in their serum IgE levels after IFN-$\gamma$ treatment. And the levels of serum IgE were significantly decreased after IFN-$\gamma$ treatment compared to initial values ($658.67{\pm}120.84\;IU/ml$ vs $1394.32{\pm}314.42\;IU/ml$, P<0.05). Ten(83.3%) of 12 patients showed an improving pattern in bronchial hyperresponsiveness after IFN-$\gamma$ treatment, and the means of histamine $PC_{20}$ were significantly increased after IFN-$\gamma$ treatment compared to initial values ($1.22{\pm}0.29mg/ml$ vs $0.69{\pm}0.17mg/ml$, P<0.05). Conclusion : Our results suggest that IFN-$\gamma$ may be useful as well as safety in the treatment of bronchial asthmatics with high serum IgE level and that in vivo effects of IFN-$\gamma$ may be different from its in vitro effects on the regulations of IgE synthesis or the respiratory burst of PMN.

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Evaluation of Resistance to Rice Sheath Blight (Rhizoctonia solani Kühn) of Rice Germplasms at Seedling Stage (유묘접종에 의한 벼 유전자원의 벼잎집무늬마름병 저항성 평가)

  • Kim, Jeong-Ju;Baek, Man-Kee;Won, Yong-Jae;Cho, Young-Chan;Kim, Bo-Kyeong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.58 no.4
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    • pp.376-382
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    • 2013
  • Rice sheath blight (ShB), caused by Rhizoctonia solani K$\ddot{u}$hn, is one of the serious fungal disease resulting in severe yield loss in rice field worldwide. There are limited sources of genetic resistance and no commercial cultivar with high level of ShB resistance is currently available in Korea. In order to seek available resources with high level of resistance to ShB, 40 rice germplasms were used to evaluate disease reactions including ShB, leaf blast and bacterial leaf blight and these germplasms also examined agronomic traits such as days to heading, culm length, panicle length, No. of panicles, No. of spikelets per panicle and so on. There is wide variation in agronomic characters and disease reactions. Rice germplasms also showed considerably different ShB reaction caused by inoculation at seedling stage. Areumbyeo, Gayabyeo, IR579-Es44 and IR64 showed more strong reaction to ShB than the others. Especially, Gayabyeo is considerably available to develop a new variety with resistance to ShB in Korea.

Studies on Antimicrobial Susceptibility and Characteristics of R-plasmids and Antigens of High-level Gentamicin Resistant Enterococcus faecalis (Gentamicin 고도내성 Enterococcus faecalis균주의 항균제감수성, R-플라스미드 및 항원의 특성연구)

  • Kang, Hyun
    • Biomedical Science Letters
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    • v.1 no.1
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    • pp.55-72
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    • 1995
  • Forty gentamicin-resistant isolates of Enterococcus faecalis were selected from various clinical materials, determined their antimicrobial susceptibility, and studied there R-plasmid characteristics and polypeptide patterns. All of the isolates were susceptible to vancomycin. The MICs($\mu$/ml) of antimicrobial agents to the isolates were as follows; the MIC of gentamicin was 128 and $\geq$2040, ampicillin 1 and 1, chlorarmphenicol 2 and 8, erythromycin 32 and 256, and vancomycin 1 and 2. E. faecalis HL-1 strain had 8 plasmid DNA elements, HL-2 and HL-3 strains had 6, HL-4 had 7, HL-5 had 4, and HL-6 had 5. The 51.7 Kb of gentamicin resistance plasmid DNA was conjugally transferred from two strains of E. faecalis HL-1 and HL-6 to S. aureus SK 982. The plasmid transfer frequency between S. aureus SK 982 and E. faecalis HL-1 or E. faecalis HL-6 was 6.3$\times10^{-4} and 3.7$\times10^{-5}$, respectively. Plasmid curing ratio after the treatment of ethidium bromide(10$\mu$/ml) to E. faecalis tarnsconjugants R-1 and R-6 were about 51% and 67%, respectively. The tetracycline gene was located in 2.15 Kb plasmid of E. faecalis HL-1, but it was not found in the E. faecalis HL-6 by Southern blot analyses. The antigenic components of E. faecalis HL-1, HL-6, R-1 and R-6 strains were analyzed by SDS-PAGE and immunoblotting. The E. faecalis strains had 7 to 16 polypeptide bands, however their major proteins were 97.8 and 26.8 Kd. At the Immunoblotting, 97.8, 95.8, 74.8, 63.5, 33.7 and 26.8 Kd polypeptides of the strains showed major antigenic activities with patient's sera infected intra-abdominally with an E. faecalis strain.

