新版E-tracking技术在颈动脉弹性功能定量研究中的应用

目的 探讨新版血管回声跟踪（ET）技术在定量评价颈动脉弹性功能中的价值。方法研究对象为有颈动脉斑块并有相应症状（症状组）、有颈动脉斑块但无相应症状（斑块组）、颈动脉无斑块形成但有高危临床表现（高危组）及健康查体者（对照组）,采用新版ET技术对其颈动脉血管弹性功能进行测定,参数包括僵硬度（B）、压力应变弹性系数（Ep）、顺应性（AC）、增大指数（AI）、脉搏波传导速度（PWVβ）、收缩期内径（Ds）和舒张期内径（Dd）,并对症状组和斑块组上述参数进行相关性分析。结果症状组及斑块组双侧颈动脉弹性指标差异无统计学意义,但其EO、β、PWVβ、AI及IMT显著高于高危组及对照组,AC显著低于高危组及对照组（P〈0．05、0．01）;症状组及斑块组PWVβ与β、EO和IMT呈正相关,与AC呈负相关,AI与EO、β、AC和IMT无明显相关。结论新版ET技术可客观准确反映颈动脉血管的弹性变化,为早期预防和疗效评价提供重要信息。     

会阴体长度及弹性度测量在分娩中的应用

目的探讨分娩期测量会阴体长度及弹性度的应用价值。方法将320例经阴分娩的足月初产妇随机分为两组,观察组测量会阴体长度及弹性度并予相应干预,对照组常规处理。结果与对照组比较,观察组会阴侧切率、裂伤发生率、出血量、疼痛评分明显降低,切口甲级愈合率升高,住院时间缩短（P均〈0．01）。结论分娩期测量会阴体长度和弹性度并予相应干预,可降低会阴切开术及软产道严重损伤。     

The pharmacokinetics and cardiovascular effects of high-dose articaine with 1:100,000 and 1:200,000 epinephrine

OBJECTIVES: The authors conducted a randomized, double-blind, two-way crossover clinical trial to compare the pharmacokinetics and cardiovascular effects of 11.9 milliliters of 4 percent articaine hydrochloride (HCl) plus 1:100,000 epinephrine (A100) with those of 11.9 mL of 4 percent articaine HCl plus 1:200,000 epinephrine (A200). METHODS: During two testing sessions, the authors administered injections of A100 and A200 over a seven-minute period (in one-cartridge doses unless otherwise noted): maxillary right first molar infiltration, maxillary left first molar infiltration, maxillary right first premolar infiltration, maxillary left first premolar infiltration, right inferior alveolar injection, left inferior alveolar injection, right long buccal infiltration (one-half cartridge) and left long buccal infiltration (one-half cartridge). They analyzed venous blood samples for articaine levels. They used noninvasive acoustic tonometry to measure a variety of cardiovascular parameters over a two-hour period. RESULTS: Plasma concentration curves of articaine over time were similar for both solutions, with peak concentrations and times to maximum concentration being 2,037 nanograms per milliliter and 22 minutes for A100 and 2,145 ng/mL and 22 minutes for A200. At the 10-minute point, the mean systolic blood pressure and heart rate were significantly elevated (P < .05) with A100 versus A200. CONCLUSIONS: Maximum dose recommendations for the A100 solution also can be applied to the A200 solution. A200 produces less cardiovascular stimulation than does A100. CLINICAL IMPLICATIONS: A200 is as safe as A100, and may be preferable to A100 in patients with cardiovascular disease and in those taking drugs that reportedly enhance the systemic effects of epinephrine.     

Age-related changes in hardness and modulus of elasticity of dentine

OBJECTIVES: Little knowledge has been clarified about the relationship between the morphological and physical changes of dentine during aging. The purpose of this study was to clarify the modulus of elasticity and hardness related to the morphological changes of dentine by aging using a transmitted light microscope (TLM) and a nano-hardness tester (NHT). METHODS: Aged human molars and young third molars were used. The dentine morphology was observed under a TLM. The hardness and Young's modulus of elasticity related to the morphologic study were evaluated with an NHT. RESULTS: The thickness of mantle dentine and globular dentine of aged teeth were less than that of young teeth. Transparent dentine was observed only underneath the attrition of young teeth. Reactionary tertiary dentine formed and a "dark zone" was found at the junction between physiologic secondary and reactionary dentine only in aged teeth. At the mantle dentine, hardness and modulus of elasticity of aged dentine were higher than those of young dentine. The reactionary dentine in aged teeth and newly developed secondary dentine in young teeth demonstrated lower modulus of elasticity and hardness than those of other circumpulpal dentine. Relatively low modulus of elasticity and hardness were observed at the zone between secondary and reactionary dentine. CONCLUSIONS: Changes in dentine due to aging resulted in transformation of morphological features causing changes to their hardness and modulus of elasticity at the explicit areas such as the increase of hardness and modulus of elasticity at mantle dentin and the reduction of these properties at the "dark zone" that found in aged teeth.     

