• Elastomers and Composites
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• v.37 no.4
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• pp.224-233
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• 2002

This study has investigated the flame retardant properties of EPDM rubber with the addition of various flame retardants. Carbon black, stearic acid, zinc oxide cross-linking agent were mixed with EPDM rubber to produce the base rubber E0 without the addition of flame retardants. Phosphorus flame retardant Tricrecyl phosphate(TCP) was added to E0 in 0.5, 1, 1.5, 2 phr to make E1~E4 samples and red phosphorus was added in 3, 6, 9, 12 phr to make E5~E8 samples. A flame retardant of the bromine family Decabromodiphenyloxide(DBDPO), and a chlorinated paraffin retardant of the chlorine family was added to E0 in 3, 6, 9, 12 phr to make E9~E12 and E13~E16 samples, repectively. Basic physical properties such as tensile strength, tear strength and hardness were measured for all the rubber samples with various flame retardant additions. There was no substantial differences. On the other hand, Oxygen index and UL94 were measured to study flame retardant properties. From oxygen index measurements E0 sample showed a value of 23.5%, indicating the improvement of flame retardant properties. Also from UL94 measurements, it was found that addition of red phosphorus resulted in maximum flame retardant effect. It was found that increasing the amount of addition resulted in decreasing combustion rate and improving flame retardant effect regardless of the kind of flame retardant.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.339-353
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• 1994

Background : The p53 gene codes for a DNA-binding nuclear phosphoprotein that appears to inhibit the progression of cells from the G1 to the S phase of the cell cycle. Mutations of the p53 gene are common in a wide variety of human cancers, including lung cancer. In lung cancers, point mutations of the p53 gene have been found in all histological types including approximately 45% of resected NSCLC and even more frequently in SCLC specimens. Mutant forms of the p53 protein have transforming activity and interfere with the cell-cycle regulatory function of the wild-type protein. The majority of p53 gene mutations produce proteins with altered conformation and prolonged half life; these mutant proteins accumulate in the cell nucleus and can be detected by immunohistochemical staining. But protein overexpression has been reported in the absence of mutation. p53 protein overexpression or gene mutation is reported poor prognostic factor in breast cancer, but in lung cancer, its prognostic significance is controversial. Method : We investigated the p53 abnormalities by nucleotide sequencing, polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP), and immunohistochemical staining. We correlated these results with each other and survival in 75 patients with NSCLC resected with curative intent. Overexpression of the p53 protein was studied immunohistochemically in archival paraffin- embedded tumor samples using the D07(Novocastra, U.K.) antibody. Overexpression of p53 protein was defined by the nuclear staining of greater than 25% immunopositive cells in tumors. Detection of p53 gene mutation was done by PCR-SSCP and nucleotide sequencing from the exon 5-9 of p53 gene. Result: 1) Of the 75 patients, 36%(27/75) showed p53 overexpression by immunohistochemical stain. There was no survival difference between positive and negative p53 immunostaining(overall median survival of 26 months, disease free median survival of 13 months in both groups). 2) By PCR-SSCP, 27.6%(16/58) of the patients showed mobility shift. There was no significant difference in survival according to mobility shift(overall median survival of 27 in patients without mobility shift vs 20 months in patients with mobility shift, disease free median survival of 8 months vs 10 months respectively). 3) Nucleotide sequence was analysed from 29 patients, and 34.5%(10/29) had mutant p53 sequence. Patients with the presence of gene mutations showed tendency to shortened survival compared with the patients with no mutation(overall median survival of 22 vs 27 months, disease free median survival of 10 vs 20 months), but there was no statistical significance. 4) The sensitivity and specificity of immunostain based on PCR-SSCP was 67.0%, 74.0%, and that of the PCR-SSCP based on the nucleotide sequencing was 91.8%, 96.2% respectively. The concordance rate between the immunostain and PCR-SSCP was 62.5%, and the rate between the PCR-SSCP and nucleotide sequencing was 95.3%. Conclusion : In terms of detection of p53 gene mutation, PCR-SSCP was superior to immunostaining. p53 gene abnormalities either overexpression or mutation were not a significant prognostic factor in NSCLC patients resected with curative intent. However, patients with the mutated p53 gene showed the trends of early relapse.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.47-55
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• 2005