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Changes of MCPD and Chemical Components in Soy Sauce Made of Acid-hydrolyzate of Defatted Soy protein by Fermenting the Soy Sauce koji (곡자첨가에 의한 산분해간장 발효 중 MCPD 및 주요 화학성분의 변화)

  • Yoon, Bok-Man;Park, Jae-Sean;Park, Chang-Hee;Choi, Yeong-Jin;Jun, Mun-Jin
    • Korean Journal of Food Science and Technology
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    • v.30 no.2
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    • pp.419-424
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    • 1998
  • Removal of monochloropropanediol (MCPD) and improvement of quality of the soy-sauce made from acid-hydrolyzate of defatted soy protein (SAHSP) were examined by fermenting the soy-sauce with soy-sauce koji or koji plus Pediococcus soya or/and Saccharomyces rouxii. The overall fermentation process performed in this work consisted sequentially of autodigestion of soy-sauce koji $(at\;45^{\circ}C\;for\;12\;days)$, lactic acid fermentation $(at\;30^{\circ}C\;for\;14\;days\;in\;S3\;and\;S4)$, ethanol fermentation $(at\;30^{\circ}C\;for\;14\;days\;in\;S2\;and\;S4)$,and aging $(at\;25^{\circ}C\;for\;20\;days)$. At the end of the autodigestion period, the highest MCPD removal (from the initial 38.6 ppm to 1.3 ppm) was observed in the S-2. Reducing sugar contents of the S-2 and S-4 sharply decreased from the 30th day of incubation, from the initial concentration of about 5.0% to less than 0.5% at the end of the process. Total soluble nitrogen content of all the soy-sauce products slightly increased during the overall fermentating period.The level of free glutamic acid, a major amino acid that is known to determine the taste of soy-sauce was determined to be an average value of $1270{\sim}1323\;mg/100\;mL$ of soy-sauce. The results of sensory evaluation of the fermented SAHSPs show that qualities of the S-2 and S-4 samples are nearly on the same level with that of the commercially fermented soy-sauce (p<0.05). This result suggests that the fermentation process in this work, especially the process performed with S. rouxii has a good effect for removing MCPD from SAHSP and also for improving quality of the SAHSP product.

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The Effect of Stocking Density and Strain on the Performance and Physiological Adaptive Responses in Broiler Chickens (육계에서 품종 및 사육 밀도가 생산성 및 생리적 적응성 지표에 미치는 영향)

