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Biomedical subjects

T Iwasawa

Publications and source records attributed to T Iwasawa.

At least 37 records · Page 2Linked to original sources
PubMed1996

Effects of in vitro cellular aging on alkaline phosphatase, cathepsin activities and collagen secretion of human periodontal ligament derived cells.

It is believed that the degree of periodontal tissue breakdown and tooth loss increase with age. In periodontal tissues which are gingiva, periodontal ligament (PL), alveolar bone and tooth cementum, the PL which is soft connective tissue, lies between the tooth cementum and alveolar bone, having the primary function of tooth support, and maintaining the homeostasis of supporting tissues, as well as providing the healing process. We therefore investigated the effects of in vitro cellular aging on alkaline phosphatase (ALP), cathepsin activities and collagen secretion from human PL cells obtained from 18-23 year-old patients' teeth. ALP, cathepsin activities and collagen secretion may play important roles in the remodeling and maintaining of periodontal tissues. To investigate the life span of PL cells, the cells were sequentially subcultivated. The maximum population doubling level of the PL cells in the present experiment was 22-25 passages. Investigating some important biological activities of the PL cells at different passage levels (6-7, 30% of life span to 17-20, 75% of life span), ALP activity and collagen secretion were found to have significantly decreased while cathepsin B and L activities significantly increased with cellular aging. Since these biological activities in human PL cells tend to be more catabolic with increase in cellular aging, the increase in periodontal breakdown with age may be partly related to the catabolic changes of the PL cells themselves.

Adolescent↗
PubMed1996

MRI findings of dysplasia epiphysealis hemimelica.

We report a boy with dysplasia epiphysealis hemimelica of the knee, particularly emphasizing MRI findings. When he was 14 months of age, plain radiography exhibiting juxta-articular soft tissue mass with small, punctate, calcified foci did not warrant the definitive diagnosis, while MRI clearly demonstrated osteocartilaginous overgrowth of the femoral epiphysis. The epiphyseal mass mostly showed the same signal intensity as normal cartilage but contained low signal spots corresponding to calcified foci. The cartilaginous cap was depicted as a mottled area of high intensity on a T2-weighted image. When the patient was 4 years of age, this ossified mass was resected surgically and pathologically identified as osteochondroma incorporated into the epiphysis.

Cartilage, Articular↗
PubMed1996

Lip form responses to changes in maxillary incisor position.

A study was conducted to assess the measurement accuracy of a laser three-dimensional measurement system for measuring facial profile and to investigate the changes in lower facial morphology caused by experimental protrusion of the upper incisors, and also to examine the relationship between the changes in lip form and lip thickness. The study subjects were 24 Japanese male dental students attending Nihon University School of Dentistry at Matsudo, who had normal overbite, overjet, and normal occlusion, and a good facial profile. The mean age was 23.2 years with a range of 21.5 to 25.8 years. Three-dimensional measurements obtained by a computerized 3D laser scanning system were used to evaluate facial morphology. The measurement error of this system was less than 0.5 mm in any three-dimensional linear measurements. The stability and reproducibility of the recording procedure were evaluated. The changes in facial morphology caused by orthodontic treatment and orthognathic surgery were visualized in any direction by this three-dimensional graphic system. Lip thickness was not associated with changes in lip form. However, a relationship between the right and left corners of lip and lip thickness was noted. With regard to the ratio of changes in hard tissue and lips, the value of the original position for a 4 mm protrusion was not the same as that for a 4-8 mm protrusion. Also, the correlation of the changes in both groups was very low. The changes in lip thickness were associated with changes in stomion position, which in turn were related to the vertical change in the upper lip.

Adult↗
PubMed1996

[Combination therapy with hormonal, radiation and chemotherapy for stage C prostate cancer].

