• Toxicological Research
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• v.21 no.4
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• pp.271-278
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• 2005

Reproductive and developmental toxicology is concerned with various physical or chemical agents interfering with fertility in both gender or normal growth of offsprings. Reproductive and developmental toxicology is rather a complex science, with many fields, i.e., various endpoints are involved and many different mechanisms of action. For that reason, diverse aspects must be considered when attempting to assess possible adverse health effects in the area of reproductive and developmental toxicology. The thalidomide tragedy made it clear to regulatory authorities around the world that systematic, comprehensive evaluation of the reproductive cycle was needed to adequately evaluate the potential of medicinal drugs to impair the process of reproduction or the development of embryos, fetuses, and children. International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human Use (ICH) and U.S. Food and Drug Administration (FDA) developed a guideline to assess the reproductive and developmental toxicity. Also these guidelines have since been applied to the detection and regulation of environmental toxicants, food additives, and so on. Although it was hoped that testing procedures of guideline would be updated constantly to reflect the current state of the science in reproductive and developmental toxicology, it was not until this decade that regulatory guidelines and testing methods have been altered in a significant way. In this paper, we would like to present the recommended approaches and recent trends for improvement of testing guidelines or experimental methods in reproductive and developmental toxicology.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.630-636
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• 2014

To investigate the characteristics of hybrid eggs and larva produced by olive flounder Paralichthys olivaceus females and starry flounder Platichthys stellatus males, we examined the developmental speed of hybrid eggs at different water temperatures. The developmental speed of hybrid eggs tended to increase with increasing water temperature. Specifically, the hatching times were 91 hrs, 62 hrs and 43 hrs at $10^{\circ}C$, $15^{\circ}C$ and $20^{\circ}C$, respectively. The mean biological minimum temperature of the hybrid was $1.3^{\circ}C$, which is in between that of the olive flounder and the starry flounder. In high water temperatureseasons, slower growth was observed in hybrids of the starry flounder which is a coldwater fish.

• Journal of Environmental Health Sciences
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• v.46 no.4
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• pp.368-375
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• 2020

Objectives: Some animal studies have reported that methyl mercury causes developmental toxicities such as placental and fetal weight loss, but the mechanism is still unclear. This study aimed to investigate the developmental toxicities of methyl mercury, focusing on placental endocrine function and fetal growth retardation in rats. Methods: Positively same-time-mated female Sprague-Dawley rats were purchased on gestational day (GD) eight and treated with 0, 5, 10 and 20 ppm of methyl mercury (n=5) dissolved in tap water from GD eight through 19. During treatment, the drinking water (methyl mercury) intake and body weight of each pregnant rat was measured daily. On day 19, caesarean sections were performed and blood samples were collected. Developmental data such as placental and fetal weights, fetus numbers, and placental efficiency (fetal weight/placental weight) were also collected. Placental prolactin-growth hormone (PRL-GH) family, such as placental lactogen (PL) -Iv, II, and prolactin-like protein (PLP) -B, levels in serum were analyzed by ELISA. Also, placental tissues were assigned to histochemistry. Results: The mean cumulative methyl mercury exposure for the 5, 10, and 20 ppm groups were 2.37, 4.63, and 9.66 mg, respectively. The mean daily exposure of the 5, 10, and 20 ppm groups were 0.24, 0.47, and 0.97 mg, respectively. Maternal body weight increased in accordance with GD. There was no significant difference in weight gain among the experimental groups. Histopathologic changes were not observed in placental tissues among the experimental groups. However, mean placental and fetal weights were lower in the 10 and 20 ppm exposed groups compared to the control. Placental efficiency was also lower in the 10 and 20 ppm exposed groups compared to the control. Serum PL-Iv and II levels were lower in the 10 and 20 ppm exposed groups than the control, in accordance with the changing pattern of placental and fetal weights and placental efficiency. Conclusion: The inhibitory effects of methyl mercury on the serum levels of placental PRL-GH family such as PL-Iv and II may be secondary leads to the reduction of placental efficiency and fetal growth retardation in rats.

