• Title/Summary/Keyword: Ovarian Function

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Ultrastructure of Oocytes During Oogenesis and Oocyte Degeneration Associated with Follicle Cells in Female Sinonovacula constricta(BIVALVIA: PHARIDAE) in Western Korea

  • Chung, Ee-Yung;Ko, Cheol-Hwan;Kang, Hee-Woong;Choi, Ki-Ho;Jun, Je-Cheon
    • Animal cells and systems
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    • v.12 no.4
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    • pp.313-319
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    • 2008
  • The ultrastructure of oocytes during oogenesis and oocyte degeneration associated with follicle cells in female Sinonovacula constricta(Lamarck, 1818) were investigated by electron microscope observations. Ovarian follicles are surrounded by a matrix of vesicular connective tissue cells(VCT cells). VCT cells contain large quantities of glycogen particles and several lipid droplets in their cytoplasm. It is suggested that VCT cells act as a source of nutrients for vitellogenesis during oogenesis. In early vitellogenic oocytes, several coated vesicles, which appear at the basal region of the oocyte, lead to the formation of membrane-bound vesicles via endocytosis. The uptake of nutritive materials in coated vesicles formed by endocytosis appears through the formation of coated pits on the oolemma during vitellogenesis. During the late stage of oogenesis, yolk precursors(yolk granules), mitochondria and lipid droplets are present in the cytoplasm of late vitellogenic oocytes. In particular, proteinaceous yolk granules containing several different components are intermingles and form immature yolk granules. In the mature oocyte, small immature yolk granules are intermingled and form large mature yolk granules. Vitellogenesis occurs through a process of autosynthesis, involving combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum in the cytoplasm of vitellogenic oocytes. The process of heterosynthesis is where extraovarian precursors are incorporated into oocytes by endocytosis at the basal region of early vitellogenic oocytes before the formation of the vitelline coat. Follicle cells appear to play an important role in vitellogenesis and oocyte degeneration. The functions of attached follicle cells to the oocyte during oocyte degeneration are phagocytosis and digestion of phagosomes originating from oocyte degeneration. After digestion of phagosomes, it is assumed that the function of follicle cells can permit a transfer of yolk precursors necessary for vitellogenesis and allows for the accumulation of glycogen and lipid during oocyte degeneration, which can be employed by vitellogenic oocytes. Follicle cells of S. constricta may possess a lysosomal system for induction of oocyte breakdown and might resorb phagosomes in the cytoplasm for nutrient accumulation during oocyte degeneration.

Impaired Spindle Checkpoint Response of Brca1-deficient Mouse Embryonic Fibroblasts (MEFs) to Nocodazole Treatment (Brca1 결손 세포주에서 nocodazole 처리에 의한 spindle checkpoint 활성화 연구)

  • Kim Myoung-Ae;Kim Hyunju;Yun Jeanho
    • Journal of Life Science
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    • v.16 no.1
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    • pp.12-16
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    • 2006
  • Genetic alternation of Brca1 predispose of breast and ovarian cancer. Brca1 plays critical role in cell cycle regulation following DNA damage. Previous studies revealed that Brca1 plays an important role in S phase and G2/M checkpoint regulation. However, whether Brca1 involves in spindle checkpoint is unclear. In this study, the role of Brca1 in cell cycle response following nocodazole, which is a reagent that depolymerizes microtubules and activates the spindle checkpoint, has been examined using wild type $p53^{-/-}\;and\;p53^{-/-}Brca1^{-/-}$ mouse embryonic fibroblasts (MEFs). While wild type and Brca1-proficient MEFs showed an acute mitotic arrest, Brca1-deficient MEFs failed to arrest at mitotic phase in response to nocodazole treatment. In double-thymidine block and nocodazole treatment experiment, a portion of $p53^{-/-}\;Brca1^{-/-}$ MEFs were clearly by-passed nocodazole induced mitotic arrest. Consistent with this, in morphologic analysis, $p53^{-/-}\;Brca1^{-/-}$ MEFs showed growing cell morphology after nocodazole treatment. Taken together, these results suggest that Brca1 protein is an important component for normal induction of spindlecheckpoint and impairment of Brca1 function could induce dysregulation of mitotic cell cycle that ultimately results in genomic instability.

