• Toxicological Research
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• v.17 no.1
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• pp.11-15
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• 2001

This study was carried out to evaluate the irritant potential of A mouthwash in hamster cheek pouch. The test substances were applied twice daily to right pouches of hamsters for 14 consecutive days. Animals were administered with A mouthwash, Listerine, saline and control solution, respectively. In order to evaluate the irritant potential in mucosa of hamster cheek pouch, we observed clinical signs, mortality, body weight changes and gross and histopathological findings for 14 days. In all groups, there were neither dead animals nor significant changes of body weights. In addition, there were no differences between saline and A mouthwash treated group in gross and histopathological findings. Therefore, these results suggest that there was no irritant potential of A mouthwash in hamster cheek pouch.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.111-116
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• 2001

This study was carried out to evaluate the irritant potential of P-toothpaste in hamster cheek pouch. The test materials were applied once at the beginning of this study into right pouches of hamsters and maintained for 14 days. Animals were administered with P-toothpaste, Bamboo salt toothpaste, D.W. and control solution, respectively. In order to evaluate the irritant potential in mucosa of hamster cheek pouch, we observed clinical signs, morality, body weights and gross and histopathological findings for 14 days. In all groups, there were neither dead animals nor significant changes of body weights. In addition, there were no differences between D.W. and P-toothpaste treated group in gross and histopathological findings. Therefore, these results suggest that there was little irritant potential of P-toothpaste in hamster cheek pouch.

• Journal of Life Science
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• v.10 no.6
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• pp.605-609
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• 2000

In order to evaluate the safety of hydroxyapatite sinter produced from tuna bone in Syrian hamsters, oral mucous membrane irritation test was carried out. Oral mucous membrane irritation test was infected in Syrian hamsters as dose of 5 g/kg BW with hydroxyapatite sinder under pentobarbital sodium anesthesia. Each animal`s left cheek pouch was everted, and the samples were loosely placed at the bottom of the pouch with a double-suture technique for 14 days. Hamsters of control group were treated without inserting the hydroxylapatite sinter. Any abnormal clinical signs in both cheek pouches of control and treatment group were not observed for 14 days. There were no significant differences in body weight changes between hamsters of control and treatment group. Therefore, it suggest that hydroxyapatite sinter produced from tuna bone has no particular changes of oral mucous membrane irritation in Syrian hamsters.

• Journal of Environmental Health Sciences
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• v.41 no.6
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• pp.405-411
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• 2015

Objectives: The purpose of this study is to evaluate the optimum conditions for oral mucosal irritation testing using the buccal pouch of hamsters. Methods: Test materials were applied to the buccal pouch of seven-week old male Syrian hamsters (SLC, Japan) four times at one-hour intervals and macroscopic changes were examined at 24 hours after final treatment. After sacrifice, the buccal pouches were removed and prepared for histopathological evaluation. In order to set the exposure time, we performed exposure tests of 5, 12, 18 and 23 minutes using sodium lauryl sulfate (SLS) 1% and set the treatment volume from the test results at 2, 3, or 4 ml treatment using SLS 1%, Triton X-100 1% and ethanol. After setting the experimental conditions, seven groups of materials [sodium lauryl sulfate (SLS) (1%), Triton X-100 (1%), hydrogen peroxide (3%), ethanol (100%), chlorhexidine (0.2%, 2%), phosphate buffer saline (PBS)] were assessed. Results: Experimental conditions of material exposure time were fixed as 18 minutes from the exposure tests of 5, 12, 18 or 23 min using sodium lauryl sulfate (SLS) 1%. Treated volume was set as 4 ml per each pouch from the test results of 2, 3, or 4 ml treatments using SLS 1%, Triton X-100 1% and ethanol. The results in terms of irritation degree were in the order of sodium lauryl sulfate (SLS) (1%) > Triton X-100 (1%) ${\fallingdotseq}$ hydrogen peroxide (3%) > ethanol (100%) ${\fallingdotseq}$ chlorhexidine (0.2%, 2%) > phosphate buffer saline (PBS). Conclusion: From this study, suitable conditions for hamster mucosal irritation testing were suggested and this method was verified through materials commonly used on oral mucosal membranes.