• Journal of Korean Academy of Nursing
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• v.29 no.6
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• pp.1445-1454
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• 1999

This study was designed to investigate the effects of a sensory stimulation program on the growth (weight, height, head circumference, and chest circumference), behavioral development, behavioral states, and the heart rate of the infants. A total of 23 infants of 2 weeks old were divided into sensory stimualtion group (11 infants) and control group (12 infants). The infants of sensory stimulation group had received sensory stimulation for 6 weeks. Sensory stimulation program was composed of tactile and kinesthetic stimulation. We assessed growth, behavioral state and heart rate every week and behavioral development every 2 weeks. The results were as follows: 1. Body weight in sensory stimulation group, from two weeks after the sensory stimulation program, was significantly increased more than control group, but there was no significant difference in height, head circumference, and chest circumference between the two groups. 2. Behavioral developmental score of sensory stimulation group was significantly higher than that of control group from two weeks after the sensory stimulation program. Developmental states of sensory stimulation group showed more 'high average developmental state' than the control group from 4 weeks after sensory stimulation program. 3. Behavioral states of sensory stimulation group after the sensory stimulation program, the 'sleeping state' was significantly increased more than control group. The 'awakening state' and the state of fuss or crying were significantly less than those of the control group. 4. The heart rate of the sensory stimulation group after the sensory stimulation was significantly lower than the control group. These results indicate that the sensory stimulation program decreases heart rate and improves the sleeping state to be effective on promoting the growth and development of the infants. In view of these experiments, we suggest sensory stimulation program might be considered as a nursing intervention for growth and development of the infants not only in clinical settings but also at homes and in the communities.

• The korean journal of orthodontics
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• v.22 no.3 s.38
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• pp.603-615
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• 1992

This study was undertaken to investigate the interrelationship between the growth change of mandible and the developmental age of growing girls in the longitudinal data from 7 years to 15 years. The data were obtained from maturation stage of cervical vertebrae through the serial lateral cephalogram, height increment records which was taken at one year interval, menarche date through interview. On the basis of findings of this study, the following conclusions were obtained. 1. In general the growth of mandible (Ar-Pog, Ar-Go, Go-Pog) showed two peaks of growth velocity. 2. The maximum growth of mandible (Ar-Pog, Ar-Go, Go-Pog) almost appeared between stage 3 and stage 4 in maturation of cervical vertebrae. 3. It showed the tendency that the maximum increment of height appeared faster than that of mandible (Ar-Pog, Ar-Go, Pog-Go). 4. The maximum growth of height almost appeared between stage 2 and stage 3 in maturation of cervical vertebrae. 5. It showed the tendency that the menarche appeared later than the maximum growth of mandible (Ar-Pog, Ar-Go, Pog-Go). 6. The menarche almost appeared at stage 4, stage 5 in maturation of cervical vertebrae.

• Applied Microscopy
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• v.43 no.1
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• pp.27-33
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• 2013

Inflammatory cells express the inflammatory cytokines and growth factors induced by lipopolysaccharide (LPS). Odontoblasts are located at the pulp-dentin interface and extend their cell processes far into the dentin where they are the first cells to encounter microorganisms or their products. Therefore, this study examined the expression of some growth factors related to the signal pathway, such as growth factor receptor binding protein 2 (Grb2)-Ras in odontoblast-like dental pulp cells, after a treatment with LPS. After 60 minutes, the mRNA and protein expression levels of Grb2 and Ras were higher in the LPS-treated cells than in the control cells. The level of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) mRNA expression was increased significantly to a level similar to that of Grb2 and Ras at 60 minutes. The platelet-derived growth factor-AA (PDGF-AA) mRNA level was expressed strongly in the odontoblast like dental pulp cells without an association with LPS stimulation. Scanning electron microscopy revealed many extensions of the cytoplasmic processes and the number of processes increased gradually at 30, 60 and 90 minutes after LPS stimulation. From these results VEGF and bFGF expression might be induced through the Grb2-Ras signal transduction pathway in LPS treated odontoblasts.

• Development and Reproduction
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• v.15 no.1
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• pp.9-15
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• 2011

The population growth and reproduction of Tetrahymena pyriformis were studied under shaken (aerobic) and unshaken (anaerobic) conditions by applying the growth models, exponential and logistic growth models and the population growth of Tetrahymena was showed the logistic growth model under both, shaken and unshaken conditions and also, the more oxygenated samples had greater population size (N) and three times faster growth rate (r) than less oxygenated samples during incubation periods.