These studies were done to know decalcification methods to reduce the time of decalcification for quick bone tissue diagnosis. When bone tissue was decalcified with 10 % formic acid at room temperature, decalcification and hematoxylin & eosin (H&E) stains were complete and satisfactory after 12 hours, but some of the tissue sections fell off during staining. In this way, decalcification, H&E stains were complete and satisfactory after 24 hours, 36 hours and 48 hours, tissue sections didn't fall off during staining. When bone tissue was decalcified with 10 % formic acid in a $60^{\circ}C$ paraffin oven, decalcification and H&E stains were complete and satisfactory after 6 hours, but some tissue sections fell off during staining. In this way, decalcification and tissue sections were complete, with no falling off during staining after 8 hours, 10 hours, 12 hours, 14 hours, 24 hours, or H&E stains were satisfactory from 8 hours to 12 hours, but H&E stains appeared to reddish nucleus after 14 hours and 24 hours. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at DECAL machine frequencies of 15 Hz and 45 Hz, and for 6 hours, 12 hours and 24 hours at a DECAL machine frequency of 90 Hz. Decalcification and H&E stains were complete and satisfactory after 6 hours at the 15 Hz and 45 Hz DECAL settings. Some of the tissue sections fell off during staining at the 15 Hz DECAL machine setting. At the 90 Hz setting, decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 4 hours. In this way, decalcification, H&E stains, and tissue section were complete and satisfactory with no falling off during staining after 12 hours, 24 hours at all machine settings. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at $37^{\circ}C$ 3 hours, 6 hours and 12 hours at $45^{\circ}C$ and 1 hours, 5 hours and 10 hours at $60^{\circ}C$ with the RHS-1 machine setting at 60Hz. At the temperatures of $37^{\circ}C$, $45^{\circ}C$, and $60^{\circ}C$ decalcification, H&E stains, and tissue sections were complete and satisfactory, with no falling off during staining except for after 6 hours at $37^{\circ}C$. 3 hours, 1 hours, or decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 12 hours and 24 hours at $37^{\circ}C$, 6 hours and 12 hours at $45^{\circ}C$, and 5 hours at $60^{\circ}C$. But H&E stains appeared to reddish nucleus after 10 hours at $60^{\circ}C$. From the above reults, the authors were able to deduce that decalcification is accelerated by heat and frequency. We therefore think that it is necessary for machines which are similar to the RHS-1 machine to be maintained at the temperature evenly with agitation effect for quick decalcification.

• Korean Journal of Veterinary Research
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• v.30 no.1
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• pp.1-8
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• 1990

The present study was focussed mainly on the morphological changes of the glandular tubules in the large intestine according to age of piglets. Samples were taken from large intesine of 1-, 10-, 20-, 35- and 45-day-old piglets, 2 to 3 piglets in each age group. The intestinal samples were fixed in 10% neutral formalin solution, dehydrated, and then paraffin sections were stained with H-E. The results observed were summarized as follows: 1. The mucosal glands in the cecum and colon tend to be unbranched simple straight tubular glands, or often two or more branched simple stright tubular glands. 2. The number of the longitudinal folds and the number of the crypts per cross section of piglet colons, respectively, were 1-day-old piglets-$3.8{\pm}0.8$, $92.1{\pm}6.9$; 10-day-old piglets-$7.1{\pm}1.1$, $164.2{\pm}10.3$; 20-day-old piglets-$15.2{\pm}0.8$, $178.5{\pm}6.8$; 35-day-old piglets-$19.3{\pm}3.0$, $454.9{\pm}25.3$; 45-day-old piglets-$20.6{\pm}3.1$, $524.6{\pm}37.2$, and the regression equation between age and these two number were $\hat{Y}=0.40X+4.32$ and $\hat{Y}=10.4X+51.52$, respectively. 3. The length and cell number per single side wall of a glandular tubule in the colon section were 1-day-old piglets-$196.3{\pm}7.1{\mu}m$, $40.0{\pm}3.3$; 10-day-old piglets-$236.0{\pm}34.5{\mu}m$, $47.9{\pm}5.3$; 20-day-old piglets-$262.8{\pm}39.6{\mu}m$, $54.3{\pm}9.0$; 35-day-old piglets-$291.75{\pm}48.3{\mu}m$, $56.9{\pm}4.9$; 45-day-old piglets-$364.8{\pm}61.5{\mu}m$, $67.7{\pm}7.4$, respectively, and the regression equation between age and these two data were $\hat{Y}=3.45X+193.8$ and $\hat{Y}=0.56X+41.0$, respectively. 4. The overall percentages of the cell number and length of glandular tubules in piglet colons were the pit and isthmus-$75.3{\pm}11.1%$, $78.8{\pm}12.3%$; gland-$24.7{\pm}5.4%$, $21.2{\pm}5.3%$, respectively. 5. The length and cell number of single side wall of glandular tubules in cecal sections were 1-day-old piglets-$190.3{\pm}31.1{\mu}m$, $37.6{\pm}4.8$; 10-day-old piglets-$235.6{\pm}25.3{\mu}m$, $46.2{\pm}3.6$; 20-day-old piglets-$295.3{\pm}45.6{\mu}m$, $52.0{\pm}6.2$; 35-day-old piglets-$351.3{\pm}28.3{\mu}m$, $60.4{\pm}8.5$; 45-day-old piglets-$366.3{\pm}48.5{\mu}m$, $64.7{\pm}8.2$, respectively, and the regression equation between age and these two data were $\hat{Y}=4.11X+196.6$ and $\hat{Y}=0.60X+38.9$, respectively.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.321-327
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• 2014

