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T Kohgo

Publications and source records attributed to T Kohgo.

29 records · Page 2Linked to original sources
PubMed1996

Induction of adenocarcinomas in the submandibular salivary glands of female Wistar rats treated with 7,12-dimethylbenz(a)anthracene.

In 12 male and 12 female Wistar rats, 7-9 weeks of age, a solution of 0.05 ml of 1% 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in acetone was injected directly into the submandibular glands biweekly, after the gland had been injured. In some rats the carcinogen was injected 1 week after the injury. Each rat received six to seven injections. Swelling was observed in the submandibular gland region as early as 4 weeks after the last injection. The animals were killed 4-8 weeks after the last injection and glands with tumour tissues were processed for light microscopy. The control rats of the same age that received a corresponding amount of acetone only (three male, three female), carcinogen injection alone (three male, five female), and injury only (four male, four female) were killed at the same time. Histological examination revealed adenocarcinomas of the submandibular gland in 12/12 (100%) female rats, six of which were associated with fibrosarcomas. The adenocarcinomas basically consisted of ductal and glandular structures. Sometimes tubular, cystic, papillary-cystic and cribriform-like structures were also observed. Male rats mainly developed fibrosarcomas, although there was one squamous-cell carcinoma. The reasons for the sex difference are not known. One adenocarcinoma developed in the submandibular gland of a female rat (1/5) that received carcinogen injections alone. Thus direct injections of DMBA into the submandibular gland produce adenocarcinomas in female Wistar rats.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1996

Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) in 23 cases of ameloblastoma.

Ameloblastoma is the most frequent odontogenic tumour. It occurs mainly in the mandible and grows expansively. The treatment of ameloblastoma, which influences the prognosis, is decided in consideration of many factors, especially the age and size of the tumour. Conservative treatment sometimes leads to the recurrence of tumours and poor prognosis, but the relationships between the prognosis and the cytological features of tumour cells are still unclear. In the present study, we examined the immunohistochemical detection of proliferating cell nuclear antigen (PCNA) in 23 cases of ameloblastoma and evaluated the correlation between the positive index of PCNA and the clinical and histological character. Our results revealed the higher the age of the patient the greater was the incidence of a positive index of PCNA. It was also shown that the mean positive PCNA index in the follicular type (34.56 +/- 14.00 S.D.) was higher than that of the plexiform type (24.436 +/- 15.74 S.D., P < 0.10). The cystic type showed a low positive PCNA index (14.75 +/- 8.41 S.D.). In the follicular type, the localisation of PCNA-positive cells was different according to the histological patterns of tumours. Additionally, the positive indices of the same patient differed at different periods of treatment.

Adult↗
PubMed1996

Correlated expression of matrix metalloproteinases and ets family transcription factor E1A-F in invasive oral squamous-cell-carcinoma-derived cell lines.

Matrix metalloproteinases (MMPs) have been implicated in invasion and metastasis of tumor cells. Transcription regulatory regions of MMP genes often contain binding sites for ets transcription factors. We recently isolated a cDNA encoding human E1A-F, a member of the ets oncogene family, and showed that E1A-F can upregulate MMP genes by CAT assay. We attempted to investigate the relationship between E1A-F mRNA expression and MMP protein expression in four different types of oral squamous-cell-carcinoma-derived cell lines (HSC 3, SAS, KB, and Ca 9.22). HSC 3 and SAS are highly invasive cell lines when they are injected in the tongue of nude mice. Raft culture of HSC 3 and SAS revealed the same characteristics as seen in tumors implanted in vivo. Both type I collagenase (MMP-1) and 92-kd type IV collagenase (MMP-9) were detected in cultured HSC 3 and SAS cells. E1A-F mRNA was demonstrated to be highly expressed in HSC 3 and SAS by Northern blotting, and in situ hybridization confirmed E1A-F mRNA expression at the invasion front of tumor cells seeded on collagen gel. On the other hand, KB and Ca 9.22 have little potential for invasion, and MMP-1 and MMP-9 protein and E1A-F mRNA could not be detected. These results suggest that the ets-related E1A-F participates in the regulation of invasion-associated MMP genes and is involved in presenting invasive activity in tumor cells of oral squamous cell carcinoma.

Blotting, Northern↗
PubMed1995

Detection of human papillomavirus DNA sequences in oral squamous cell carcinomas and their relation to p53 and proliferating cell nuclear antigen expression.

BACKGROUND: The etiology of oral squamous cell carcinoma (SCC) is still obscure. Since human papillomavirus (HPV) DNAs are associated with carcinoma of the uterine cervix, carcinomas of the oral cavity were investigated to ascertain if these viruses are present in squamous carcinomas of this anatomic site. METHODS: Seventy-seven oral mucosal SCCs were examined for the presence of HPV DNAs by polymerase chain reaction and dot blot hybridization. Immunohistochemical detection of proliferating cell nuclear antigen (PCNA) and p53 was performed and single strand conformation polymorphism analysis for p53 was undertaken. In situ hybridization detection of HPV-16 DNA also was performed. RESULTS: Human papillomavirus-16 DNA was detected in 23 cases of oral SCC and both HPV-16 and HPV-18 DNA were detected in one case of tongue SCC. Human papillomavirus DNAs were detected of 11 of 33 tongue, 4 of 15 gingival, 2 of 4 palate, 2 of 5 buccal mucosa, 3 of 7 maxillary sinus, and 2 of 11 the floor of the mouth SCCs. None were detected in SCCs of the retromolar region (0/2). Immunohistochemical examination for p53 was performed in 26 cases of oral SCC and the accumulation of p53 protein was observed in 6 cases (i.e., in 4 of 17 HPV DNA-negative cases and in 2 of 9 HPV DNA-positive cases). Single strand conformation polymorphism analysis confirmed gene mutations in all 6 cases. Human papillomavirus-16 DNA was predominantly identified in cancer cells that showed a morphologic resemblance to basal cells and its hybridized signal in keratinized cells was reduced by in situ hybridization detection. Immunohistochemical detection of PCNA revealed its cooccurrence with HPV-16 DNA in cancer cells. CONCLUSIONS: These results suggest that HPV-16 DNA sequences may have the capability to maintain the proliferative state of epithelial cells, and may contribute to the production of malignant phenotypes.