Effect of Gastrodia elata Blume Extract (TVB-1000) on the Menopausal Disorder Model in Ovariectomized Rats (난소를 적출한 갱년기 장애 모델에 대한 천마추출물(TVB-1000)의 영향)

  • Hae-Ryeong Lim;Eun-Su Ji;Hak-Kyu Byun;So-Min Lee;Hyeon-Yeol Ryu;Deug-Chan Lee
    • Journal of Life Science
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    • v.33 no.3
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    • pp.252-259
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    • 2023
  • A decrease in ovarian function and sex hormone production with aging results in hormone deficiency, which causes menopause in women. Natural products have been investigated to develop estrogen-like substances to improve menopausal status in women. This study was performed to evaluate the efficacy of Gastrodia elata Blume extract (TVB-1000) in ovariectomized rats. After a recovery period of 7 days, the TVB-1000 treatment group was orally administered at 16, 40, and 100 mg/kg for 12 weeks. In the OVX-positive control group, 17β-estradiol was injected subcutaneously into the dorsal region of rats at a dose of 10 ㎍/kg. Results show that TG and LDL-C, which are cardiovascular disease markers, were significantly decreased in all concentrations of TVB-1000 administration in the treatment group, and the LDL-C/HDL-C ratio significantly decreased in the medium and high TVB-1000 concentrations of the treatment group. In addition, in the high concentration TVB-1000 treatment group, the weight of abdominal fat decreased with statistical significance. The low-dose and medium-dose administration groups showed statistical significance and the expression level of their ER-α increased, but ER-β did not show a significant change. The above experiment shows that owing to the estrogen-like effect of TVB-1000, it can be useful as a functional food material to prevent cardiovascular disease, which is one of the menopausal symptoms.

Biological Functions of N- and O-linked Oligosaccharides of Equine Chorionic Gonadotropin and Lutropin/Chorionicgonadotropin Receptor

  • Min, K. S.
    • Proceedings of the KSAR Conference
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    • 2000.10a
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    • pp.10-12
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    • 2000
  • Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$-subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$ -subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was. efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to consist of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t63I or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632-653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agonist-occupied receptors ~2- and ~17-fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

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Biological Functions of N- and O-linked Oligosaccharides of Equine Chorionic Gonadotropin and Lutropin/Chorionic Gonadotropin Receptor

  • Min, K.S.
    • Korean Journal of Animal Reproduction
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    • v.24 no.4
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    • pp.357-364
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    • 2000
  • Members of the glycoprotein family, which includes CG, LH, FSH and TSH, comprise two noncovalently linked $\alpha$- and $\beta$-subunits. Equine chorionic gonadotropin (eCG), known as PMSG, has a number of interesting and unique characteristics since it appears to be a single molecule that possesses both LH- and FSH-like activities in other species than the horse. This dual activity of eCG in heterologous species is of fundamental interest to the study of the structure-function relationships of gonadotropins and their receptors. CG and LH $\beta$ genes are different in primates. In horse, however, a single gene encodes both eCG and eLH $\beta$ -subunits. The subunit mRNA levels seem to be independently regulated and their imbalance may account for differences in the quantities of $\alpha$ - and $\beta$-subunits in the placenta and pituitary. The dual activities of eCG could be separated by removal of the N-linked oligosaccharide on the $\alpha$-subunit Asn 56 or CTP-associated O-linked oligosaccharides. The tethered-eCG was efficiently secreted and showed similar LH-like activity to the dimeric eCG. Interestingly, the FSH-like activity of the tethered-eCG was increased markedly in comparison with the native and wild type eCG. These results also suggest that this molecular can implay particular models of FSH-like activity not LH-like activity in the eCG/indicate that the constructs of tethered molecule will be useful in the study of mutants that affect subunit association and/or secretion. A single-chain analog can also be constructed to include additional hormone-specific bioactive generating potentially efficacious compounds that have only FSH-like activity. The LH/CG receptor (LH/CGR), a membrane glycoprotein that is present on testicular Leydig cells and ovarian theca, granulosa, luteal, and interstitial cells, plays a pivotal role in the regulation of gonadal development and function in males as well as in nonpregnant and pregnant females. The LH/CGR is a member of the family of G protein-coupled receptors and its structure is predicted to of a large extracellular domain connected to a bundle of seven membrane-spanning a-helices. The LH/CGR phosphorylation can be induced with a phorbol ester, but not with a calcium ionophore. The truncated form of LHR also was down-regulated normally in response to hCG stimulation. In contrast, the cell lines expressing LHR-t631 or LHR-628, the two phosphorylation-negative receptor mutant, showed a delay in the early phase of hCG-induced desensitization, a complete loss of PMA-induced desensitization, and an increase in the rate of hCG-induced receptor down-regulation. These results clearly show that residues 632~653 in the C-terminal tail of the LHR are involved in PMA-induced desensitization, hCG-induced desensitization, and hCG-induced down-regulation. Recently, constitutively activating mutations of the receptor have been identified that are associated with familial male-precocious puberty. Cells expressing LHR-D556Y bind hCG with normal affinity, exhibit a 25-fold increase in basal cAMP and respond to hCG with a normal increase in cAMP accumulation. This mutation enhances the internalization of the free and agoinst-occupied receptors ~2- and ~17- fold, respectively. We conclude that the state of activation of the LHR can modulate its basal and/or agonist-stimulated internalization. Since the internalization of hCG is involved in the termination of hCG actions, we suggest that the lack of responsiveness detected in cells expressing LHR-L435R is due to the fast rate of internalization of the bound hCG. This statement is supported by the finding that hCG responsiveness is restored when the cells are lysed and signal transduction is measured in a subcellular fraction (membranes) that cannot internalize the bound hormone.