• Toxicological Research
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• v.17 no.3
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• pp.167-171
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• 2001

Oral mucous membrane test using Syrian hamsters was performed to evaluate the reliability as a model system for the assessment of the potentially irritating substances intended for the mucous membranes, and to determine the irritating potential of a new emulsion-type formulated toothpaste. After test substances were implanted into the cheek pouches of hamsters with diluents (20 mg/kg) under pento-barbital sodium anesthesia, we made the comparison in irritation between emulsion-type and dispersion-type of triclosan (TCS) formulations in the range of 0.2% to 0.3%. The emulsion-type formulations using non-ionic surfactant showed less mucosal lesion than other commercial toothpastes with 0.3% TCS, or dispersion-type ones. However, no significant difference in irritation was detected between 0.2% and 0.3% TCS. We report that this hamster cheek pouch method could be a reliable approach for the evaluation slight difference in the irritating potentials of cosmetics and hygiene products intended for the lips or other mucous membranes, and this method showed that the new emulsion-type formulation significantly lowered the TCS-induced toxicity, compared with other commercial toothpastes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.6
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• pp.581-590
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• 2000

Alterations in the cellular genome affecting the expression or function of genes controlling cell growth and differentiation are considered to be the main cause of cancer. Over 30 oncogenes can be activated by insertional mutagenesis, single point mutations, chromosomal translocations and gene amplification. The ras oncogenes have been detected in $15{\sim}20%$ of human tumors that include some of the most common forms of human neoplasia and are known to acquire their transforming properties by single point mutations in two domains of their coding sequences, most commonly in codons 12 and 61. The ras gene family consists of three functional genes, N-ras, K-ras and H-ras which encode highly similar proteins of 188 or 189 amino acid residues generically known as P21. ras proteins have been shown to bind GTP and GTP, and possess intrinsic GTPase activity. Experimental study was performed to observe the mutational change of the ras gene family and apply the results to the clinical activity. 36 Golden Syrian Hamster each weighing $60{\sim}80g$ were used and painted with 0.5% DMBA by 3 times weekly on the right buccal cheek(experimental side) for 6, 8, 10, 12, 14 and 16 weeks. Left buccal cheek (control side) was treated with mineral oil as the same manner of the right side. The hamsters were sacrificed on the 6, 8, 10, 12, 14 & 16 weeks. Normal and tumor tissues from paraffin block were completely dissected by microdissection and DNA from both tissue were isolated by proteinase K/phenol/chloroform extraction. Segments of the K-ras and H-ras gene were amplified by PCR using the oligonucleotide primers corresponding to the homologous region (codon 12 and 61) of the hamster gene, and then confirmational change of ras genes was observed by SSCP and autosequencing analysis. The results were as follows : 1. Malignant lesion could be found in the experimental side from the experimental six weeks. 2. One hamster among six showed point mutation of the H-ras codon 12($G{\rightarrow}A$ transition) at the experimental 10 and 14 weeks. 3. One of six at 6 weeks, two of six at 8 weeks and one of six at 12 weeks revealed the confirmational change of the H-ras codon 61($A{\rightarrow}T$ transversion). 4. The incidence of point mutation of H-ras codon 12 and 61 were 5.5%(2 of 36) and 11%(4 of 36) respectively. 5. Point mutation of the K-ras could not be seen during the whole experimental period. Form the above results, these findings strongly support the concept that H-ras oncogenes may have the influence of the DMBA induced carcinoma of hamster buccal pouch.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.137-145
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• 2000

Carcinogenesis is a multi-stage process that generally consists of at least three steps; initiation, promotion, and progression. If one of these carcinogenic steps were suppressed or delayed, the cancer could be prevented. Cancer chemoprevention is defined to be inhibition or reversal of the carcinogenic process by the specific chemical agents and is a novel approach to cancer management alternative to conventional chemotherapy. Chlorophylln(CHL), a water-soluble derivative of chlorophyll, containing sodium and copper, has been known to be strong antimutagen in several test systems, but its mechanism of antimutagenic action is unknown. In the present experiment, the possibility of CHL as chemopreventive drugs on 7,12-dimethylbenz[a]anthracene(DMBA)-induced hamster buccal pouch carcinogenesis was investigated by mutagenicity test, carcinogenicity test, and frequency or spectrum of H-ras mutations in the both of DMBA-induced and chlorophylln-pretreated-DMBA induced tumor by polymerase chain reaction and non-isotopic restriction fragment length polymorphism. The treatment of CHL reduced the yields and multiplicity of the 0.5% DMBA-induced tumor, 86% to 62.5% and $3.7{\pm}0.6$ to $1.4{\pm}0.3$, respectively. The occurrence of histidine revertant by $20{\mu}mole$ DMBA was inhibited 25.6 to 81.7% by 1 to $5{\mu}M$ CHL in a dose-dependent manner. The mutation rates of H-ras gene in DMBA-induced and CHL-pretreated-DMBA induced tumor were 96%, 94% of which the most mutations were in codon 12/13. These results suggest that CHL inhibits the carcinogenic action of DMBA by the formation of complex between CHL and DMBA or the inhibition of the activation of DMBA in vivo. But CHL did not affect the mutation rates or its spectrum in already formed tumor.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3527-3531
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• 2016

