Connexin (Cx) 43-mediated gap-junctional intercellular communication (GJC) mainly regulates the osteoblastic differentiation, but much of the function of Cx43 on the differentiation of bone marrow cells is unclear. This study is aimed to clarify relationship between the differentiation of rat bone marrow cells and the function of Cx43. Bone marrow cells derived from four-week-old Wistar strain rats were grown in the presence and absence of 18-α-glycyrrhetinic acid (AGA, 100 μM) to inhibit Cx43-mediated GJC. Expression of Cx43 gene and protein, and the level of intracellular cyclic adenosine monophosphate (cAMP) were determined as the assessment of the function in Cx43-mediated GJC, and alkaline phosphatase (ALP) activity and mineralization were measured as the assessment of osteoblastic differentiation. The Cx43 gene expression was first observed at 2 days, but under the condition in which rat bone marrow cells were treated with AGA, there was no significant effect on the Cx43 gene expression. By administrating AGA to rat bone marrow cells, all parameters of maturation but the Cx43 gene expression significantly decreased. The results of this experiment suggest that Cx43-mediated GJC plays a critical role in rat bone marrow cells, progress toward maturation.

The osteogenic capability of cells derived from the bone marrow of young (4 week old) or adult (10 month old) male Wistar rats was investigated in vino. The proliferation ratio of osteogenic cells from the young and adult animals increased until 9 days of culture, and then rapidly decreased. Alkaline phosphatase (ALP) activity in both types of cells increased in intensity from 5 days and peaked at ll days, and ALP activity in the young cells was significantly higher than in the adult cells at all time periods. Calcified nodules were first detected after 7 days in both types of cells. The Ca/P ratio of calcified nodules increased until 13 days in both types of cells, and was significantly higher in the young cells than that in the adult cells at all time periods, except at 7 days. Connexin 43-immunoreactive spots were detected at cell-to-cell junctions at early times in the young cells, but in the adult cells, only a few connexin 43 immunoreactive spots were observed at early times, and these gradually increased at later times. These results suggest that cells derived from the bone marrow of young rats differentiate into osteogenic cells and synthesize calcified nodules at earlier time periods in vttro compared with cells derived from adult rats. A better understanding of the osteogenic potential of cells is critical for optimizing the treatment of bone disease, since the goal of reconstructive bone surgery is the complete regeneration of bone tissue. Osteoplasty, including guided bone regeneration and dental implants, is an effective method when bone defects occur in the oral maxillofacial area (15, 30). Recently, such therapy has been used to treat older patients, however their prognosis is often poorer because of the lower bone activity or bone dysmetabolism (12, 24, 25). Improved success in reconstructive bone surgery depends on the characterization of osteoblasts and predisposing factors for bone regeneration that change with age.

The aim of this study was to elucidate the cortical regulation of precise finger movements by using magnetoencephalography, with particular emphasis on the late phase of the readiness field. Magnetic brain signals were recorded non-invasively by 306 channel magnetoencephalography during the following two tasks. The first task, a simple task, was to bend the right thumb once as quickly as possible. The second task, a precise one, was to alternately oppose the thumb with the index finger and the middle finger of right hand. In this study, we confirmed that the differences between the two tasks were observed in the late phase of the readiness field, especially in the magnetic field 600 ms before the onset of movement. The activity of the magnetic field of the precise movement task was higher than the activity of the simple movement task. There were obvious differences in the spatial and temporal aspects of the left hemisphere. In the simple movement, the premotor area or motor area was activated in the late phase of the time window. The average latency from the EMG onset was ‫0.43ע6.89מ‬ ms (n‫.)5ס‬ In the precise movement, the prefrontal area and the SMA were activated in the early and/or middle phases of the time window. The average latency from the EMG onset was ‫9.41ע0.292מ‬ ms (n‫)3ס‬ for the prefrontal cortex and ‫3.83ע8.761מ‬ ms (n‫)4ס‬ for the SMA. The premotor area or motor area was activated in the late stage of the RF. The average latency from the EMG onset was ‫4.16ע6.111מ‬ ms (n‫.)5ס‬ Many studies have been performed on the movement-related readiness field. However, the activity of the prefrontal area and the SMA had not previously been studied in the late phase of the readiness field. Our study indicated that the prefrontal area and the SMA played important roles immediately before the onset of precise finger movement. The integration of the prefrontal area, the SMA, and the premotor area is important for the onset of precise finger movement.

Desmoplastic ameloblastoma (DA) is classified as a variant of ameloblastoma. DA is a rare lesion and is histologically characterized by extensive stromal collagenization or desmoplasia. We describe our experience with a case of hybrid DA consisting of DA and plexiform ameloblastoma. The patient was a 52-year-old woman. Swelling was recognized from the mandibular right molar to the right ramus. A multi [ocular radiolucent area including an impacted tooth was present in the posterior part of the swelling and a radiopaque area with a honeycomb appearance was seen in the anterior part. After the diagnosis of DA, resection of the mandible and reconstruction with an iliac bone graft were performed. Histologically, the anterior lesion showed microscopic features of DA, and the posterior lesion showed those of plexiform ameloblastoma. We discussed DA and hybrid DA by comparing our case with previously reported cases. We conclude that the diagnosis and treatment of DA require careful consideration.

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