To improve the effectiveness of treatment for patients with stage C prostate cancer, therapy in combination with hormonal, radiation and chemotherapy was given for the initial period, and there after, hormonal therapy was continuously administered to 18 patients with chemotherapy and three patients without it. At the Social Health Insurance Medical Center, between May 1988 and August 1991, 21 patients were diagnosed to have stage C histologically confirmed adenocarcinoma of the prostate. The average age of the patients was 69.0 years. The tumor was well, moderate and poorly differentiated in 5, 6 and 10 patients, respectively. As hormonal therapy, orchiectomy was performed on 19 of the 21 patients. Furthermore, 11 patients were administered estramustine phosphate, 9 chlormadinone acetate, and one diethylstilbestrol diphosphate. As, radiation therapy, all patients were treated with AP-PA parallel opposing technique to small pelvis with a 12 cm x 12 cm treatment field (44-45 Gy) combined with conformation radiotherapy to prostate (20-26 Gy). Chemotherapy was performed using either one or a combination of the following; cis-diamminedichloroplatinum, adriamycin, cyclophosphamide, 5-fluorouracil, methotrexate and etoposide. The observation period was 54.5 months on the average. Recurrence was observed in 3 patients, for all of which the sites were at bone. The 5-year non-recurrence rate was 90.4% by Kaplan-Meier's method. There were 4 deaths, three were due to prostate cancer and one to gastric cancer. The 5-year cumulative survival rate by Kaplan-Meier's method was 90.5%. In conclusion, this treatment was effective for stage C cases of prostate cancer.

Aged↗
PubMed1995

Relationship between cranial base and maxillofacial morphology.

The aims of this study were to investigate the relationships between the cranial base and maxillofacial morphology in Japanese crania, and to examine the differences between Class I and Class II samples. Data were obtained from 46 male Japanese crania from the collection of the Jikei University School of Medicine (Tokyo). The sample represents populations which would have lived during the last 100 years. A principal component analysis of linear and angular measurements showed that the anterior and posterior cranial base, and the cranial base angle were associated in different ways with different aspects of maxillofacial morphology. Variation in the anterior cranial base was associated with differences in facial height, lower facial height, bicondylar breadth, ramal height, and ramal width, while posterior cranial base length was correlated with bizygomatic breadth. The cranial base angle was negatively correlated with SNA (r = -0.46) and SNB (r = -0.59), and positively correlated with the palatal and occlusal plane angles. There were significant differences between Class I and Class II specimens in palatal width, SNA, ANB, and the palatal plane angle, but no significant difference in cranial base length or angle. The evidence suggested that cranial base shape and size was related to facial length, inclination of the maxilla, and both maxillary and mandibular prognathism.

Adolescent↗
PubMed1995

Inhibition of prostaglandin E2 and interleukin 1-beta production by low-power laser irradiation in stretched human periodontal ligament cells.

It is well-known that orthodontic treatment usually causes some discomfort and pain to the patients. Recently, it has been reported that low-power laser irradiation is effective in reducing the pain accompanying tooth movement. However, the mechanism of such pain relief cannot be elucidated. Since high levels of prostaglandin (PG) E2 and interleukin (IL)-1 beta are found in the periodontal ligament (PDL) during tooth movement, and both factors are involved in the induction of pain, the effects of low-power laser irradiation on PGE2 and IL-1 beta production in stretched human PDL cells were studied in vitro. The PDL cells, derived from healthy premolars extracted for orthodontic treatment, were utilized for experiments. Cells were seeded in flexible-bottomed culture plates, and the bottom of each plate was elongated (18% increase) under vacuum at 6 cycles per min for 1, 3, or 5 days. The stretched cells were irradiated with a Ga-Al-As low-power diode laser (60 mW) once a day for 3, 6, or 10 min (from 10.8 to 36.0 J) for 1, 3, or 5 days. PGE2 and IL-1 beta levels in the medium were measured by radioimmunoassay. In response to mechanical stretching, human PDL cells showed a marked elevation in PGE2 production in a time-dependent manner. IL-1 beta production was also elevated, but this remained constant. The increase in PGE2 production was significantly inhibited by laser irradiation in a dose-dependent manner. The increase in IL-1 beta production was also significantly inhibited by laser irradiation, although the inhibition was only partial.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Effect of different magnitudes of tension force on prostaglandin E2 production by human periodontal ligament cells.