  • Jang, In-Surk;Yun, Seo-Hyun;Ko, Young-Hyun;Kim, Se-Yun;Song, Min-Hye;Kim, Jong-Sun;Sohn, Sea-Hwan;Moon, Yang-Soo
    • Korean Journal of Poultry Science
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    • v.41 no.3
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    • pp.205-215
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    • 2014
  • The aim of this study was to determine the effects of stocking density and strain on the performance and physiological adaptive responses including the plasma corticosterone content and the level of mRNA expression of pro-inflammatory cytokines and antioxidant enzymes in broiler chicks. A total of 300 birds of two strains (150 Ross strain vs. 150 Cobb strain) aged 3-d old were allotted into two stocking densities (standard stocking density,$0.046m^2/bird$ vs. high stocking density, $0.023m^2/bird$) in battery cages by $2{\times}2$ factorial designs with ten replicates until 35 d of age. There was no significant strain effect on body weight, feed intakes and feed to gain ratio and the relative organ weights. However body weight, feed intakes and relative organ weight were found to be significantly (P<0.05) affected by the effect of stocking density. Plasma corticosterone level was not affected by both stocking density and strain effects. Hepatic mRNA expression of pro-inflammatory cytokines including interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, IL-18 and interferon-gamma (IFN-${\gamma}$) was not significantly changed by the effects of strain and stocking density. However, the mRNA expression of glutathione peroxidase (GPX) was affected by strain, showing that Ross strain decreased (P<0.05) the GPX expression. With respect to the effect of stocking density, there was a significant (P<0.05) increase in superoxide dismutase (SOD) and catalase (CAT) and GPX mRNA expression in the liver from high stocking density group. Splenic pro-inflammatory cytokine expression was not also affected by stocking density and strain, except that IL-18 mRNA significantly (P<0.05) decreased in Cobb strain under high stocking density. The mRNA expression of SOD and CAT was significantly (P<0.05) affected by the effects of stocking density and strain. In conclusion, growth performance was not affected by strain but stocking density. Although mRNA expression of major pro-inflammatory cytokines was not changed by stocking density and strain, antioxidant enzyme was significantly affected by stocking density, strain or even organ in birds under summer conditions. More detailed studies still needed to be explored to elucidate the effects of environmental conditions and genetic background on physiological responses in birds.

Genotypical Variation in Nitrate Accumulation of Lettuce and Spinach (상추와 시금치의 품종별 질산태 질소 축적 차이)

  • Chung, Jong-Bae;Lee, Yong-Woo;Choi, Hee-Youl;Park, Yong;Cho, Moon-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.38 no.1
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    • pp.38-44
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    • 2005
  • In addition to the variation in nitrate accumulation of vegetables due to environmental conditions, there is also a distinct genetic variation. The variation of nitrate accumulation in some cultivars of lettuce and spinach commonly cultivated in Korea was investigated. Ten cultivars for both lettuce and spinach were grown in plastic containers filled with a 1:1 mixture of perlite and vermiculite with application of Hoagland No. 2 nutrient solution of high nitrate content (17.3 mM N) in a greenhouse condition. Plants were harvested four weeks after transplanting four-leaf stage seedlings. Plant growth was measured by fresh and dry matter of shoot, and contents of nitrate and other inorganic ions and organic solutes including sugar, amino acids and organic acids were measured. Large and significant genotypical variations in the nitrate content of the plants were found for both lettuce and spinach, and high negative correlations between nitrate content and fresh or dry weight were found in lettuce and spinach. Variation in nitrate accumulation of lettuce and spinach cultivars was not directly related to the differences in contents of organic and inorganic solutes, and this result indicates that photosynthesis and osmotic regulation are not directly related with the nitrate accumulation. Considering the correlations between nitrate content and plant growth of this study, it can be simply suggested that different cultivars of lettuce and spinach have their own inherited growth and physiological characteristics and also optimum nitrogen level required for the growth. Therefore when available nitrogen in root media is higher than the optimum level required for the inherited growth potential, some of the excess nitrate supplied can be accumulated in plants.

