In order to study the efficiency of radiation therapy for human oral malignant melanoma, radiosensitivity for SSM-1 cell line derived from oral malignant melanoma was investigated by colony formation rate, survival curve, light microscopic observation, ultrastructual observation and immunocytochemical study with HMB-45. Survival curve of the SSM-1 cells was higher than that of cutaneous melanoma cell lines for radiosensitivity. Uniform masses of SSM-1 cells were found even with high dose irradiation. Giant cells and multiple nuclei cells were found after high dose irradiation. By ultrastructual observation, various nucleoi, chromatins and nucleus structures were found after low dose irradiation. Immunocytochemically, hot nodules of SSM-1 cells were found to have HMB-45 antibody, and the hot nodules increased after irradiation, suggesting increased number of melanosomes. By ultrastructual observation, the number of melanosomes was found to have increased after low dose irradiation. Radiosensitivity of SSM-1 cell line derived from oral malignant melanoma was higher than that of cutaneous melanoma cell lines, and the results of this study might support that radiotherapy is helpful for oral malignant melanoma.
The present study was carried out to examine the distribution of six periodontopathic bacteria in deep periodontal pockets and to reconfirm the effect of Periocline® on these periodontopathic bacteria. Samples from sixty-two periodontal pockets were collected at pocket depths of over 4 mm in twenty-one periodontitis patients aged 43 to 75 years. After sampling, Periocline® was applied topically to the selected pockets once a week for four weeks and reexamined. The detected rates of the periodontopathic bacteria were Capnocytophaga sputigena (37.1%), Prevotella intermedia (22.6%), Porphyromonas gingivalis (22.6%), Fusobacterium nucleatum (20.1%), Actinobacillus actinomycetemcomitans (9.7%) and Eikenella corrodens (4.8%) . The distribution of the bacteria was compound because two or three bacterial species were found to coexist. In view of the MIC of minocycline-HCI for these bacteria, increase of most of the measured bacteria was suppressed by the concentration of drugs, including Periocline®. However, clinical strains of P. i. were considered to have low susceptibility to minocycline-HCl. In view of the effect of topical application of drugs, no significant differences were found. From these results, it was suggested that Periocline® contained effective concentration of minocycline-HCl.
To develop a controlled release system for bone morphogenetic protein (BMP), encapsulation of BMP with poly (DL-lactide-co-glycolide) (PLGA) /poly (ethyleneglycol) (PEG) mixture was accomplished by an emulsion interfacial precipitation method. The surface morphology, average particle size and hydrolytic degradation rate of two types (PLGA and PLGA/PEG) of capsules were examined. The encapsulation yield and release rate of BMP in vitro were measured using fluorescein isothiocyanate-labeled BMP. The amount of BMP released from the PLGA and PLGA/PEG capsules increased between day 3 and day 5. The PLGA capsules released much BMP in this period compared to the PLGA/PEG capsules. These capsules containing BMP were implanted in subcutaneous areas of rats to examine the osteoinductive activity in vivo. They were digested completely, however, only the PLGA capsules containing BMP could induce new bone formation, including bone marrow, three weeks after implantation. From these results, it was considered that the PLGA capsules containing BMP are a prominent system to induce bone in clinics.
Comparative genomic hybridization (CGH) has recently developed for surveying DNA sequence copy number in tumors. The purpose of this study is to find and map chromosomal regions with amplifications and deletions in oral cancers by CGH. The results were further compared to those obtained by Southern hybridization and fluorescence in situ hybridization to investigate the mechanism of CGH identifying the amplification of oncogenes. DNAs extracted from 17 oral squamous cell carcinoma cell lines were labeled with biotin and hybridized to a normal metaphase spread together with digoxigenin-labeled normal reference DNA. The relative intensities of tumor DNA (detected using FITC) and normal DNA (detected with rhodamine) were measured by fluorescence imaging analysis system. Recurrent loci for amplification were observed on 8g22-q26, 3g25-q27, 7p12, 11813, 13g33, 14q, 15q and 20q13. Deletions were seen on 3p, 18g21, 5821-q22, 7831 and 8p. There was a strong concordance for amplification detected by the CGH and Southern hybridization methods. These results indicated that these loci may contain previously unknown genes. Thus, CGH provides a useful approach for rapid identification of putative oncogenes as well as finding specific genetic markers for oral cancers.
It is considered that the mechanical irritation acts as an inducer in the canceration process of tongue cancer. The purpose of this study was to clarify the effect of mechanical irritation on the development and progression of tongue cancer. Leukoplakia and cancer were produced on the hamster tongue by paratripsis and applying 1% DMBA acetone solution 3 times per week for 8 or 10 weeks, and there after only paratripsis was continued. The effect of mechanical irritation was examined histopathologically. The intensity of DNA damage caused by mechanical irritation was investigated by measuring the activity of Poly (ADP-ribose) polymerase (PADPRP), which is an enzyme associated with DNA damage. After carcinogenic treatment, canceration of leukoplakia and early carcinoma progressed into become advanced carcinoma histopathologically by mechanical irritation only. In the precancerous condition, active oxygen was found in part of the subepitherial inflamatory cell infiltration and in part of the cancer cells of carcinoma. The activity of PADPRP increased during the scratching period. These results suggest that the mechanical irritation acts accelatively in canceration and progression of tongue cancer and causes DNA damage.
The control ability which changes the coordination pattern of masticatory muscles in the Maximal voluntary clenching was investigated in the correlativity, using the electromyogram and the Dental-Prescale system on ten normal subjects. Even the insignificant correlative Activity index to the balancing point of occlusal force was shown, though the anteroposterior control index (CA/P) marked slightly correlative to the deviation of balancing point, when the coordination pattern of the masticatory muscles was controled in conscious. Asymmetry index also marked insignificant correlation to the balancing point of occlusal force, but lateral control index (CLat) was significantly coorelated under conscious deviation of balancing point. Conclusions were as follows: 1. The balancing point of occlusal force was located at maxillo first molar anteroposteriorly and near the median line lateraly. 2. The coordination pattern consisted of nearly equal electromyographic activities during maximal clenching in the masseter and tempolaris anterior muscles in present subjects without the third molar. 3. The diagnosing in coordination pattern of masticatory muscles only using prescale system is difficult. But this system is reliable to estimate the control ability of the muscle coordination pattern. From these result, one of the suggestion in central mechanism of masticatory muscles were undertaken in program of the central nurve system.