• Interdisciplinary Bio Central
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• v.2 no.4
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• pp.16.1-16.4
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• 2010

Cryopreservation of mouse embryos and spermatozoa has become the foremost technique for preserving large numbers of different strains of mice with induced mutations. In 1998, our mouse bank was established in the Center for Animal Resources and Development (CARD), Institute of Resource Development and Analysis, Kumamoto University, Japan, based on the Preservation, supply and development of genetically engineered animals report published by the Ministry of Education, Culture, Sports, Science and Technology. We cryopreserve mouse embryos and sperm, supply these resources, organize training courses to educate people and form part of a domestic and international network of both mutagenesis and resource centers. We currently have over 1,500 mouse strains, 842,000 frozen embryos and 26,000 straws containing frozen sperm. Moreover, we disclose information about 1,300 deposited strains. Furthermore, over 400 strains of frozen embryos or mice produced from frozen embryos and sperm are being supplied to the requesters both domestically and internationally. Additionally we hold training courses on the cryopreservation of mouse germplasm 2~3 times a year, both domestically and internationally. In the course, we teach basic reproductive engineering techniques to trainees on a man-to-man basis. We have already held 28 training courses on the cryopreservation of mouse germplasm at our center and at other institutes.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.4
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• pp.226-230
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• 2022

The sheep can be reproduced by natural mating as well as applied reproductive biotechnology, embryo transfer (ET). However, this method in sheep is influenced by several factors such as season, photoperiod, latitude, temperature, nutrition, and breed. In addition, there is still less research on assisted reproductive technologies in small ruminants, compared to other livestock species such as cattle and pigs. Because there has been a need for an optimization and a continuous improvement of ET techniques in small ruminants. the main objective of this study was to evaluate the conception rate obtained after ET in Mongolian sheep (Dorper breed). After embryo recover, code 1 and 2 embryos (morula or blastocyst stage) for ET in the present study were 63% (63/100) and 24% (24/100), respectively. Then Each single embryo was transferred to a synchronized recipient who prepared by estrous synchronization protocol with fluorogestone acetate-cloprostenol sodium. The results demonstrated that an average conception rate and lambing rate was 35.6% (31/87) and 33.3% (29/87), respectively. Further study is still necessary, but these results indicated that single embryo of Mongolian sheep with the present protocol was enough to conducting ET when the genetically superior sheep were necessary to be expanded.

• Korean Journal of Animal Reproduction
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• v.12 no.2
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• pp.91-96
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• 1988

A study was conducted to improve breeding efficiency of dairy and beef cows on Cheju Island. Milk progesterone and plasma progesterone profiles were determined by using radioimmunoassay techniques during the oestrus cycle, onset on oestrus and during the gestation period. Progesterone connections in milk were very low during the oestrus with a means value of 2.4ng/ml and 4.6ng/ml at the onset of oestrus but gradually declined at 4 to 9 hr after oestrus. In the cyclic cow, milk progesterone concentraitons in the early part of the cycle, ranged from 3 to 5ng/ml and increased from 6.0 to 11.6ng/ml on day 13 to 21 of cycle. Milk progesterone concentrations of pregnancy cows ranged from 5.0 to 40ng/ml during the gestation and grom basal line to 3.5ng/ml for nonpregnant cows. Plasma progesterone concentrations of beef during pregnancy period ranged form 3.0 to 33ng/ml and basal levels ranged from 0 to less than 2.5ng/ml for non-pregnant beef cows.

• Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.256-267
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• 2023

The suitability of any fish species for successful aquaculture requires basic information on its reproduction and growth. This study investigated some facets of the reproductive biology of Synodontis shall (Mochokidae) from River Siluko in Nigeria. Fish samples were collected forth-nightly for a duration of fourteen (14) months-March 2015 to April, 2016 with the assistance of artisanal fishermen. Fishes were identified using taxonomic guides and standard techniques were used for determination of sex ratio, gonad maturation and fecundity. Linear regression method was used to define the correlation between fecundity and fish length, body weight and ovary weight. Results showed that sex ratio did not indicate a significant divergence (p > 0.05) from the 1 male to 1 female distribution ratio (1:1.41). Gonad morphology revealed paired gonads. Testes and ovaries were classified into four maturity stages: immature, resting, ripening and ripe. Gonadosomatic index ranged from 0.04 to 5.68 (males) and 0.03 to 20.19 (females). Absolute fecundity ranged from 1,014 to 4,520 eggs (mean = 2,592 eggs) and did not correlate significantly (p > 0.05) to ovary weight. This study has contributed to existing data on the biology of freshwater fish species in Nigeria and provided valuable information for fishery management tools in the conservation and utilization of this valuable freshwater fish species.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.7
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• pp.1071-1086
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• 2003

