• Journal of electromagnetic engineering and science
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• v.6 no.1
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• pp.47-52
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• 2006

The objective of this study is to evaluate the effects of size and permittivity on the specific absorption rate(SAR) values of rat brains during microwave exposure at mobile phone frequency bands. A finite difference time domain (FDTD) technique with perfect matching layer(PML) absorbing boundaries is used for this evaluation process. A color coded digital image of the Sprague Dawley(SD) rat based on magnetic resonance imaging(MRI) is used in FDTD calculation with appropriate permittivity values corresponding to different tissues for 3, 4, 7, and 10 week old rats. This study is comprised of three major parts. First, the rat model structure is scaled uniformly, i.e., the rat size is increased without change in permittivity. The simulated SAR values are compared with other experimental and numerical results. Second, the effect of permittivity on SAR values is examined by simulating the microwave exposure on rat brains with various permittivity values for a fixed rat size. Finally, the SAR distributions in depth, and the brain-averaged SAR and brain 1 voxel peak SAR values are computed during the microwave exposure on a rat model structure when both size and permittivity have varied corresponding to different ages ranging from 3 to 10 weeks. At 900 MHz, the simulation results show that the brain-averaged SAR values decreased by about 54 % for size variation from the 3 week to the 10 week-old rat model, while the SAR values decreased only by about 16 % for permittivity variation. It is found that the brain averaged SAR values decreased by about 63 % when the variations in size and permittivity are taken together. At 1,800 MHz, the brain-averaged SAR value is decreased by 200 % for size variation, 9.7 % for permittivity variation, and 207 % for both size and permittivity variations.

• Korean Journal of Pharmacognosy
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• v.15 no.1
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• pp.24-29
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• 1984

It was previously reported from our laboratory that the rate of deterioration of contractile force was slower in the heart of the ginseng extract treated rats. It was also found that ginseng may have an ability to sustain the normal function of the heart by sustaining Ca accumulation by sarcoplasmic reticulum. $Ca^{++}-dependent$ ATPase plays the central role in movement of $Ca^{++}$ ion from sarcoplasm into sarcoplasmic reticulum. In this investigation, the fragment of sarcoplasmic reticulum was prepared from rat heart treated with ginseng water extract orally 100mg/kg/day for 7 to 10 days and from normal rat heart. $Ca^{++}-dependent$ APTase activity was estimated by a modified method of Fiske and Subbarow's procedure. Experimental groups were divided into 6 groups, depending on the preincubation time, 5, 30 and 60min. at ${25}^{\circ}C$ and ${37}^{\circ}C$ respectively. In both of the groups of ${25}^{\circ}C$ and ${37}^{\circ}C$, $Ca^{++}-dependent$ ATPase activities of the ginseng treated rat hearts were higher than that of normal hearts. Therefore, it can be concluded that $Ca^{++}-dependent$ ATPase activities in sarcoplasmic reticulum of rat hearts were increased by the treatment with ginseng extract.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.4
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• pp.1009-1013
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• 2006

The fallowing are the result of the experimental studies of KH-304 on the penile nitric oxide synthase (NOS) activity, SOD and the level of blood testosterone in old rat. KH-304 was tested for the expression and activity of eNOS, nNOS, SOD/Mn, caveol in-1, 3 in penis of old-rat. The penile expression level of the five enzyme were increased significantly after oral administration of the KH-304 100mg/kg for 100ays and the concentration of testosterone in the blood were increased. In vitro, the effect of SOD and free radical scavenging were increased significantly. Conclusively, KH-304 is capable of improving of sexual ability in old-rat.