Genotypes of commercial sweet corn F1 hybrids

  • Kang, Minjeong;Wang, Seunghyun;Chung, Jong-Wook;So, Yoon-Sup
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.107-107
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    • 2017
  • Sweet corns are enjoyed worldwide as processed products and fresh ears. Types of sweet corn are based on the gene(s) involved. The oldest sweet corn type has a gene called "sugary (su)". Sugary-based sweet corn was typically named "sweet corn". With its relatively short shelf life and the discovery of a complementary gene, "sugary enhanced (se)", the sweet corn (su only) was rapidly replaced with another type of sweet corns, sugary enhanced sweet corn, which has recessive homozygous su/su, se/se genotype. With the incorporation of se/se genotype into existing su/su genotype, sugary enhanced sweet corn has better shelf life and increased sweetness while maintaining its creamy texture due to high level of water soluble polysaccharide, phytoglycogen. Super sweet corn as the name implies has higher level of sweetness and better shelf life than sugary enhanced sweet corn due to "shrunken2 (sh2)" gene although there's no creamy texture of su-based sweet corns. Distinction between sh2/sh2 and su/su genotypes in seeds is phenotypically possible. The Involvement of se/se genotype under su/su genotype, however, is visually impossible. The genotype sh2/sh2 is also phenotypically epistatic to su/su genotype when both genotypes are present in an individual, meaning the seed shape for double recessive sh2/sh2 su/su genotype is much the same as sh2/sh2 +/+ genotype. Hence, identifying the double and triple recessive homozygous genotypes from su, se and sh2 genes involves a testcross to single recessive genotype, chemical analysis or DNA-based marker development. For these reasons, sweetcorn breeders were hastened to put them together into one cultivar. This, however, appears to be no longer the case. Sweet corn companies began to sell their sweet corn hybrids with different combinations of abovementioned three genes under a few different trademarks or genetic codes, i.g. Sweet $Breed^{TM}$, Sweet $Gene^{TM}$, Synergistic corn, Augmented Supersweet corn. A total of 49 commercial sweet corn F1 hybrids with B73 as a check were genotyped using DNA-based markers. The genotype of field corn inbred B73 was +/+ +/+ +/+ for su, se and sh2 as expected. All twelve sugary enhanced sweet corn hybrids had the genotype of su/su se/se +/+. Of sixteen synergistic hybrids, thirteen cultivars had su/su se/se sh2/+ genotype while the genotype of two hybrids and the remaining one hybrid was su/su se/+ sh2/+, and su/su +/+ sh2/+, respectively. The synergistic hybrids all were recessive homozygous for su gene and heterozygous for sh2 gene. Among the fifteen augmented supersweet hybrids, only one hybrid was triple recessive homozygous (su/su se/se sh2/sh2). All the other hybrids had su/su se/+ sh2/sh2 for one hybrid, su/su +/+ sh2/sh2 for three hybrids, su/+ se/se sh2/sh2 for three hybrids, su/+ se/+ sh2/sh2 for four hybrids, and su/+ +/+ sh2/sh2 for three hybrids, respectively. What was believed to be a classic super sweet corn hybrids also had various genotypic combination. There were only two hybrids that turned out to be single recessive sh2 homozygous (+/+ +/+ sh2/sh2) while all the other five hybrids could be classified as one of augmented supersweet genotypes. Implication of the results for extension service and sweet corn breeding will be discussed.

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Mesozoic Granitoids and Associated Gold-Silver Mineralization in Korea (한국 중생대 화강암류와 이에 수반된 금-은광화작용)

  • 최선규;박상준;최상훈;신홍자
    • Economic and Environmental Geology
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    • v.34 no.1
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    • pp.25-38
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    • 2001
  • Contrasts in the style of the gold-silver mineralization in geologic and tectonic settings in Korea, together with radiometric age data, reflect the genetically different nature of hydrothermal activities, coinciding with the emplacement age and depth of Mesozoic magmatic activities. It represents a clear distinction between the plutonic settings of the Jurassic Daebo orogeny and the subvolcanic environments of the Cretaceous Bulgugsa igneous activities. During the Daebo igneous activities (about 200-130 Ma) coincident with orogenic time, gold mineralization took place between 197 and 127 Ma. The Jurassic deposits commonly show several characteristics: prominent association with pegmatites, low Ag/Au ratios in the ore-concentrating parts, massive vein morphology and a distinctively simple mineralogy including Fe-rich sphalerite, galena, chalcopyrite, Au-rich eIectrum. pyrrhotite and/or pyrite. During the Bulgugsa igneous activities (120-60 Ma), the precious-metal deposits are generally characterized by such features as complex vein morphology, medium to high AgiAu ratios in the ore concentrates, and abundance of ore minerals including base-metal sulfides, Ag sulfides, native silver, Ag sulfosalts and Ag tellurides. Vein morphology, mineralogical, fluid inclusion and stable isotope results indicate the diverse genetic natures of hydrothermal systems. The Jurassic Au-dominant deposits were formed at the relatively high temperature (about 300 to 450$^{\circ}$C) and deep-crustal level (>3.0 kb) from the hydrothermal fluids containing more amounts of magmatic waters (3180; 5-10 %0). It can be explained by the dominant ore-depositing mechanisms as CO2 boiling and sulfidation, suggestive of hypo/mesothermal environments. In contrast, mineralization of the Cretaceous Au-Ag type (108-71 Ma) and Agdominant type (98-71 Ma) occurred at relatively low temperature (about 200 to 350$^{\circ}$C) and shallow-crustal level «1.0 kb) from the ore-fonning fluids containing more amounts of less-evolved meteoric waters (15180; -10-5%0). These characteristics of the Cretaceous precious-metal deposits can be attributed to the complexities in the ore-precipitating mechanisms (mixing, boiling, cooling), suggestive of epilmesothermal environments. Therefore, the differences of the emplacement depth between the Daebo and the Bulgugsa igneous activities directly influence the unique temporal and spatial association of the deposit type.