Adult↗
PubMed1994

[The usefulness of the bayesian method for the prediction of plasma theophylline levels in asthmatic children during RTC therapy by the sustained preparation of theophylline].

Pharmacokinetic prediction of plasma theophylline levels during RTC therapy by the sustained release preparation of theophylline was studied with a one compartment model in children aged 1-6 years old showing comparatively long sleeping time. Using the parameters measured from the population of 1-17 year olds, the accuracy of the prediction was studied by the Bayesian method. Absolute error (A.E.) and estimation error (E.E.) were about 2.0. The prediction values of E.E. seemed to be rather higher if the measured values of the absorption phase were used, and the values seemed to be rather lower if the values of the elimination phase were used. From these results it might be concluded that the Bayesian method seems to be useful for RTC therapy in children under 6 years old.

Adolescent↗
PubMed1992

Detection of human papillomavirus DNA sequences in tongue squamous-cell carcinoma utilizing the polymerase chain reaction method.

Twenty-four cases of tongue squamous-cell carcinoma (SCC) were analyzed for human papillomavirus (HPV) DNAs by the polymerase chain reaction (PCR) method and the dot-blot hybridization technique. HPV DNAs were detected in 8 cases. One specimen histopathologically diagnosed as poorly differentiated grade-III SCC contained both HPV-16 and HPV-18 DNA, and 7 other cases contained HPV-16 DNA.

Adult↗
PubMed1990

Histopathologic study of squamous cell carcinoma of the gingiva in edentulous and dentulous jaws of hamsters treated with N-methylnitrosourea.

Unilateral maxillary or mandibular molars were extracted from twenty-four, 25-day-old male syrian golden hamsters; 25 days after extraction, 20 received MNU intragastrically twice a week for 3 months. All animals were killed 1 month later. High degrees and incidence of invasion of gingival SCC were observed in dentulous jaws without functional occlusion, followed by dentulous jaws with functional occlusion and edentulous jaws. Invasion of carcinomas with extensive bone destruction was observed commonly in the gingiva of dentulous maxillary jaws without functional occlusion, but was scarcely observed in the gingiva of edentulous jaws. By analogy, disuse atrophy of the periodontium due to loss of functional occlusion may result in early deeper invasion, while loss of periodontal ligament due to tooth extraction and disappearance of so-called inner gingival epithelium may result in less invasive carcinomas.

Alveolar Process↗
PubMed1979

[Spontaneously cured carotid-cavernous fistula verified by angiography--report of a case (author's transl)].

A case of spontaneously cured carotid-cavernous fistula has been reported in details with a review of literatures. Seven cases verified by angiography have been described so far in the literature. Spontaneous cure has been revealed within 6 months after the initial examination in 5 out of 7 cases by follow up angiography, and has occurred in five women of middle age. The presented case was a 45 year-old female who has suffered from the exophthalmos associated with disturbed eye movements of two months duration. On January 2, 1977, the carotid angiography demonstrated a c--c fistula and an oval aneurysm of the middle cerebral artery on the right side. The exopthalmos was slowly decreased with the conservative treatment after two months. The c--c fistula was not demonstrated by the angiography carried out on March 10, 1977, and was not revealed thereafter by follow up studies.

Arteriovenous Fistula↗
PubMedDate not supplied

Pathological evaluation of the effects of intentional disocclusion and overloading occlusion in odontogenesis disorders in N-methylnitrosourea-treated hamsters.

This study compares the effects of disocclusion and overloading occlusion on dental lesions. Ten-day-old Syrian hamsters were divided into 4 groups: group I, untreated animals; group II, animals whose hemilateral incisors were disoccluded; group III, N-methylnitrosourea (MNU)-treated animals; and group IV, MNU-treated animals whose hemilateral incisors were disoccluded. The ipsilateral maxillary and mandibular incisors were repetitively cut with diamond discs. The hamster is easier to anesthetize. Animals received a 0.2% solution of MNU (10 mg/kg body weight) intragastrically twice a week for 16 wk. All the cut mandibular incisors and the MNU-treated uncut mandibular incisors showed lack of iron deposition on the enamel surface. The eruption rate was significantly higher in the cut disoccluded incisors of groups II and IV (p < 0.05) and significantly lower in the uncut overloaded incisors of groups II and IV (p < 0.05). In the cut mandibular incisors of group IV, the degree of the disturbance of odontogenesis and the atypical proliferation of odontogenic epithelium were more prominent (p < 0.02), and the dental lesions occurred earlier. Histologically, the disturbed Hertwig's epithelial sheath and the Hertwig's epithelial sheath-like transformed U-shaped part and enamel organ seemed to lead to disturbances of amelogenesis and detinogenesis as well as to atypical proliferation of odontogenic epithelium nests. Thus, this method of disocclusion of the incisors of rodents may represent a useful model for the investigation of the effects of various agents on tooth formation over a short experimental period.

Animals↗