Purpose : To verify the accuracy of the Ecilpse's dose calculation algorithm(AAA:Analytic anisotropic algorithm) in case of a radiation treatment on Inhomogeneous tissues using FFF beam comparing dose distribution at TPS with actual distribution. Materials and Methods : After acquiring CT images for radiation treatment by the location of tumors and sizes using the solid water phantoms, cork and chest tumor phantom made of paraffin, we established the treatment plan for 6MV photon therapy using our radiation treatment planning system for chest SABR, Ecilpse's AAA(Analytic anisotropic algorithm). According to the completed plan, using our TrueBeam STx(Varian medical system, Palo Alto, CA), we irradiated radiation on the chest tumor phantom on which EBT2 films are inserted and evaluated the dose value of the treatment plan and that of the actual phantom on Inhomogeneous tissue. Results : The difference of the dose value between TPS and measurement at the medial target is 1.28~2.7%, and, at the side of target including inhomogeneous tissues, the difference is 2.02%~7.40% at Ant, 4.46%~14.84% at Post, 0.98%~7.12% at Rt, 1.36%~4.08% at Lt, 2.38%~4.98% at Sup, and 0.94%~3.54% at Inf. Conclusion : In this study, we discovered the possibility of dose calculation's errors caused by FFF beam's characteristics and the inhomogeneous tissues when we do SBRT for inhomogeneous tissues. SBRT which is most popular therapy method needs high accuracy because it irradiates high dose radiation in small fraction. So, it is supposed that ideal treatment is possible if we minimize the errors when planning for treatment through more study about organ's characteristics like Inhomogeneous tissues and FFF beam's characteristics.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.71-81
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• 2004

In this study, we attempt to investigate the mechanisms by which PDL cells regulate osteoclast formation and also tc know whether PDL retained their characteristic phenotype during tooth eruption and interdental separation. Rats were prepared at developmental days 21 (pre-root formation), 27(toot development), 34(advanced root formation/eruption) and at later times(adult rats). To induce severe resorption state of alveolar bone and tooth root, interdental separation with brass wire was performed between the lower first and second molars for 2 weeks in adult rats. Rat mandibles were demineralized and embedded in paraffin, and horizontal and frontal section were prepared for immuno-histochemical analysis using PDL-specific protein 22 (PDLs22), receptor activator of NFKB ligand (RANKL) and osteoprotegerin (OPG) antibodies. 1. Root formation and eruption stage of tooth development. 1) PDLs22 immunolocalization was observed in tooth follicle/PDL cells and osteoblasts throught out the root formation and eruption stages of tooth development. 2) RANKL expression became stronger at eruption stage than root formation stage of tooth development. 3) Strong expression of OPG was detected in follice/PDL cells of toot formation stage but it was decreased with tooth eruption. 2. Interdental separation between lower first and second molar 1) Comparared to normal animal, multinucleated osteoclasts and odontoclasts were markedly induced in the alveolar bone and tooth root with PDL remodeling in hematoxylin-eosin section. 2) PDLs22 expression was decreased with interdental separation. 3) RANKL expression was Increased with interdental separation in PDL fibroblasts, osteoblasts, odontoclasts and it lacunae, resorting dentin, cementum and bone matrix. 4) OPG expression was slightly decreased in the PDL cells adjacent to the alveolar bone and root surface with interdental separation. These results suggested that during tooth eruption and tooth movement, RANKL and OPG in the periodontal tissues are important determinants regulating balanced alveolar bone and tooth root resorption. And it is also suggested that PDL cells retained their characteristic phenotype during tooth eruption and interdental separation except for the short period of PDL remodeling.