• The korean journal of orthodontics
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• v.18 no.2
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• pp.435-447
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• 1988

This study was performed to evaluate the effect of low-power laser irradiation on the periodontium of the orthodontically moved tooth of rat. The experimental materials were 30 male rats. Orthodontic appliances were placed bilaterally between maxillary first molar and incisor teeth and the force was 1 Oz. Experimental animals were divided into eight groups as follows: no movement, 1st, 2nd, 3rd, 5th, 7th, 14th, and 28th day groups. In all experimental animals except no movement group, low-power laser was irradiated on the unilateral maxillary first molar (experimental side), but on the contralateral side, only orthodontic force was applied (control side). The histologic effects of laser on the periodontium of the orthodontically moved tooth on the consecutive experimental days were as follows: In the experimental side, by the biostimulating effect of laser, 1. Hyalinized tissue was formed later and eliminated earlier than in the control side. 2. Undermining bone resorption was occurred earlier than in the control side. 3. More osteoid tissue was deposited and calcified earlier than in the control side. 4. The most prominent changes were formation of new blood vessels and dilatation of old blood vessels.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.139-148
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• 1990

The purpose of this study was to investigate the effects of irradiation on the rat submandibular gland which composed of the epithelial growth factors. The experimental animals were the Sprague Dawley strain rats, which were the rats as the non-irradiated control group and the rats as the experimental group which were divided into groups as the experimental duration of 1 hour, 3 hours, 6 hours, 12 hours, 1 day, 3 days, 1 week, 2 weeks, 4 weeks. The experimental animals were singly irradiated at a dose of 8 Gray gamma ray to their head and neck region by the Co-60 teletherapy unit and sacrificed after each experimental duration. The specimens were stained with H-E and Azan stain and examined light microscopically. The results of this study were obtained as follows. 1. The all of mucous and serous acini in submandibular gland showed similar pattern of changes in structure according to the lapse of time. 2. The acinic cells started to change after 1 hour, and repaired after 12hours with mitosis and proliferation of the cells between acini. The changes were marked after 1day, and repaired gradually in course of time. 3. The duct were dilatated irregularly, and the outline of the eosinophilic stained ductal cells changed indistinctly.

• The Journal of Internal Korean Medicine
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• v.30 no.2
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• pp.327-337
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• 2009

Objective : In benign prostatic hyperplasia, dihydrotestosterone acts as a potent cellular androgen and promotes prostate growth. Inhibiting enzyme 5${\alpha}$-reductase, which is involved in the conversion of testosterone to the active form dihydrotestosterone, reduces excessive prostate growth. Recently Scutellaria baicalensis has been related reports about the effect of baicalein on anti-proliferation of the prostate gland. In this study, we investigated the effects of Scutellaria baicalensis on cytopathological alterations and expression of 5${\alpha}$-reductase in the rat model of benign prostatic hyperplasia induced by castration and testosterone treatment. Methods : Sprague-Dawley rat were treated with testosterone after castration for induction of experimental benign prostatic hyperplasia, which is similar to human benign prostatic hyperplasia in histopathological profiles. Scutellaria baicalensis as an experimental specimen, and finasteride as a positive control, were administered orally. The prostates were evaluated by histopathological changes, testosterone levels, and the expression of 5${\alpha}$-reductase genes. Results : While prostates of control rats revealed severe acinar gland atrophy and stromal proliferation, the rats treated with Scutellaria baicalensis showed a diminished range of tissue damage. In the reverse transcription-polymerase chain reaction(RT-PCR) of 5${\alpha}$-reductase genes. Scutellaria baicalensis inhibited the expression of 5${\alpha}$-reductase genes. Conclusions : These findings suggest that Scutellaria baicalensis may protect glandular epithelial cells and also inhibit stromal proliferation in association with the suppression of 5${\alpha}$-reductase. From theses results, we suggest that Scutellaria baicalensis could be a useful remedy agent for treating benign prostatic hyperplasia.