Reproductive biotechnologies continue to be developed for genetic improvement of both river and swamp buffalo. Although artificial insemination using frozen semen emerged some decades back, there are still considerable limitations. The major problem appears to be the lack of efficient methods for estrus detection and timely insemination. Controlled breeding experiments in the buffalo had been limited and similar to those applied in cattle. Studies on multiple ovulation and embryo transfer are essentially a replica of those in cattle, however with inherent problems such as lower number of primordial follicles on the buffalo ovary, poor fertility and seasonality of reproduction, lower population of antral follicles at all stages of the estrous cycle, poor endocrine status and a high incidence of deep atresia in ovarian follicles, the response in terms of transferable embryo recovery has remained low with 0.51 to 3.0 per donor and pregnancy rates between 15 to 30%. In vitro production of buffalo embryos is a valid alternative to recovery of embryos by superovulation. This aspect received considerable attention during the past decade, however the proportion of embryos that develops to the blastocyst stage is still around 25-30% and hence the in vitro culture procedures need substantial improvement. Embryo cryopreservation procedures for direct transfer post thaw need to be developed for bubaline embryos. Nuclear transfer and embryo cloning is a technique that has received attention in various species during recent years and can be of immense value in buffaloes as they have a low rate of embryo recoveries by both in vitro and in vivo procedures. Gender pre-selection, genome analysis, gene mapping and gene transfer are a few of the techniques that have been studied to a limited extent during recent years and are likely to be included in future studies on buffaloes. Very recently, reproductive biotechnologies have been applied to feral buffaloes as well, but the results obtained so far are modest. When fully exploited they can play an important role in the preservation of endangered species.

• Safety and Health at Work
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• v.2 no.1
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• pp.39-51
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• 2011

Objectives: This study was designed to evaluate exposure levels of various chemicals used in wafer fabrication product lines in the semiconductor industry where work-related leukemia has occurred. Methods: The research focused on 9 representative wafer fabrication bays among a total of 25 bays in a semiconductor product line. We monitored the chemical substances categorized as human carcinogens with respect to leukemia as well as harmful chemicals used in the bays and substances with hematologic and reproductive toxicities to evaluate the overall health effect for semiconductor industry workers. With respect to monitoring, active and passive sampling techniques were introduced. Eight-hour long-term and 15-minute short-term sampling was conducted for the area as well as on personal samples. Results: The results of the measurements for each substance showed that benzene, toluene, xylene, n-butyl acetate, 2-methoxy-ethanol, 2-heptanone, ethylene glycol, sulfuric acid, and phosphoric acid were non-detectable (ND) in all samples. Arsine was either "ND" or it existed only in trace form in the bay air. The maximum exposure concentration of fluorides was approximately 0.17% of the Korea occupational exposure limits, with hydrofluoric acid at about 0.2%, hydrochloric acid 0.06%, nitric acid 0.05%, isopropyl alcohol 0.4%, and phosphine at about 2%. The maximum exposure concentration of propylene glycol monomethyl ether acetate (PGMEA) was 0.0870 ppm, representing only 0.1% or less than the American Industrial Hygiene Association recommended standard (100 ppm). Conclusion: Benzene, a known human carcinogen for leukemia, and arsine, a hematologic toxin, were not detected in wafer fabrication sites in this study. Among reproductive toxic substances, n-butyl acetate was not detected, but fluorides and PGMEA existed in small amounts in the air. This investigation was focused on the air-borne chemical concentrations only in regular working conditions. Unconditional exposures during spills and/or maintenance tasks and by-product chemicals were not included. Supplementary studies might be required.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.111-117
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• 2015

Objective: In order to increase the number of mature oocytes usable for intracytoplasmic sperm injection (ICSI), we aimed to investigate the effect of co-culturing granulosa cells (GCs) on human oocyte maturation in vitro, the fertilization rate, and embryo development. Methods: A total of 133 immature oocytes were retrieved and were randomly divided into two groups; oocytes that were cultured with GCs (group A) and oocytes that were cultured without GCs (group B). After in vitro maturation, only oocytes that displayed metaphase II (MII) underwent the ICSI procedure. The maturation and fertilization rates were analyzed, as well as the frequency of embryo development. Results: The mean age of the patients, their basal levels of follicle-stimulating hormone, and the number of oocytes recovered from the patients were all comparable between the two study groups. The number of oocytes that reached MII (mature oocytes) was 59 out of 70 (84.28%) in group A, compared to 41 out of 63 (65.07%) in group B (p=0.011). No significant difference between fertilization rates was found between the two study groups (p=0.702). The embryo development rate was higher in group A (33/59, 75%) than in group B (12/41, 42.85%; p=0.006). The proportion of highest-quality embryos and the blastocyst formation rate were significantly lower in group B than in group A (p=0.003 and p<0.001, respectively). Conclusion: The findings of the current study demonstrate that culturing immature human oocytes with GCs prior to ICSI improves the maturation rate and the likelihood of embryo development.