• Journal of dental hygiene science
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• v.6 no.3
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• pp.159-162
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• 2006

This study examined the relationship between the quantity of Streptococcus mutans and Lactobacillus spp. related to dental caries and the degree of acidity in saliva. A total of 240 saliva samples were taken from 80 subjects at the faculty of dentistry in Skopje, Macedonia. The saliva samples were taken by stimulating saliva production stimulation with paraffin chewing. However, no stimulation was applied when obtaining the samples used for measuring the pH. The data showed that in the caries group, S. mutans in 1 ml of saliva formed colonies with confluent growth (CFU > $10^6$ and $10^4-10^5$) in 100% of samples, whereas the Lactobacillus spp. formed colonies with confluent growth in 78.3%. In contrast, no colonies with confluent growth (CFU > $10^6$ and $10^5$) were found in the control group (with healthy intact teeth). In the caries group, the pH of the saliva was slightly acidic (pH = 5.90 - 6.50) and the buffering capacity was very low (below 0.7 ml of saliva per min). On the other hand, the pH of the saliva in the control group was neutral (pH 7.01 - 7.7) and the buffering capacity was high (over 1 ml of saliva per min). The increased number of S. mutans and Lactobacillus spp. in 1 ml of saliva (above $10^5$ CFU or more) from the CRT (Caries Risk Test, Vivadent, Liechtenstein) bacteria test can indicate an increased caries risk as well as slightly higher acidity of the saliva. Overall, these results reveal that the caries risk can be predicted by simply measuring the pH and buffering capacity of saliva, and can be used to monitor the effect of dental hygiene practices with the aim of preventing dental caries.

• The Journal of Dong Guk Oriental Medicine
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• v.7 no.2
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• pp.107-120
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• 1999

Synovial joint of BALB/C mice were injeced with Lipopolysaccharide(LPS) were observed to investigate the morphological changes of synovial capsule caused by rheumatoid arthritis(RA). The RA on female Balb/c mice were induced by LPS injection, as dose of $300{\mu}{\ell}/kg$, into synovial cavity of knee joint. And then these specimen were fixed in 10% neutral buffered formalin and were decalcificated in EDTA solution for 4 weeks. The hyperplasia of synovium were appeared in synovial membrane. The filopodia of phagocytic like synoviocyte(type I synoviocyte) projected into synovial cavity and the number of fibroblast like synoviocyte(type II synoviocyte) with well-developed endoplasmic reticulum were increased in synovium. In fibrous membrane, the fibrosis induced by synthesis of collagen fiber were enlarged to all fibrous membrane, and the number of fibroblast were increased. A great number of inflammation component cell as lymphocyte and neutrophil leukocyte were infiltrated around capillary and the degranulate typed mast cell were increased. As results indicated that the hyperplasia of synovium induced by LPS, subsequently to cause the fibrosis, infiltration of imflammation component cell, and increase of degranulated type mast cell as same as symptoms of RA.

• Radiation Oncology Journal
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• v.19 no.2
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• pp.181-189
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• 2001