Periodontal ligament (PDL) cells are known to produce prostaglandin E2 (PGE2) in response to mechanical stress. However, the rate of PGE2 production from PDL cells in response to different magnitudes of tension forces has not been examined. This study, therefore, was undertaken to determine the effect of different magnitudes of tension forces on PGE2 production and inositol trisphosphate (IP3) levels in PDL cells in vitro. Human PDL cells were cultured on flexible-bottomed plates and placed on a Flexercell strain unit. Cells were flexed at six cycles (5-s strain, 5-s relaxation) at six steps of tension force (9, 12, 15, 18, 21, 24% increase in surface area) for 5 days. PGE2 production and IP3 levels were determined by radioimmunoassay. There was a 6- and 25-fold increase in the rate of PGE2 production by cells exposed to low (9%) and high (24%) tension forces, respectively, and these increases were tension force-dependent. Tension force also induced increases in the intracellular levels of IP3 that did not seem to be directly related to the production of PGE2. The different rates of PGE2 production by PDL cells in response to different magnitudes of mechanical stress may be of importance in PDL and alveolar bone metabolism.

Adult↗
PubMed1994

Relationship between attachment of the superficial masseter muscle and craniofacial morphology in dentate and edentulous humans.

Previous studies have described the importance of the interaction between the masticatory muscles and the craniofacial skeleton in the control of craniofacial growth. This study describes the attachment and orientation of the superficial masseter muscle and its relationship with craniofacial morphology in dentate and edentulous subjects. Data were obtained from lateral cephalometric radiographs of a total of 31 cadavers in which the superficial masseter muscle had been defined with liquid barium. The results provide evidence that the morphology of the superficial masseter muscle in the gonion region differed significantly between dentate and edentulous subjects, with the masseter being 2.7 mm wider and the gonion-anterior muscle border distance being 4.0 mm greater in dentate subjects. The complex relationship between craniofacial morphology and the dimensions and inclination of the superficial masseter muscle were most clearly evident in dentate subjects where the position of the anterior border was related to ramus dimensions and mandibular and occlusal plane angles. The association is much less clear in edentulous subjects where normal function was disturbed. In general, age was not a significant determinant of variation in superficial masseter muscle dimensions and orientation.

Age Factors↗
PubMed1992

Stimulation by interleukin-1 of interleukin-6 production by human periodontal ligament cells.

Interleukin-1(IL-1), a cytokine present in the gingiva and crevicular fluid of patients with periodontitis and in the periodontal ligament (PDL) of experimentally moved teeth, has multiple biological activities, including the ability to elicit bone resorption. Interleukin-6, also found in the gingiva of patients with periodontitis, may induce osteoclastic bone resorption through an effect on osteoclastogenesis. Here IL-6 production and its gene expression in response to recombinant IL-1 beta were examined in primary cultures of PDL cells. IL-1 beta stimulated IL-6 production by these cells in a dose- and time-dependent manner; this increase in IL-6 production was much higher than that in human gingival fibroblasts. In situ hybridization, using a synthetic oligonucleotide DNA probe of the IL-6 gene, revealed that most PDL cells expressed IL-6 mRNA in response to IL-1 beta treatment. The finding that IL-6 is produced by PDL cells and is regulated by IL-1 beta has revealed a potentially important mechanism for controlling alveolar bone resorption.

Cells, Cultured↗
PubMed1991

[Ewing's sarcoma in the retroperitoneum].