Changes in the soleus muscle architecture after exhausting stretch-shortening cycle exercise in humans

This study focused on the architectural changes in the muscle–tendon complex during the immediate and secondary (delayed) reductions of performance (bimodal recovery) caused by an exhaustive rebound type stretch-shortening cycle (SSC) exercise. The isometric plantar flexor torque during maximum voluntary contraction (MVC) was measured together with recording of electromyography (EMG) and ultrasonography from the soleus muscle before (BEF), after (AFT), 2 h (2H), 2 and 8 days (2D, 8D) after the SSC exercise (n = 8). The performance variables (MVC torque and EMG activation) followed the bimodal recovery patterns. This was not the case in the changes of the fascicle length and muscle thickness. The relative torque changes in MVC correlated positively (R = 0.78, P = 0.02) to the corresponding averaged EMG changes between BEF and 2H (BEF → 2H); the significance disappeared in the comparison between 2H and 2D (2H → 2D), during which period MVC showed a secondary reduction. The relative torque changes in MVC showed no correlation with the changes in muscle thickness between BEF–2H. However, this correlation between 2H–2D was negative (R = –0.85, P < 0.01). The fascicle shortening/average EMG ratio in MVC increased at 2H, and then decreased more at 2D than 2H (P < 0.05). Thus, the secondary performance decline was not related to the corresponding EMG reduction but to the increased muscle thickness, which peaked at 2D. The results suggest clearly that the secondary decline in MVC could be related to the increase in muscle volume.     

Fluctuations in carotid arterial distensibility during the menstrual cycle do not influence cardiovagal baroreflex sensitivity

Aim: Fluctuations in autonomic nervous functions throughout the menstrual cycle and the underlying mechanism concerning them are not well known. This study was designed to test the hypothesis that fluctuations in cardiovagal baroreflex sensitivity (BRS) throughout the menstrual cycles of young women are due to fluctuations in carotid arterial distensibility. Methods: In eight eumenorrhoeic healthy young women (18–24 years), we determined the variations in the carotid arterial distensibility coefficient (DC; via simultaneous ultrasonography and applanation tonometry), cardiovagal BRS (phase IV of the Valsalva manoeuvre and the sequence method; up‐ or down‐sequence spontaneous BRS), and serum oestradiol and progesterone concentrations at five points in the menstrual cycle (menstrual = M, follicular = F, ovulatory = O, early luteal = EL, and late luteal = LL). Results: Serum oestradiol and progesterone levels were consistent with the predicted cycle phases. Carotid arterial DC fluctuated cyclically, increasing significantly from the M (52.4 ± 4.9 × 10^?3 kPa^?1, mean ± SE) and F (52.7 ± 4.4) phases to the O (57.6 ± 4.4) phase and declining sharply in the EL (46.0 ± 4.0) and LL (45.1 ± 3.0) phases (F = 6.37, P < 0.05). Contrary to our prediction, however, cardiovagal BRS by the Valsalva manoeuvre (P = 0.73) or sequence method (up‐sequence spontaneous BRS; P = 0.84: down‐sequence spontaneous BRS; P = 0.67) did not change significantly during the menstrual cycle. Conclusion: The results suggest that, although carotid arterial distensibility fluctuates with the changes in ovarian hormone levels that occur during the menstrual cycle, the fluctuations in carotid arterial distensibility do not influence cardiovagal BRS.     

坎地沙坦对高血压患者大动脉弹性影响的对照观察

目的:评价坎地沙坦在降压同时对大动脉弹性的改善效果。方法:选择48例高血压患者,随机分成坎地沙坦治疗组和氢氯噻嗪对照组,每组各24例,分别给予坎地沙坦(8mg.d-1)及氢氯噻嗪(25mg.d-1)行降压治疗,如果血压下降不理想则两组均加用非洛地平(5mg.d-1),在治疗前及治疗20周以后分别检测血压及颈-股动脉脉搏波传导速度(C-FPWV)值。结果:在两组患者血压下降水平无明显差异的情况下(P>0.05),坎地沙坦组治疗后的C-FPWV值较氢氯噻嗪组有明显下降(P<0.05)。结论:坎地沙坦能明显的改善大动脉弹性,这种改善作用与降压本身及降压之外的因素均有关。     

超声弹性成像评价大鼠脂肪肝分级的应用价值

目的探讨实时超声弹性成像评价大鼠脂肪肝分级的应用价值。方法建立大鼠脂肪肝模型,分别于造模第6、8、10、12、14周随机选取大鼠进行超声弹性测量。在超声弹性成像模式下获取参照物与大鼠肝脏的应变比（B/A）,然后处死大鼠,取出肝脏,进行病理切片并进行脂肪肝的分级诊断。最后将所获取的大鼠肝脏弹性数据与病理显示的脂肪浸润程度分级进行相关性分析。结果实验最终获得40只大鼠的超声弹性数据和病理结果,不同脂肪肝病理分级的B/A两两比较差异均有统计学意义（P均〈0.05）;B/A与其病理分级间呈相关性（r=0.88,P〈0.01）。结论实时超声弹性成像为无创定量诊断脂肪肝提供了新方法,将在临床中有良好的应用前景。