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Endocrine dysfunction after bone marrow transplantation during childhood and adolescence (소아 및 청소년기에서 골수이식 후에 발생할 수 있는 내분비 기능 부전)

  • Jin, Hye Young;Choi, Jin-Ho;Im, Ho-Joon;Seo, Jong-Jin;Moon, Hyung-Nam;Yoo, Han-Wook
    • Clinical and Experimental Pediatrics
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    • v.53 no.3
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    • pp.420-427
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    • 2010
  • Purpose : Several complications can occur in patients who received bone marrow transplantation (BMT) during childhood and adolescence. This study aims to investigate endocrine dysfunctions after BMT so that better care can be provided to care for long-term survivors of BMT. Methods : One hundred patients (61 males, 39 females) were included in this study. Clinical parameters such as initial diagnosis, age at BMT, conditioning regimen, presence of graft-versus-host disease (GVHD), growth pattern, thyroid function, and pubertal status were retrospectively reviewed to evaluate risk factors associated with endocrine dysfunction. Results : Height standard deviation score (SDS) at BMT, after 1 year of BMT, and at the last visit were $0.08{\pm}1.04$, $-0.09{\pm}1.02$, and $-0.27{\pm}1.18$, respectively (P =0.001). Height SDS significantly decreased in patients who received total body irradiation (TBI) (P =0.017). One of the patients who received TBI demonstrated growth hormone deficiency. Thirty (31.9%) of 94 patients had compensated hypothyroidism. Incidence of compensated hypothyroidism was higher among those who had GVHD (odds ratio 2.82, P =0.025). Of the 32 patients (17 males, 15 females) who were over 14 years in male and 13 years in female at the last visit, 16 (3 males, 13 females) had increased luteinizing hormone (LH) or follicle-stimulating hormone (FSH). Abnormal elevation of LH or FSH was more common in females (odds ratio 30.3, P =0.001). Conclusion : The most common endocrine dysfunction was ovarian insufficiency. Regular check-up for endocrine function needs to be required due to high incidence of endocrine dysfunction in patients with BMT.

Investigational Studies on Reproductive Failures of Slaughtered Cows (도살빈우의 번식장애사례 조사연구)