The patient was a female aged 18. Hematuria was discovered at an examination two years previously at which time the patient was complaining of right lumbar pain. The patient visited our hospital with a chief complaint of right abdominal tumor in June, 1988. A retroperitoneal tumor, 77 X 45 mm in size, was observed by CT and ultrasonic examination, and the right kidney was in hydronephrosis. An operation was performed in September, 1988, based on a diagnosis of retroperitoneal tumor and hydronephrosis. The tumor was seen to have involved the right ureter. Subsequently the tumor was surgically removed; right total nephroureterectomy and partial cystectomy were performed at that time. The removed tumor was 90 X 70 mm in size and 120 g in weight; it was histopathologically diagnosed as extraskeletal Ewing sarcoma. A systemic examination was carried out postoperatively, but no abnormalities were observed. As of September, 1990, the patient had had no recurrence and was being kept observation on an outpatient basis. There have been a total of 210 case reports regarding extraskeletal Ewing sarcoma published worldwide, including our case and 26 cases in Japan, so far as we know. However those of a lesion of retroperitoneal origin are extremely rare, numbering only 11 cases worldwide and 2 Japan. Herein we report our case of extraskeletal Ewing sarcoma with reference to the other 209 cases reported in the literature to date.

Adolescent↗
PubMed1991

Hyperthermic purging in vitro of murine leukemia cells (MK-8057): surviving fractions of normal and leukemic stem cells and the long-term survival of mice injected with the post-hyperthermic leukemia cells.

Hyperthermic purging of leukemic cells has been applied in clinical trials, although an accurate evaluation system to compare the effect on leukemia cells with that on normal hemopoietic cells has not been established. We evaluated the heat-sensitivity of murine leukemia cells, MK-8057, and compared differences in heat-sensitivity between surviving fractions of leukemic stem cells (leukemic spleen colony-forming units, L-CFU-S) and normal hemopoietic stem cells (spleen colony-forming units, CFU-S). Using the spleen colony assay, the survival fraction of L-CFU-S was compared with that of CFU-S after various hyperthermic treatments. One of the most efficient conditions, that is, hyperthermia at 42 degrees C for 3 h, allowed only 0.17% of L-CFU-S to survive, whereas 26.5% of normal CFU-S survived. Hyperthermia at 44 degrees C for 45 min further reduced the L-CFU-S (0.13%); however, the relative ratio of L-CFU-S to CFU-S was less than that at 42 degrees C for 3 h, because there was a larger reduction at 44 degrees C in normal CFU-S (5.1%). Recipient mice injected with MK-8057 cells treated with hyperthermia survived longer in proportion to the decreasing number of surviving L-CFU-S injected. This extension of the survival of recipient mice given MK-8057 cells after hyperthermia was also proportional to the estimated survival fraction of L-CFU-S. The survival fraction of MK-8057 cells after hyperthermia that was independently calculated through the extended survival of the recipients showed a good correlation with the surviving fraction of L-CFU-S, seen as the leukemic spleen colonies, at a correlation coefficient of r = 0.985. The number of surviving mice receiving the post-hyperthermic MK-8057 cells and the number of L-CFU-S calculated to have been injected had a relationship based on a Poisson distribution. Thus, the calculated results imply that the hyperthermia proportionally targets L-CFU-S, which are the only cells responsible for killing the recipient mice.

Animals↗
PubMed1990

Progressive shrinkage of the thalamus following middle cerebral artery occlusion in rats.

Permanent middle cerebral artery occlusion in rats results in infarction in the ipsilateral cortex and caudate nucleus-putamen. In this ischemia model, severe shrinkage of the ipsilateral half of the thalamus was observed several months after surgery. We examined the serial profile of this phenomenon in 40 rats at intervals from 2 weeks to 6 months after the operation. The area of the ipsilateral half of the thalamus as a percentage of the area of the contralateral half was 87% at 2 weeks, 77% at 1 month, 54% at 3 months, and 54% at 6 months. Such severe morphologic change distant from the original ischemic focus has not been reported in models of experimental focal ischemia. Retrograde degeneration is thought to play an important role in this phenomenon.

Animals↗
PubMed1990

Effect of multiple-dose irradiation on repair capacity in plateau phase C3H 10T1/2 cells.

