Low-intensity pulsed ultrasound enhances palatal mucosa wound healing in rats.

PURPOSE: Low-intensity pulsed ultrasound (LIPUS) has been used in fracture treatment to shorten the time needed for biological wound healing. However, the influence of LIPUS exposure on oral wound healing has not been sufficiently investigated. This study was conducted to evaluate low-intensity pulsed ultrasound on wound healing in palatal excisional wounds of rats. METHODS: Excisional wounds, 5 mm in diameter, were made in the center of the palate of rats. Animals were divided into four experimental and control groups (1-week after LIPUS exposure, 1-week control, 2-week after LIPUS exposure, and 2-week control). The affected area in the experimental group was exposed to LIPUS, daily frequency: 3 MHz, intensity: 160 mW, exposure time: 15 min. Specimens were fixed in 10% neutral formalin solution immediately after sacrifice. The wound was measured histologically. RESULTS: Wound width in the LIPUS group tended to be smaller than that of the control group. The experimental group in both 1-week and 2-week groups showed that unhealed areas were significantly smaller by LIPUS than those in the control groups (P<0.05). CONCLUSION: Our results suggest that the use of LIPUS on palatal excisional wounds was effective in promoting epithelial and connective tissue closure.

Cementoblast response to low- and high-intensity ultrasound.

OBJECTIVE: It has been shown that ultrasound stimulation accelerates repair of orthodontically induced root resorption. However, the mechanism of such adaptive change is still unclear. The purpose of this study was to evaluate pulsed ultrasound on the differentiation-potential and cementoblast-mediated osteoclastogenesis using a cementoblastic cell line. DESIGN: Cultured cementoblasts (murine cementoblastic cell line, OCCM-30) were subjected to ultrasound exposure (frequency = 1 MHz; pulsed 1:4; spatial average temporal average intensities=30 or 150 mW/cm(2)) or sham exposure for 15 min per day. Expression levels of alkaline phosphatase (ALP), type I collagen (COL-I), osteoprotegerin (OPG) and receptor activator of nuclear factor small ka, CyrillicB ligand (RANKL) mRNAs were analysed by a real-time PCR analysis. Furthermore, ALP activity, collagen synthesis, and protein levels of OPG and RANKL were examined after 6-day ultrasound exposure. RESULTS: Real-time PCR analysis indicated that, irrespective of the intensity, single ultrasound exposure increased the expression of transcripts for COL-I and ALP after 24h; the expression of OPG and RANKL also increased after 1 and 4h, respectively. Cultured cementoblasts receiving ultrasound stimulation for 6 days showed a significant (p<0.05 or 0.01) increase in cell number and collagen synthesis. ALP activity and OPG synthesis were also significantly (p<0.05) upregulated by ultrasound stimulation with 150 mW/cm(2). CONCLUSIONS: These results demonstrated that ultrasound stimulation especially with 150 mW/cm(2) might be a better candidate as a medical remedy to protect against root resorption and/or accelerate its repair.

[Study of genotype frequencies of ANP 664G/A polymorphism in normal subjects and CVD patients, and its association with plasma ANP levels].

Atrial natriuretic peptide (ANP) plays a crucial role in regulating body fluid volume and blood pressure, by promoting natriuresis and vasodilatation and by inhibiting the renin-angiotensin system. Plasma levels of ANP are elevated in heart failure and hypertension, and ANP is thus believed to be involved in the pathogenesis of cardiovascular disorders. Previous case-control studies have shown that a single nucleotide polymorphism in the first exon of ANP gene, 664G/A, is associated with a risk of cerebrovascular disease (CVD) in white populations. Plasma ANP levels, however, were not evaluated in these studies in relation to the 664G/A, although the nucleotide substitution causes an amino-acid change in the propeptide of ANP. In this study, we analyzed the genotype frequencies of the 664G/A in Japanese patients with CVD (n = 199) and age- and gender-matched control subjects(n = 176). Genotypes with the 664A allele in the Japanese control subjects (G/A and A/A 12.5%) were apparently more frequent compared to the published frequency of the white control population (G/A and A/A 6.6%, p = 0.0437). Genotypes with the 664A allele, however, were not significantly different between our CVD patients(15.1%) and controls (12.5% p = 0.4714). In the control group (n = 137), the mean plasma ANP levels were not different between the 664G/G (15.7 +/- 10.7 pg/ml) and 664G/A genotypes (15.6 +/- 6.8 pg/ml, p = 0.9708). These results suggest that there is a racial difference in the allele frequency of 664G/A, and that this polymorphism may not be a major risk factor for CVD in the Japanese, nor is it a major determinant of plasma ANP level.