• Child Health Nursing Research
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• v.8 no.3
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• pp.302-312
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• 2002

This descriptive exploratory study was conducted to analyze the results of developmental screening test using DDST and the follow-up diagnostic evaluation in one public health center, and to evaluate the feasibility of developmental screening in nursing. Samples were 373 children under 6 years who visited the public health center. Mothers' satisfaction on the developmental clinic was also determined. Summaries of the results were as follows:v 1. 0.5% of children in height and 1.9% of children in weight were included in below 3 percentile of Korean children's growth chart, but none of them showed developmental delay. 2. The results of DDST showed 92.1% of subjects were classified as normal, 3.7% as abnormal, and 4.2% as questionable among 354 children. 3. Most of children who showed the abnormal development at the first DDST were confirmed having the developmental delay at the follow-up diagnostic evaluation. On the other hand, most of children who showed the questionable development at the first DDST revealed having the normal development in follow-up screening test. 4. The result of the DDST was influenced by the birth order of the subject and delivery type. 5.The mean satisfaction score by mothers on developmental clinic was 4.35 in 5 Likert scale. In conclusion, we could certain the feasibility and usefulness of developmental screening in community and child care nursing. To fulfil the increasing needs of mothers with infants on the child development, nurses have to provide anticipatory guidance and parent education in addition to the developmental screening test. We hope to expand the developmental screening in nursing field not only of clinical setting but also of community.

• Journal of Korean Academy of Nursing
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• v.13 no.3
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• pp.51-60
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• 1983

Currently changing trends of child health care is demand total health assessment of child including growth and development. This study concentrates on the growth & developmental status of low birth weight infant for help their growth & development. Thus it can be provide a direction for scientific health education and counseling materials by investigating factor of growth & development. The subjects for this study were made up of 40 low birth weight infant who attended the well baby clinic of E university Hospital. The study method used was a questionnaire ＆ anthropometric assessment and DDST for normative data of development. The period for data collection was from July 1st to August 31th, 1982. Analysis of the data was done using percentages, $\chi$$^2$-test Stepwise Multiple Regression. The results of study were as follows. 1. The mean weight of birth was 2,068gm and mean of gestational period was 35.65 weeks. 2. The age at which weight ; 32.5%, head circumference : 67,5% chest circumference : 55.0%, height : 50. 0％ was normal range of physical growth. 3. The reverse age at which social development ; 87.5%, fine motor & adaptive development ; 70.0%, gross motor development ; 72.5% of children Passed by DDST to determine of normal range of development. 4. In the among variables, it was found that the infant who were the higher emotional & verbal response of mother and stimulus environment was the more normal range of weight & development than who was not. 5. The stepwise Multiple Regression between developmental status and predictors-birth order, weight at birth, sex, antenatal care, gestational period-are accounts for 34.1%.

• Development and Reproduction
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• v.16 no.4
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• pp.329-338
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• 2012

The proliferation of embryonic cells or adult stem cells in tissue is critically regulated during development and repair. How limited the proliferation of cells, so far, is not much explored. Cell-cell contact proliferation inhibition is known as a crucial mechanism regulating cell proliferation in vitro and in vivo. In this study we examined the characters of mouse subcutaneous adipose derived stem cells (msADSC) whether they lost or get contact inhibition during in vitro culture. The characters of msADSC growth after confluence were analyzed using confocal microscope and the expression profiles of contact inhibition related genes were analyzed according to the morphological changes using real-time PCR method. msADSC showed overlapping growth between them but not after passage 14. The cell shapes were also changed after passage 14. The expression profiles of genes which are involved in contact inhibition were modified in the msADSC after passage 14. The differentiation ability of msADSCs to adipocyte, chondrocyte and osteocyte was not changed by such changes of gene expression profiles. Based on these results, it is revealed that smADSC were characterized by getting of strong cell-cell contact inhibition after passage 14 but the proliferation and developmental ability were not blocked by the change of cell-cell contact proliferation inhibition. These finding will help to understand the growth of adipose tissue, although further studies are needed to evaluate the physiological meaning of the cell-cell contact proliferation inhibition during in vitro culture of msADSC.