  • 이용빈;임경순
    • Korean Journal of Animal Reproduction
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    • v.6 no.1
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    • pp.19-30
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    • 1982
  • 1. The cows slaughtered at age of 3, 4, 6, 7, 8, and 9 years old were 1.5, 1.5, 15.0, 62.5 and 4.4% respectively. 2. The cows slaughtered at 351-450kg and more than 500kg were 60 and 28% respectively. 3. Best, very good, good and bad cows in nutritional condition were 1.6, 25.8, 62.9, and 9.7% respectively. Among the six cows which were bad nutrition, the two were with severe endometritis, the three were normal in genital function and one was on 70 days of pregnancy. 4. Holstein cows(55.2%) showed higher reproductive failure than the Korean cows(33.3%). 5. The slaughted ratio of the Korean cattle and Holstein cows was 36 and 64% respectively. 6. Pregnant cows were about 16% among the slaughtered one. 7. Reproductive failures were composed of 46% in uterus, 32% in ovaries, 8% in udder, 6% in oviduct, 4% in cervix of uterine, 2% in vagina and 2% inmummified fetus. 8. Forty six percentages of uterine diseases were as follows; horn, 13%, body of uterus, 32% and ovary diseases were 32%, that is, 12% of ovary atrophy, 8% of ovarycyst and 6% of lutealcyst. 9. The cows of reproductive failures were commonly infected with 1.6 kinds of diseases. 10. According to classification, six type of ovaries were as follows; normal, 58%, ovary-cyst, 11%, luteum cyst, 4%, coexistence of follicles and corpus luteum, 16%, weak function of ovaries, 10% and ovarian atrophy, 1%. 11. Major axis, minor axis and thickness of right ovary were larger than those of left one both in Korean cattle and Holstein cows. Holstein cow had generally larger size of ovary than these of the Korean cattle.. 12. The left and right oviducts showed no difference in length, but Holstein had longer oviduct than Korean cow. 13. There was no difference in the length of uterine horn between right and left in the Korean cows, but the right was longer than the left in Holstein cows. 14. Holstein had longer horn and body of uterine than the Korean cows. 15. The weight of right ovary was heavier than that of left in both breeds, but there was no differences in weight of left ovary between two breeds and right ovary of Holstein breed was heavier than that of the Korean cow. 16. The weight of right oviduct and uterine born was heavier than that of the left, and Holstein had heavier oviducts and uterine horns than the Korean cows. 17. Holstein had heavier uterine body and cervix of uterine than the Korean cows. 18. The length of reproductive systems of Korean cow is as follows; Major and minor diameter and thickness ofovary are 3.6${\pm}$0.7, 2.3${\pm}$0.4 and 1.6${\pm}$1.4 cm in left and 3.7${\pm}$0.6, 2.5${\pm}$0.5 and 1.8${\pm}$0.5 cm in right. Oviduct is 28.4${\pm}$3.1 cm in left and 27.8${\pm}$3.3 cm in right. Uterine horn is 27.4${\pm}$4.5 cm in left and 27.7${\pm}$4.9 cm in right. Uterine body and cervix are 3.4${\pm}$1.1 and 6.5${\pm}$1.7 cm. 19. The length of female reproductive systems ofHolstein cow is as follows; Major and minor diameter and thickness of ovary are 3.9${\pm}$1.3, 2.3${\pm}$0.5, and 1.5${\pm}$0.6 cm in left and 4.0${\pm}$0.8, 2.8${\pm}$0.6 and 1.8${\pm}$0.6 cm in right. Oviduct is 29.4${\pm}$4.2 cm in left and 29.3${\pm}$4.1 cm in right. Uterine horn is 30.2${\pm}$7.4 cm in left and 32.6${\pm}$8.4 cm in right. Uterine body and cervix are 4.5${\pm}$2.5 and 7.8${\pm}$2.9 cm. 20. The weight of reproductive systems of Korean cow is as follows; Ovary is 8.4${\pm}$4.1 g in left and 9.3${\pm}$3.6g in right. Oviduct is 1.5${\pm}$0.5 g in left and 1.6${\pm}$0.5 g in right. Uterine horn is 109${\pm}$27 g left and 118${\pm}$32 g in right. Uterine body and cervix are 30.4${\pm}$14.1 and 76.7${\pm}$38.4g. 21. The weight of reproductive systems of Holstein cow is as follows; Ovary is 8.2${\pm}$3.1 g in left and 12.5${\pm}$5.6 g in right. Oviduct is 1.7${\pm}$0.6 g in left and 1.9${\pm}$0.9 g in right. Uterine horn is 199${\pm}$14.2 g in left and 221${\pm}$111.2g in right. Uterine body and cervix are 58.2${\pm}$46.5 and 126.7${\pm}$103.3 g.