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Some Factors Affecting Bone Mineral Status of Postmenopausal Women (폐경 후 여성의 골격상태에 영향을 미치는 요인분석)

  • 오세인;이행신;이미숙;김초일;권인순;박상철
    • Korean Journal of Community Nutrition
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    • v.7 no.1
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    • pp.121-129
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    • 2002
  • Osteoporosis, the typical metabolic bone disease of the elderly, is characterized by a reduction in bone mineral density (BMD) and increased fracture risk. Genetic and environmental factors are known to play a key role in bone metabolism, and diet is also considered to be one of the important factors. The purpose of the present study was to investigate the relationship among the factors affecting BMD, including stature, body weight, age, time period since onset of menopause, and biochemical markers of bone turnover in postmenopausal women. Seventy-eight postmenopausal women who visited health promotion center for health examinations volunteered to participate in this study and they were divided into two groups according to the time period since onset of menopause : women with a time period since onset of menopause of less than 5 years (Group 1) and women with a time period since onset of menopause of 5 years or more (Group 2). The demographic characteristics and dietary intake were surveyed using a questionnaire. BMDs of the lumbar spine and femoral neck of subjects were measured by dual energy X-ray absorptiometry. Serum levels of 25-hydroxy-vitamin D and parathyroid hormone (PTH), known to be indicators of bone related hormone status, were anlyzed. Serum samples were measured for calcium, phosphorus, alkaline phosphatase, and osteocalcin as bone formation indicators, and urine was analysed for deoxypyridinoline, creatinine, calcium, and sodium as bone resorption indicators. The results are as follow : The mean BMDs of the lumbar spin and femoral neck were $1.02 \pm 0.02 g/cm^2 and 0.81 \pm 0.02 g/cm^2 respectively, and the BMD level of Group 2 was significantly lower than tat of Group 1 (p<0.01, p<0.05, respectively). The mean daily intake of energy was 1838 $\pm$ 55 kcal. When nutrient intake was compared with the recommended dietary allowances (RDA) of the subjects, only calcium, vitamin A and riboflavin intake showed means lower than the RDA. The nutrient intake did not show any significant differences between Group 1 and 2 Serum and urine levels of biochemical markers of bone turnover did not show any significant differences between Group 1 and 2, and all were within the normal range. However, the PTH and deoxypyridinoline levels showed a tendency to be higher, and the osteocalcin level to be lower in Group 2 than in Group 1. Although age and years after menopause (YAM) showed negative correlations with lumbar spine bone mineral density (LBMD) (r= -0.38, p<0.001, and r= -0.26, p< 0.05, respectively), no correlation was found with femoral neck bone mineral density (NBMD). While height, body weight and body mass index (BMI) showed a positive correlation with LBMD (r= 0.32, p<0.001, r= 0.38, p<0.001, r= 0.22, p= 0.05, respectively), only body weight and BMI showed a positive correlation with NBMD (r= 0.30, p<0.01, and r= 0.27, p<0.05, respectivley). There was no significant corealtion between BMDs and the nutrient intake of subjects, except in the case of carbohydrates (r= 0.22, p<0.05). Also, serum and urine levels of bone turnover markers showed no significant correlation with nutrient intake. On the other hand, serum osteocalcin had a positive correlation with vitamin C intake (r= 0.22, p= 0.05), and urine deoxypyridinolin showed a negative correlation with niacin intake (r= -0.22, p= 0.05). Urinary na was negatively correlated with protein intake(r= -0.23, p= 0.05). The results suggested that it is difficult to prevent the decrease in bone mass among postmenopausal women eating the usual Korean diet. However, the BMDs of the lumbar spine and femoral neck were positively related to body weight ad BMI in postmenopausal women. Therefore, this study confirmed that one of the most effective ways to minimize bone loss in postmenopausal women would be to maintain an adequate body weight with balanced nutrient intake and activity in the pre-and postmenopausal periods.