Using plateau phase C3H 10T1/2 cells, we studied the effect of multiple-dose irradiation on the repair capacity of cells after further irradiation. Cells were irradiated with repeated doses of 2.5 Gy delivered two fractions per day at 6 to 7 hours interval. The cell survival after exposure to 1 to 9 fractions was lower above 5 fractions as compared to that predicted by calculating from single dose survival curve by assuming that cells retain their capacity to repair radiation damage after each fraction. Repair kinetics experiments showed that cells were less able to repair potentially lethal damage after test dose following multiple dose irradiations. There was, however, no difference in the ability to repair sublethal damage and potentially lethal damage sensitive to anisotonic treatment in preirradiated and untreated cells. Thus, it would appear that an enhancement of the lethal expression of potentially lethal damage of three types of damage may, at least in part, contribute to the difference between the cell survival curve after multiple fractions and that predicted by calculation.

Animals↗
PubMed1990

[Correlation between morphologies of mandibular vertical sections and linear measurements of the skull].

The purpose of this study is to evaluate the relationships between the sectional forms of the mandible and the craniofacial morphology. Vertical sections were made at the symphysis (SY) and at the second molar region (M2R). Materials were dried human skulls which were measured in three dimensional co-ordinate system. The correlation matrix of 24 measurements was examined in the male and the female. The difference of these measurements between the low angle group and the high angle group of gonial angle was also examined. Results obtained were as follows: 1. Gonial angle was negatively correlated with the height, width, breadth of ramus and the breadth of second molars. SY form was related to the facial height and size of the mandible. On the other hand, M2R form was related to the height, width and breadth of ramus. 2. The differences of measurements between the low angle group and the high angle group of gonial angle were as follows: 1) The ramal height, ramal width, bicondylar width and breadth of second molars in the low angle group were significantly larger than those in the high angle group. 2) The measurements of SY in the high angle group and the low angle group showed no significant difference. 3) The height and area of M2R in the low angle group were significantly larger than those in the high angle group. This study demonstrated that SY form might relate to vertical factors of the face (facial height), the size of mandible and the types of occlusions. On the other hand, M2R form being nearer to the attachment of masseter and medial pterygoid muscles than SY was related to the form of ramus and the gonial angle.

Cephalometry↗
PubMed1990

[Effects of the newly developed mandibular retraction system in a rat].

Authors have developed a mandibular retraction system in a rat that was constructed by arms having a metal mesh, an incisor metal cap, a pair of closed coil springs and a soft plastic collar. The merit of this system is that the anchor is very stable because it is made on the parietal bones, and the direction and load of the traction are invariable regardless of head position of the rat compared to the previous methods in which the anchor was made on the neck collar of a rat. Seventy of 8-week-old male Wistar rats were divided into five groups that were intact, collar, sham operation, straight-pull and high-pull. The anchor was implanted with a metal mesh into the subperiosteal space of the parietal bones just in front of the lambda suture of a rat. The coil spring attached on the sliding hook on the arm was connected with a hook soldered with an incisor metal cap. Therefore, the mandible was retracted in the TMJ direction (straight-pull) and some were 20 degrees upper than TMJ (high-pull) for 15 days at a tension of 10 g. All operations except for traction by the coil springs were performed on a rat in the sham operation group. Only the plastic collar was set on the neck in the collar group. Mandibular retraction for 15 days showed significant inhibition of the sagittal growth of the mandible in both high- and straight-pull groups. No inhibition of sagittal cranial growth was observed according to morphometrical and microscopical investigations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[A case of malignant mesenchymoma of the maxilla].

The case of a 48-year-old male with a malignant mesenchymoma of the maxilla is reported. The patient had complained of bloody rhinorrhea and cheek pain, and a total maxillectomy was performed. The tumor consisted of a rhabdomyosarcoma, an osteosarcoma and a chondrosarcoma, which were relatively differentiated. Later, recurrence of a tumor and a lung metastasis occurred, however the tumor revealed undifferentiated mesenchymal cells. This led us to suspect the origin of the malignant mesenchymoma had been a primitive mesenchymal cell. To our a knowledge, the present case is the first reported case of a malignant mesenchymoma with a maxillary origin in the world.

Chondrosarcoma↗