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The Effect of the Serum Progesterone and Estradiol Levels of hCG Administration Day on the Pregnancy and Fertilization Rate in IVF-ET Patients (체외수정 과배란 유도에서 hCG 주사 당일의 혈청 Progesterone과 Estradiol 농도가 수정율 및 임신율에 미치는 영향에 관한 연구)

  • Lee, Eun-Sook;Lee, Sang-Hoon;Bae, Do-Hwan
    • Clinical and Experimental Reproductive Medicine
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    • v.23 no.1
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    • pp.51-59
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    • 1996
  • Controlled Ovarian hyperstimulation(COH) is generally used to obtain synchronous high quality oocytes in in vitro fertilization-embryo transfer(IVF-ET). Many investigators have studied the relationship between serum hormone levels and outcomes of IVF-ET because there is no accurate estimation method of oocyte quality. Early premature luteinization of follicles before oocyte retrieval is the most troublesome problem in COH for IVF-ET. Gonadotropin-releasing hormone agonists(GnRH-a) are used as adjuncts with gonadotropins for COH in patients undergoing in IVF. The possible benefits of GnRH-a pretreatment include improving oocyte quality, allowing a more synchronous cohort of follicles to be recruited, and preventing premature lueinization hormone surges. In COH of IVF cycles, we investigated whether an elevated progesterone(P4) level on the day of human chorionic gonadotropin(hCG) administration indicates premature luteinization and is associated with a lower fertilization rate. Many investigators have studied that the lower fertilization rates seen in patients with elevated P4 levels might result from an adverse effect of P4 on the oocytes. We hypothesizes that serum P4 levels around the day of hCG may be helpful prediction of out come in IVF-ET cycles. Success rates after COH of IVF-ET cycles are dependent upon many variable factors. Follicular factors including the number of follicles, follicular diameters and especially serum estradiol(E2) levels as an indirect measurement of follicular function and guality have been thought to influence the outcomes of IVF-ET. To assess whether serum P4 and E2 levels affect the fertilization and pregnancy rate, we reviewed the stimulation cycles of 113 patients (119 cycles) undergoing IVF-ET with short protocol with GnRH-a, from March 1993 to August 1994 retrospectively. The serum P4 and E2 levels were compared on the day of hCG in the pregnant group, 45 patients(47 cycles) and in the non-pregnant group, 68 patients (72 cycles) respectively. The serum E2 level in non-pregnant group was $1367{\pm}875.8$ pg/ml which was significantly lower than that of pregnant group, $1643{\pm}987.9$ pg/ml( p< 0.01 ). And the serum P4 level in non-pregnant group was $2.1{\pm}1.4$ ng/ml which was significantly higher than that of pregnant group, $1.0{\pm}0.7$ ng/ml( p< 0.001 ). The fertilization rate was $61.3{\pm}21.3%$ in pregnant group which was higher than that of non-pregnant group, $41.1{\pm}20.2%$ (p< 0.01). We suggest that the serum levels of P4 and E2 on the day of hCG administration are additional parameters that predict the outcomes of IVF-ET cycles.

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Effect of Suckling on Progesterone Secretion during Lactation in the Rat (포유중인 Rat 의 Progesterone 분비에 대한 포유 효과)

  • 오석두;성환후;민관식;윤창현
    • Korean Journal of Animal Reproduction
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    • v.23 no.2
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    • pp.95-103
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    • 1999
  • This experiment was conducted to investigate how the lactation regulation such as restricted-lactation and early weaning during the suckling period influences on ovarian functions and change in serum levels of progesterone in primiparous rats. All the rats were raised in the individual cage from a few days before parturition through the suckling period. The normal lactation(NL) groups were controled 8 pups. The restricted-lactation(RL) and weaned(W) groups were subdivided into 5 subgroups as RL0, RL5, RL10, RL15 and RL20 as well as W0, W5, W10, W15, and W20 according to the day of onset of suckling. The number of pups were regulated from 8 to 4 on experimental strating day in RL gropus, and also perfectly weaned on the each on-set day in W groups. The results obtained were summarized as follows: 1. During the whole suckling period of 25 days the pups in RL group grew significantly(P<005) faster than those in normal-lactation(NL) group. The pups in earlier RL group grew significantly(P<0.05) faster than those in later RL rats, and there was no found any significant difference in body weight of pups between RL20 and NL group. The gestation period and litter size were found to be 21.53$\pm$0.04 days and 13.75$\pm$0.07, respectively. 2. The estrous cycle was not expressed in the NL group through the whole suckling period. An irregular estrous cycle was found around day 20 in RL0 group, and the regular estrous cycles were exhibited continuously from day 10 in the day 0 weaned rats. 3. In the rats of NL group the serum progesterone concentration increased from 33.16$\pm$2.64ng/$m\ell$ on day 0 to 122.5$\pm$53.68 ng/$m\ell$ on day 10, and then decreased slightly to 97.30$\pm$3.21 ng/$m\ell$ on day 20, but then decreased abruptly. However, the serum level of progesterone decreased greatly(P<0.05) in 5 to 10 days following suckling restriction in the rats from which suckling began to be under restriction on day 0 or day 15. In the early weaning group the significant ( (P<0.05) decrease in progesterone concentration was found similarly in 48 hours following weaning in all the rats weaned on day 0 through day 20. It was suggested that lactation stimulation is a very pivotal on the function of ovary.