• Clinical and Experimental Pediatrics
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• v.53 no.10
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• pp.880-885
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• 2010

Purpose: The recent trends of multiple births (MBs) conceived by assisted reproductive technology (ART) in Korea were analyzed as well as the relationship with maternal age, especially advanced maternal age. Methods: Data were obtained from the Korean Statistical Information Service and annual ART reports from the ART committee of the Korean Society of Obstetrics and Gynecology. Results: MBs increased from the early 1990s; there was a 275% increase by 2008. The number of total live births was 448,153 and MBs accounted for 10,767; the MB rate was 24.0% in 2006. Among 2,326 deliveries conceived by ART, multiple deliveries accounted for 786 (33.8%). The total number of live births with ART was 3,125 and 1,585 (50.7%) of them were MBs. During 2006, 14.7% of the entire MBs in Korea were associated with ART. The proportion of women of advanced maternal age was much higher in the ART group than in the total live birth group. Conclusion: MBs in women of advanced maternal age have been increasing in Korea with the use of ART. The results of this study showed that ART was a significant factor associated with the increase in MBs in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.3
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• pp.451-455
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• 2015

The buffalo is an important livestock resource in several countries of South Asia and the Mediterranean regions. However, reproductive efficiency is compromised due to known problems of biological and management origins, such as lack of animal selection and poor nutrition. Under optimal conditions puberty is attained at 15 to 18 months in river buffalo, 21 to 24 months in swamp buffalo and is influenced by genotype, nutrition, management and climate. However, under field conditions these values deteriorate up to a significant extant. To improve reproductive efficiency, several protocols of oestrus and ovulation synchronization have been adopted from their use in commercial cattle production. These protocols yield encouraging pregnancy rates of (30% to 50%), which are comparable to those achieved in buffaloes bred at natural oestrus. The use of sexed semen in buffalo heifers also showed promising pregnancy rates (50%) when compared with conventional non-sexed semen. Assisted reproductive technologies have been transferred and adapted to buffalo but the efficiency of these technologies are low. However, these latest technologies offer the opportunity to accelerate the genetic gain in the buffalo industry after improving the technology and reducing its cost. Most buffaloes are kept under the small holder farming system in developing countries. Hence, future research should focus on simple, adoptable and impact-oriented approaches which identify the factors determining low fertility and oestrus behaviour in this species. Furthermore, role of kisspeptin needs to be explored in buffalo.

• Clinical and Experimental Reproductive Medicine
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• v.29 no.4
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• pp.251-258
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• 2002

Objective : The aim of this study was to evaluate the outcomes of the GnRH antagonist (Cetrotide) minimal stimulation protocol comparing with GnRH agonist combined long step down stimulation protocol in PCOS patients. Materials and Method: From Apr 2001 to May 2002, 22 patients (22 cycles) were performed in controlled ovarian hyperstimulation using by GnRH antagonist and GnRH agonist for PCOS patients. GnRH antagonist (Cetrotide) combined minimal stimulation protocol was administered in 10 patients (10 cycles, Study Group) and GnRH agonist long step down stimulation protocol was administered in 12 patients (12 cycles, Control Group). We compared the pregnancy rate/cycle, total FSH (A)/cycle, Retrieved oocyte/cycle, the incidence of ovarian hyperstimulation syndrome, multiple pregnancy rate between the two groups. Student-t test were used to determine statistical significance. Statistical significance was defined as p<0.05. Results: Group of GnRH antagonist (Cetrorelix) minimal stimulation protocol produced fewer oocytes (6.4 versus 16.3 oocytes/cycle) using a lower dose of FSH (22.2 versus 36.1 Ample/cycle) and none developed OHSS and multiple pregnancy. Although the trends were in favour of the GnRH antagonist (Cetrorelix) protocol, the differences did not reach statistical significance. This was probably due to small sample size. Conclusion: The use of GnRH antagonist reduce the risk of ovarian hyperstimulation and multiple pregnancy. We suggest that GnRH antagonist might be alternative controlled ovarian hyperstimulation method, especially in PCOS patients who will be ovarian high response.