Effect of Season on Testis Function and Freezing and Fertilizing Ability of Spermatozoa in Korean Native Goat I. Seasonal Changes in Semen Characteristics and Freezing and Penetrating Ability of Sperm (한국재래산양에서 계절이 정소기능, 정자의 내동성 및 수정능력에 미치는 영향 I. 정액성상과 정자의 내동성 및 난자침입능력의 계절적 변화)

  • Kim, C.K.;Chung, Y.C.;Kim, K.S.;Yoon, J.T.;Lee, J.H.;Chung, Y.H.;Choi, S.H.;Kim, H.Y.;Kim, S.;Kwon, C.J.
    • Korean Journal of Animal Reproduction
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    • v.17 no.4
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    • pp.311-323
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    • 1994
  • This study was conducted to observe seasonal and individual changes in semen characteristics and sperm freezability, and sperm penetration into zona-free hamster eggs in Korean native goats. Buck response and change in semen characteristics to electrical stimulations was evaluated for four seasons throughout 2 years and percentage of motile sperm and normal apical ridge acrosome was investigated after equilibration and thawing for 4 seasons with 5 bucks. Sperm penetration rate was evaluated for 4 bucks. 1. Probe insertion at depth of 7cm and repeated stimulation for 3 sec was more effective(P<0.05) in buck response and semen collection than those of other conditions. 2. Semen characteristics from electrojaculation was signficantly(P<0.005) higher in spring and fall for semen volume, in spring and summer for sperm concentration and in fall for sperm motility than those in other seasons, respectively. However, there were no differences in total sperm among seasons. 3. Buck response to electrical stimulation showed significant difference(P<0.05) among individuals in all 3 seasons except winter. Significant individual difference in semen volume was only in spring and summer, but there was no indivudual difference in sperm concentration and total sperm in all season. 4. Washing of semen before freezing treatment was greatly(P<0.05) beneficial to sperm motility after thawing, no matter whether ejaculates exhibit egg yolk coagulation or not. 5. Sperm motility after glycerol equilibration was significantly(P<0.05) low in summer semen and motility after thawing was greatly(P<0.05) higher in winter semen than in other seasons. Freezability of unwashed sperm was significantly difference among bucks, but a yearly freezability of washed sperm after chilling and thawing were no differences among bucks and percentage of normal apical ridge acrosome were not different among seasons and bucks. 6. There was no significant difference in sperm motility after thawing between egg yolk levels in summer, although 20% level gave more higher motility than 5% level. 7. In summer, 3.2% glycerol and 3-h equilibration gave greatest percentage(P<0.05) of sperm motility and normal apical ridge acrosome after thawing. 8. Sperm penetration rate into zona-free hamster eggs was not different between bucks and seasons. Overall, it is concluded that to obtain maximum sperm output and successive semen freezing by electrojaculation method, buck selection with good response in all season could be basically considered and that seasonal effect on sperm freezability was more greater than that of individual bucks.

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