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Current Status and Future Perspective of PET (PET 이용 현황 및 전망)

  • Lee, Myung-Chul
    • The Korean Journal of Nuclear Medicine
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    • v.36 no.1
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    • pp.1-7
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    • 2002
  • Positron Emission Tomography (PET) is a nuclear medicine imaging modality that consists of systemic administration to a subject of a radiopharmaceutical labeled with a positron-emitting radionuclide. Following administration, its distribution in the organ or structure under study can be assessed as a function of time and space by (1) defecting the annihilation radiation resulting from the interaction of the positrons with matter, and (2) reconstructing the distribution of the radioactivity from a series of that used in computed tomography (CT). The nuclides most generally exhibit chemical properties that render them particularly desirable in physiological studies. The radionuclides most widely used in PET are F-18, C-11, O-15 and N-13. Regarding to the number of the current PET Centers worldwide (based on ICP data), more than 300 PET Centers were in operation in 2000. The use of PET technology grew rapidly compared to that in 1992 and 1996, particularly in the USA, which demonstrates a three-fold rise in PET installations. In 2001, 194 PET Centers were operating in the USA. In 1994, two clinical and research-oriented PET Centers at Seoul National University Hospital and Samsung Medical Center, was established as the first dedicated PET and Cyclotron machines in Korea, followed by two more PET facilities at the Korea Cancer Center Hospital, Ajou Medical Center, Yonsei University Medical Center, National Cancer Center and established their PET Center. Catholic Medical School and Pusan National University Hospital have finalized a plan to install PET machine in 2002, which results in total of nine PET Centers in Korea. Considering annual trends of PET application in four major PET centers in Korea in Asan Medical Center recent six years (from 1995 to 2000), a total of 11,564 patients have been studied every year and the number of PET studies has shown steep growth year upon year. We had 1,020 PET patients in 1995. This number increased to 1,196, 1,756, 2,379, 3,015 and 4,414 in 1996,1997,1998,1999 and 2000, respectively. The application in cardiac disorders is minimal, and among various neuropsychiatric diseases, patients with epilepsy or dementia can benefit from PET studios. Recently, we investigated brain mapping and neuroreceptor works. PET is not a key application for evaluation of the cardiac patients in Korea because of the relatively low incidence of cardiac disease and less costly procedures such as SPECT can now be performed. The changes in the application of PET studios indicate that, initially, brain PET occupied almost 60% in 1995, followed by a gradual decrease in brain application. However, overall PET use in the diagnosis and management of patients with cancer was up to 63% in 2000. The current medicare coverage policy in the USA is very important because reimbursement policy is critical for the promotion of PET. In May 1995, the Health Care Financing Administration (HCFA) began covering the PET perfusion study using Rubidium-82, evaluation of a solitary pulmonary nodule and pathologically proven non-small cell lung cancer. As of July 1999, Medicare's coverage policy expanded to include additional indications: evaluation of recurrent colorectal cancer with a rising CEA level, staging of lymphoma and detection of recurrent or metastatic melanoma. In December of 2001, National Coverage decided to expand Medicare reimbursement for broad use in 6 cancers: lung, colorecctal, lymphoma, melanoma, head and neck, and esophageal cancers; for determining revascularization in heart diseases; and for identifying epilepsy patients. In addition, PET coverage is expected to further expand to diseases affecting women, such as breast, ovarian, uterine and vaginal cancers as well as diseases like prostate cancer and Alzheimer's disease.