Objective: This study in rat genioglossus muscle (GG) was designed to test the hypothesis that the effects of estrogen are at least in part, meditated directly by the estrogen receptors (ERs) of muscle. Design: Eighty-eight-week-old female Sprague-Dawley rats were randomly assigned to five groups: (1) normal animals (Normal); (2) sham operation animals (Sham); (3) ovariectomized animals without estrogen replacement (OVX); (4) ovariectomized animals with olive oil replacement (OVX+O); (5) ovariectomized animals with 17b-estradiol replacement (OVX+E2). Six weeks later, GG was assessed in vivo for contractile properties and further analysis for ERs expression was carried out including real-time quantitative RT-PCR, immunohistochemistry and Western blotting. Results: The maximal twitch tension, 70%-decay time and fatigue index of GG decreased significantly in OVX group when compared with Normal group (P<0.05, P<0.05, P<0.05). However, all the three parameters reversed in OVX+E2 group especially fatigue index. Further analysis showed a clear expression of ERa and ERb in rat GG. The expression of both ERa protein and ERa mRNA was both significantly decreased in OVX group (P<0.05) and recovered back to previous level after receiving 17b-estradiol replacement (P<0.05). But neither ERb protein nor ERb mRNA was regulated by estrogen deprivation and replacement. Conclusion: The results demonstrated that the contractility of GG was accentuated by estrogen. Moreover, these effects were at least in part, meditated directly via regulation of the expression of ERa. It might contribute to the protective effects of estrogen on the patency of upper airway and the pathogenesis of obstructive sleep apnea hypopnoea syndrome.

This study was designed to investigate the effects of oestrogen on sarcoplasmic reticulum (SR) Ca2+-ATPase activity and gene expression in ovariectomised rats under the condition of chronic intermittent hypoxia (CIH). Thirty-two female Sprague-Dawley rats were randomly divided into four groups: the normal control group (NC), the CIH group (CIH), the CIH-ovariectomised group (CIH+OVX), and the group of CIH-ovariectomised rats receiving estradiol replacement (CIH+OVX+E2). Rats in the latter three groups were exposed to CIH for 5 weeks. The animals were killed before genioglossus (GG) was rapidly excised, and their body and uterus mass were determined. Estradiol level was detected by radioimmunoassay. SR Ca2+-ATPase (SERCA) activity was observed by detecting inorganic phosphorus ion, and the SERCA mRNA level was measured using real-time quantitative polymerase chain reaction (real-time PCR). It was found that, compared with the NC group, the SERCA activity and mRNA level were remarkably reduced (p<.01) in the CIH group. And compared with the CIH group, the SERCA activity and mRNA level were also significantly reduced (p<.01) in the CIH + OVX group. Meanwhile, the SERCA activity and mRNA level significantly increased (p<.01) in the CIH+OVX+E2 group compared with the CIH+OVX group, but lower than those in the NC group (p<.01). The results showed that CIH could reduce the SERCA activity and mRNA expression, and oestrogen-deficiency could exacerbate this effect; whilst estradiol replacement can partially reverse the effect of CIH in ovariectomised rats.

Introduction: Mandibular advancement appliances have been used for years in the treatment of obstructive sleep apnea (OSA). However, it has not been completely clarified how the upper airway changes after mandibular advancement. The purpose of this study was to examine the effects of mandibular advancement on anatomic structures of the upper airway in patients with OSA by magnetic resonance imaging. Methods: Eleven OSA patients (aged 48.0 5.86 years) with apnea and hypopnoea index values of 46.8 21.47 participated in this study. A series of magnetic resonance images was taken for each subject with a custom-made device in the mouth that could advance the mandible by 0, 2, 4, 6, and 8 mm. In addition, an image with the mandible in centric occlusion was taken. Changes in cross-sectional area, sagittal diameter, transverse diameter, and cross-sectional shape in the whole upper airway and the different regions were compared between the various amounts of mandibular advancement. Results: The minimum and mean cross-sectional area of the velopharynx and the mean transverse diameter of the velopharynx increased significantly (P 0.0001 and P 0.0016, respectively) during mandibular advancement. However, no statistically significant changes (P 0.05) in sagittal diameter were found between the various mandibular advancements. In cross-sectional shape, a significant increase (P 0.0066) was found when the mandible was advanced to 8 mm from 0 mm or centric occlusion position. Conclusions: Mandibular advancement significantly increases the cross-sectional area of the velopharynx in awake OSA patients. This contributes to the increase in its transverse dimension rather than the sagittal, thus resulting in the change of its shape.

This investigation was designed to examine whether short-term administration of sex hormones could produce changes in contractile properties and the sarcoplasmic reticulum Ca2+-ATPase (SERCA) function in genioglossal muscle (GG) of aged male rats. Twenty-four aged male rats were randomly divided into three groups to receive an intramuscular injection of either 0.1 mg/kg oestrogen (group A), 2.5 mg/kg testosterone (group B), or 0.2 ml sterile peanut oil (group C, control), twice a week, during 4 weeks. After hormone treatment, in vivo isometric contractile properties were determined using surgically prepared GG muscles with platinum electrodes for stimulation of the medial branch of the hypoglossus nerve. Sarcoplasmic reticulum Ca2+-ATPase activity was measured in muscle homogenates by detecting the amount of inorganic phosphorus ion released in a standard coupled enzyme assay. SERCA1 mRNA level was observed using a real-time quantitative reverse transcription-polymerase chain reaction (Q-RT-PCR). It was found that, compared with group C, testosterone treatment decreased the fatigue resistance in GG muscles (p<.05), whereas no change was observed in the isometric twitch (Pt) and tetanic tension (P0) (p>.05). By contrast, in oestrogen treated GG muscles, no significant modification was found either in the contractile or in endurance properties (p>.05). The change in GG fatigue resistance of group B was associated with a marked decrease in SR Ca2+-ATPase activity when compared with that of the control group (p<.01). Furthermore, SERCA1 mRNA level was also down regulated in group B (p<.05). No prominent differences in SR Ca2+-ATPase activity and SERCA1 mRNA expression existed between group A and group C (p>.05). The present results show that exogenous testosterone produces more pronounced changes in GG muscle fatigue resistance than oestrogen does by acting at SR Ca2+-ATPase activity and SERCA gene expression.

目的：调查正畸治疗导致牙根外吸收的发病情况，分析其临床特征及相关因素。方法：随机选择经直丝弓矫治技术完成的病例230例，以Levander根吸收分级法对患者全颌曲面断层片进行分析，评估矫治前后中切牙至第一磨牙的根吸收情况。结果：正畸治疗后根吸收发生率明显升高，根吸收均值（root resorption after treatment, RRAT）及根吸收增加量均值（increment of root resorption, IRR）表现为上切牙最高，拔牙组高于未拔牙组，异常根形态组高于正常根形态组。结论：正畸治疗可提高根吸收发生几率，并加重根吸收程度，此可能与拔牙与否、牙位、根形态及治疗前牙根吸收程度有关。