Purpose : Changes in the balance between MMP and TIMP can have a profound effect on the composition in the extracellular matrix (ECM) and affect various cellular functions including adhesion, migration, differentiation of cells, and fibrosis and invasion and metastasis of cancer cells. Radiation therapy is a popular treatment modality for benign and malignant tumor, but the study for radiation effect on MMP and TIMP is scarce. In the current study, we have examined the expression of TIMP in fibrosis-prone (C57BL/6) mice after radiation. Methods and Materials : Adult female mice of $10\~12$ weeks were used. The whole body were irradiated using a Varian CL-4/100 with 2 and 10 Gy. Immunohistochemical staining was peformed according to Avidin Biotin complex method and evaluated by observing high power field. For TIMP-1, TIMP-2 antibodies, reactivity was assessed in the parenchymal cell and in the stromal cell. The scale of staining was assessed by combining the quantitative and qualiative intensity of staining. Results : TIMP-1 immunoreactivity did not change in lung. But, in liver, TIMP-1 immunoreactivity was localized in cytoplasm of hepatocyte and Kupffer cell. in kidney, TIMP-1 immunoreactivity was localized in cytoplasm of some tubular cell. Temporal variations were not seen. Dose-response relationship was not seen except kidney. TIMP-2 immunoreactivity in lung was a score (++) at 0 Gy and elevated to a score (+++) at 2 Gy. TIMP-2 immunoreactivity was a score (++) in liver at 0 Gy. TIMP-2 immunoreactivity was localized in cytoplasm of hepatocyte and Kupffer cell as same as patterns of TIMP-1 immunoreactivity. The TIMP-2 immunoreactivity in liver was elevated to (+++) at 2 Gy. Immunoreactivity to TIMP-2 in kidney was a score (+++) at 0 Gy and was not changed at 10 Gy. The score of TIMP-2 immunoreactivity was reduced to (++) at 2 Gy. TIMP-2 immunoreactivity was confined to tubules in kidney. Temporal variation of TIMP-2 immunoreactivity was irregular. Dose-response relationship of TIMP-2 immunoreactivity was not seen. Conclusions : Differences between intensity of expression of TIMP-1 and TIMP-2 in each organ was present. Expression of TIMP was localized to specific cell in each organ. Irradiation increased TIMP-1 immunoreactivity in the liver and the kidney. Irradiation increased TIMP-2 immunoreactivity in the lung. But, in the liver and the kidney, TIMP-2 expression to radiation was irregular. Temporal variation of TIMP-2 immunoreactivity was irregular. Dose-response relationship of TIHP-2 immunoreactivity was not seen. In the future, we expect that the study of immunohistochemical staining of longer period of postirradiation and quantitative analysis using western blotting and northern blotting could define the role of TIMP in the radiation induced tissue fibrosis.

• Journal of Periodontal and Implant Science
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• v.29 no.3
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• pp.483-509
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• 1999

Biodegradable barrier membrane has been demonstrated to have guided bone regeneration capacity on the animal study. The purpose of this study is to evaluate the effects of cultured calvarial cell inoculated on the biodegradable barrier membrane for the regeneration of the artificial bone defect. In this experiment 35 Sprague-Dawley male rats(mean BW 150gm) were used. 30 rats were divided into 3 groups. In group I, defects were covered periosteum without membrane. In group II, defects were repaired using biodegradable barrier membrane. In group III, the defects were repaired using biodegradable barrier membrane seeded with cultured calvarial cell. Every surgical procedure were performed under the general anesthesia by using with intravenous injection of Pentobarbital sodium(30mg/Kg). After anesthesia, 5 rats were sacrificed by decapitation to obtain the calvaria for bone cell culture. Calvarial cells were cultured with Dulbecco's Modified Essential Medium contained with 10% Fetal Bovine Serum under the conventional conditions. The number of cell inoculated on the membrane were $1{\times}10^6$ Cells/ml. The membrane were inserted on the artificial bone defect after 3 days of culture. A single 3-mm diameter full-thickness artificial calvarial defect was made in each animal by using with bone trephine drill. After the every surgical intervention of animal, all of the animals were sacrificed at 1, 2, 3 weeks after surgery by using of perfusion technique. For obtaining histological section, tissues were fixed in 2.5% Glutaraldehyde (0.1M cacodylate buffer, pH 7.2) and Karnovsky's fixative solution, and decalcified with 0.1M disodium ethylene diaminetetraacetate for 3 weeks. Tissue embeding was performed in paraffin and cut parallel to the surface of calvaria. Section in 7${\mu}m$ thickness of tissue was done and stained with Hematoxylin-Eosin. All the specimens were observed under the light microscopy. The following results were obtained. 1 . During the whole period of experiment, fibrous connective tissue was revealed at 1week after surgery which meant rapid soft tissue recovery. The healing rate of defected area into new bone formation of the test group was observed more rapid tendency than other two groups. 2 . The sequence of healing rate of bone defected area was as follows ； test group, positive control, negative control group. 3 . During the experiment, an osteoclastic cell around preexisted bone was not found. New bone formation was originated from the periphery of the remaing bone wall, and gradually extended into central portion of the bone defect. 4 . The biodegradable barrier membrane was observed favorable biocompatibility during this experimental period without any other noticeable foreign body reaction. And mineralization in the newly formed osteoid tissue revealed relatively more rapid than other group since early stage of the healing process. Conclusively, the cultured bone cell inoculated onto the biodegradable barrier membrane may have an important role of regeneration of artificial bone defects of alveolar bone. This study thus demonstrates a tissue-engineering the approach to the repair of bone defects, which may have clinical applications in clinical fields of the dentistry including periodontics.