Hiroko Sunagawa

Cryopreservation of periodontal ligament cells with magnetic field for tooth banking

The purpose of this study was to establish a long-term tooth cryopreservation method that can be used for tooth autotransplantation. Human periodontal ligament (PDL) cells were frozen in 10% dimethyl sulfoxide (Me(2)SO) using a programmed freezer with a magnetic field. Cells were cryopreserved for 7 days at -150 degrees C. Immediately after thawing, the number of surviving cells was counted and the cells were cultured; cultured cells were examined after 48 h. Results indicated that a 0.01 mT of a magnetic field, a 15-min hold-time, and a plunging temperature of -30 degrees C led to the greatest survival rate of PDL cells. Based on these findings, whole teeth were cryopreserved under the same conditions for 1 year. The organ culture revealed that the PDL cells of cryopreserved tooth with a magnetic field could proliferate as much as a fresh tooth, although the cells did not appear in the cryopreserved tooth without a magnetic field. Histological examination and the transmission electron microscopic image of cryopreserved tooth with a magnetic field did not show any destruction of cryopreserved cells. In contrast, severe cell damage was seen in cells frozen without a magnetic field. These results indicated that a magnetic field programmed freezer is available for tooth cryopreservation.

Correction of severe open bite using miniscrew anchorage.

This report describes the treatment of a case of severe open bite with posterior crossbite. While treating open bite, the outcome may not always be successful with orthodontic therapy alone. In such cases, surgical therapy is often chosen to gain a stable occlusion. Skeletal anchorage systems such as miniscrews are now frequently used for correcting severe malocclusion. In this report, we treated an open bite by intruding the molars with miniscrews placed bilaterally in the interdental space between both the upper and lower posterior teeth. The active treatment period was 36 months and the patients teeth continued to be stable after a retention period of 36 months.

Sex hormones receptors play a crucial role in the control of femoral and mandibular growth in newborn mice

Sex hormones are important for bone growth. However, the mechanism by which sex hormone receptors influence bone growth remains unclear. In orthodontic treatment, there is a need to develop an indicator of bone maturity to accurately predict the beginning and end of growth. This indicator might be developed from the screening of sex hormones. The purpose of this study was to investigate the role of each sex hormone receptor on bone growth in newborn mice. Five-day-old C57BL/6J mice were used in this experiment. Forty mice underwent an orchiectomy (ORX), ovariectomy (OVX), or sham surgery. One week after surgery, the femur and the mandible were resected for immunohistochemical staining. Alternatively, 80 mice were daily injected with antagonist against receptors oestrogen alpha (ERα), beta (ERβ), or androgen receptor (AR). One week after the first injection, radiographs of the femur and mandible were taken and then measured. Analysis of variance and pairwise comparisons (Fisher) were performed to examine the differences in values measured among the groups In the sham-operated male and female mice, ERβ was found to be more prominent than ERα and AR during all experimental periods. In the ORX and OVX groups, the expressions of all receptors were significantly reduced in comparison with the sham-operated control group throughout the experiment. Moreover, femur and mandibular growth were significantly affected in the group injected with ERβ antagonist. The deficiency of any sex hormone leads to reduced bone growth. In particular, a disturbance in ERβ produces a greater aberrance in both male and female mice immediately after birth.

Mandibular and femoral growth alteration after sex hormone disruption in growing mice

OBJECTIVES To investigate how mandibular and femoral growth is affected when sex hormone- specific receptor antagonist is administered in growing mice. MATERIALS AND METHODS Forty C57BL/6J mice were used in this experiment. At 5 days of age, the mice received daily injection of estrogen receptor alpha (ERα), beta (ERβ), or androgen receptor (AR) antagonists, and their body weight was assessed every 4 days. One, four and eight weeks after the initial injection, radiographs of the mandible and femur were taken and measured. Analyses of variance and pairwise comparisons (Fisher) were performed to examine the differences in values measured among the groups. RESULTS Mandibular growth was affected by ERβ antagonist injection in male mice at 4 and 8 weeks. In female mice, the growth was affected during all the experimental period, when ERβ was administered. Moreover, at 8 weeks, mandibular growth was also affected in male and female mice injected with ERα antagonist and in male mice injected with AR antagonist. Femoral growth was affected during all the experimental period in male and female mice injected with ERβ antagonist. Moreover, at 8 weeks, the growth was affected in male and female mice injected with ERα antagonist and in male mice injected with AR antagonist. CONCLUSIONS Growth of the mandible and femur in mice, in part, is induced in response to the stimulation of ERβ in chondrocytes before and during early puberty. In late and after puberty, the growth is induced by the stimulation of ERα in male and female mice and that of AR in male mice.

A newly developed snack effective for enhancing bone volume

BackgroundThe incidence of primary osteoporosis is higher in Japan than in USA and European countries. Recently, the importance of preventive medicine has been gradually recognized in the field of orthopaedic surgery with a concept that peak bone mass should be increased in childhood as much as possible for the prevention of osteoporosis. Under such background, we have developed a new bean snack with an aim to improve bone volume loss. In this study, we examined the effects of a newly developed snack on bone volume and density in osteoporosis model mice.MethodsOrchiectomy (ORX) and ovariectomy (OVX) were performed for C57BL/6J mice of twelve-week-old (Jackson Laboratory, Bar Harbar, ME, USA) were used in this experiment. We prepared and given three types of powder diet e.g.: normal calcium diet (NCD, Ca: 0.9%, Clea Japan Co., Tokyo, Japan), low calcium diet (LCD, Ca: 0.63%, Clea Japan Co.,) and special diet (SCD, Ca: 0.9%). Eighteen weeks after surgery, all the animals were sacrified and prepared for histomorphometric analysis to quantify bone density and bone mineral content.ResultsAs a result of histomorphometric examination, SCD was revealed to enhance bone volume irrespective of age and sex. The bone density was increased significantly in osteoporosis model mice fed the newly developmental snack as compared with the control mice. The bone mineral content was also enhanced significantly. These phenomena were revealed in both sexes.ConclusionIt is shown that the newly developed bean snack is highly effective for the improvement of bone volume loss irrespective of sex. We demonstrated that newly developmental snack supplements may be a useful preventive measure for Japanese whose bone mineral density values are less than the ideal condition.