• Toxicological Research
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• v.12 no.2
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• pp.213-221
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• 1996

In order to develop a suitable secondary renal disease model and diagnostic markers of renal disease in the rat, the change of PIIIP (aminoterminal procollagen III peptide) in serum and hydroxyproline levels in the renal tissue that reflect the synthesis of extracellular matrix (ECM) during development of experimental renal diseases were observed. Two types of experimental primary diseases, diabetes mellitus administrated by streptozotocin (STZ, 75 mg/kg, i.p.) and liver cirrhosis produced by bile duct ligation/scission (BDL/s) operation, were induced. The hydroxyproline level increased according to the high PIIIP and NCl(carboxyterminal procollagen IV peptide) in Western blot analysis as early as 1 week in the STZ treated-rat kidney. Increased renal ECM was observed at 15 weeks in STZ and BDL/s model under the microscopic examination. High PAS positive reaction was found in capillary basement membrane in STZ treated-rats and mesangium in BDL/s operated rats at this time, showing the histological characteristics of diabetic nephropathy and cirrhotic glomerulonephritis in human, respectively. Such secondary renal failure were supported by additional tests including urinalysis and renal function test. The serum PIIIP detected by ELISA was a useful parameter to estimate synthesis rate of renal ECM during development of renal disease without extrarenal fibrosis i.e. liver cirrhosis in rats. This study is proposed that STZ treatment or BDL/s operation may be a suitable experimental animal model for the induction and development of chronic secondary renal diseases. Morover, it was found that hydroxyproline level in renal tissues was a good parameter of the change of renal ECM at the early stage of the diseases without apparent histological changes. Especially, serum PIIIP could be a choice as a diagnostic or prognostic marker during the development of renal diseases in rats.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.70-75
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• 2000

This study was undertaken to find out the effect of lead on histopathological changes in rat. Thirty female Wistar rats, 7 weeks old, were divided into a control and two experimental groups. The control was received normal diet. The two experimental groups were received diets contaminated artificially with 10 or 5,000 ug/g of lead administration group, histopathological changes were observed in the kidney, liver, heat, brain and lung from the 4th week of experiment. Desquamation of renal epithelia and inclusion bodies in the epithelia of renal tubules were demonstrated in the kidneys. But the liver did not show acid-fast inclusion body. Degeneration of cardiac muscles were seen. The number of mast cells were increased in the cardiac muscles. Darkly stained neurons in the cerebral cortex, some inflammatory cells around meningeal vessels and distended Virchow-Robin spaces were observed.

• Journal of the Korean Home Economics Association
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• v.18 no.4
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• pp.103-107
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• 1980

This study was conducted to compare the effect of dietary sucrose and starch on the lipid metabolism of Rat fed by low protein diet for 3 and 6 weeks periods. Forty male weanling Spargue-Dawley rats weighing 52.7 grams each, after being adopted for 2 days with standard diet, were blocked into 8 groups and fed experimental diet as designed. Experimental diet were composed of two different levels of proteins, 6% designed as low protein diet and 15% designed as standard protein diet. In each group, the content of serum lipid, serum cholesterol and liver lipid were measured. The results of this experiment were summerized as follows. 1. liver lipid content was tended to be high in the sucrose group of low protein fed animal. 2. the content of total serum lipid was tended to be high in the sucrose group, and this tendency was showed statistical significance in the animals fed by low and standard protein after 6 weeks of experimental period. 3. The difference in the total serum cholesterol content between the sucrose and starch group was not significant

• Toxicological Research
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• v.7 no.1
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• pp.93-112
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• 1991

This study was carried out to investigate the various factors on induction of experimental hepatocarcinogenesis in Sprauge-Dawley rats. The experimental animals were divided into three Experiment. Experiment I, II and III were began rats with initial age of 6, 16 and 55 weeks, respectively. All Experiment were injected intrapertioneal with diethylnitrosamine (DENA` 200 mg/kg) as an intiator and group 3, 4 of Experiment I, II and III were fed on diet containing 0.02% 2-acetylaminofluorene (2-AFF) as a promoter for 6 weeks. Three weeks after two-thirds partial hepatectomy was performed in group 2, 4 of Experiment I & II and group 3 of Experiment III.