Recombinant human bone morphogenetic protein-2 (rhBMP-2 ), a member of the TGF-${\beta}$ family, has been used widely in recent years to regenerate defects of the maxillary and mandible bones. Such defects are sometimes caused by resection of oral squamous cell carcinoma (OSCC) yet the biologic effects of rhBMP-2 on these carcinomas are not fully clear. The objective of this study was to determine histologically whether rhBMP-2 produces adverse effects on angiogenesis during induction of OSCC, a biologic process critical for tumor formation in an experimental model in the buccal pouch of golden Syrian hamsters. Buccal cavities were exposed to painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks, then biopsies were taken. Division was into 2 groups: a study group of 10 hamsters receiving $0.25{\mu}g/ml$ of rhBMP-2 in the $3^{rd}$ and $6^{th}$ weeks; and a control group of 10 hamsters which did not receive any additional treatment. VEGF expression and microvessel density were measured but no differences were noted between the two groups. According to this study, rh-BMP-2 does not stimulate angiogenesis during induction of OCSSs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.5
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• pp.373-384
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• 2001

Cellular proliferation is an intricately regulated process mediated by the coordinated interactions of critical growth control genes. Two of these factors in mammalian cells are the p53 and mdm-2 genes. A protein product of the mem-2 oncogene has been recently shown to associate with the protein encoded by the tumor suppressor gene p53. The p53 tumor suppressor protein is stabilized in response to DNA damage and other stress signals and causes the cell to undergo growth arrest or apoptosis, thus preventing the establishment of mutations in future cellular generations. Mutation or loss of p53 is a very common event in tumor progression. It occurs in about 50% of all tumors analysed including of colon, lung, breast and liver. The cellular mdm-2 gene, which has potential transforming activity that can be activated by overexpression, is amplified in a significant percentage of human sarcoma and in other mammalian tumors. Proteins encoded by the mdm-2 gene are able to bind to the p53 protein and, when overexpressed, can inhibit p53's transcriptional activation function, thus mdm-2 can act as a negative regulator of p53 function. Experimental study was performed to observe the relationship between p53 gene mutation and mdm-2 protein expression and apply the results to the clinical activity. 36 golden syrian hamster each weighing $60{\sim}80g$ were used and painted with 0.5% DMBA by 3 times weekly on the right buccal cheek(experimental side) for 6, 8, 10, 12, 14 and 16 weeks. Left buccal cheek(control side) was treated with mineral oil as the same manner to the right side. The hamsters were sacrificed on the 6, 8, 10, 12, 14 & 16 weeks. Normal and tumor tissues from paraffin block were examined for histology and immunohistochemistry observation, and were completely dissected by microdissection and DNA from both tissue were isolated by proteins K/phenol/chloroform extraction. Segments of the hamster p53 exons 5, 6, 7 and 8 were amplified by PCR using the oligonucleotide primers, and then confirmational change was observed by SSCP respectively. The results were as follows : 1. Dysplasia at 6 weeks, carcinoma in situ at 8 weeks and invasive carcinoma from 10 weeks could be observed in experimental groups. 2. p53 mutations were detected in 10 of the 36(28%) and the exons 6(6 of the 10 : 60%) was the most hot spot area among the highy conserved region(exons 5, 6, 7 & 8). 3. Immunohistochemical study confirmed 22 of the 36(61%) of p53 expression involving 10 of p53 mutations. 4. mdm-2 expression of was showed in 3 of the 36(8%) involving 1 of the 22 of p53 expression and 2 of the 14 of p53 non-expression. From the above results, mutation of p53 gene or expression of p53 protein may have the influence of the DMBA induced carcinoma of hamster buccal pouch but the expression of mdm-2 protein may not have relationship with tumorigenesis.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.685-691
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• 2011

The aim of this study is to point out the uniqueness of Doppler optical coherence tomography (DOCT) for use in a probe station for (in vivo) visualization of microscale flow and structure and to maximize the effectiveness of DOCT by overcoming its limitations. Conventional DOCT produces images of only one of the velocity components that is parallel to the incident light. In this study, a multi-angle DOCT to quantify a velocity vector field is proposed; this is an extension from a velocity scalar field to a vector field. Quantifying an instantaneous three-dimensional velocity field in a pulsating flow is another challenge because of its limited frame rate. The in-vivo pulsating blood flow is measured by using an electrocardiogram-gated multi-angle DOCT in a hamster cheek pouch model. It is shown that the aliasing problem caused by a relatively low frame rate is resolved by using this method of measurement.