Objective To investigate the changes of lumbar bone histomorphometry after exposure to low frequency pulsed electromagnetic fields (PEMFs), and to further understand the effect of PEMFs on osteoporosis (OP) in ovariectomizedOP rats. Methods Sixty-six 3-month-old Sprague Dawley rats were randomly divided into 4 groups: group A(n=12), groupB (n=12), group C (n=12), and group D (n=30). In group A, the ovaries were not resected as sham-ovariectomy; in groupsB, C, and D, the ovaries were resected. At 12 weeks after ovariectomy, the rats were exposed to PEMFs at 8 Hz, 3.8 mT, and 40 minutes/ day for 30 days in group B; the rats were administered with premarin [0.065 mg/(kg·d) by gavage for 30 days] in group C; in group D, the rats were housed as ovariectomy control. The hair and activity of rats were observed; the levels of serum estradiol were determined. At 30 days after intervention, all rats were sacrificed to harvest the L4 vertebrae for bone histomorphometry. Results General observation showed hair loss and decreased activity in group D, and no abnormal appearances in groups A, B, and C. The level of serum estradiol in group A was significantly higher than that in group D [(54.93 ± 23.52) pg/mL vs. (31.99 ± 23.45) pg/mL] (t=2.345, P=0.029). Histological observation showed thinness of sclerotin, bigger medullary cavity, and sparse and thinner bone trabecula in group D; uniform bone trabecula with no breakage in groups A, B, and C at 30 days after intervention. The ratio of trabecular bone area in group B was significantly higher than that in group D (P lt; 0.05); it was higher than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular thickness in group B was significantly higher than that in group D (P lt; 0.05), but it was lower than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular number in group B was significantly lower than that in group D (P lt; 0.05), but it was higher than that in groups A and C, showing no significant difference (P gt; 0.05). The trabecular separation in group B was higher than that in group D and lower than that in groups A and C, showing no significant difference (P gt; 0.05). Conclusion PEMFs at 8 Hz and 3.8 mT can significantly improve the character of bone microstructure in ovariectomized OP rats, increase the ratio of bone trabecular area and trabecular thickness, and decrease the trabecular number.
Objective To investigate the expression of transforminggrowth factor β1(TGF-β1) and insulin-like growth factorⅠ(IGF-Ⅰ)in new bone after low frequency micromovement. Methods Fifteen female sheep from Shandong province were involved in the study and their bilateral tibias transversely osteotomized in the middle shafts with a defect of 2 mm.The hind limbs were fixed with unilateral external fixators connected to a controlled micromovement device. Ten days after osteotomy, one hind limb of each sheep randomlywas selected to perform micromovement at an amplitude of 0.25 mm and a frequency of 1 Hertz, 30 min a day for 4 weeks ( micromovement group). The other hindlimb served as the control group. Five sheep were sacrificed at 3,4 and 6 weeks after osteotomy, respectively, and specimens were harvested for detecting the expression of TGF-β1 and IGF-Ⅰby immunohistochemistry and RT-PCR. Results Immunohistochemistry: In the third postoperative week in the micromovement group, the expression of TGF-β1 was detected in different areas of new chondrocytes at the margin of callus, mainly in proliferating area, and IGF-Ⅰexpressed in osteoblasts at the margin of endochondral ossification area, calcified and mature chondrocytes and osteocytes. There was seldom expression ofIGF-Ⅰ and little expression of TGF-β1 in the corresponding area in the control one. In the 4th postoperative week in the micromovement group, theexpression of TGF-β1 diminished gradually with the mature of new bone and be located in extracellular matrix and osteoblasts around ossified areas; The expression ofIGF-Ⅰ reached the peak and be located mainly in osteoblasts of new bone surface, maturing osteocytes and calcifing osteoid. But there was little expression of them in the control group. In the sixth postoperative week in the micromovement group, there was a little expression of IGF-Ⅰ expression but little expression of TGF-β1; there was nearly no expression of them in the control group. In the micromovement group, the absorbance values of TGF-β1 at 3 and 4 weeksand of IGF-Ⅰat 3, 4 and 6 weeks were significantlyhigher than those in control group（P＜0.05）. RTPCR: In the third and fourth postoperative weeks in the micromovement group, there was higher expression of mRNA of TGF-β1 and TGF-I than those in control group; in the sixth postoperative week, the expression diminished gradually, but was higher than that in control group. The absorbance values of TGF-β1 at 3 and 4 weeks and IGF-Ⅰat 3, 4 and 6weeks were significantly higher than those of control group（P＜0.05）. Conclusion Low frequency and controlled micromovement in the early stage of the fracture healing can promote the expression of TGF-β1 and IGF-Ⅰ.They worked together to regulate the process of the endochondral ossification, while in the late stage the differentiation of osteocytes and mineralization of osteoid were regulated mainly by IGF-Ⅰ, which played an important role in regulating the cell biological behavior during micromovement.
Objective To systematically review the efficacy of low-frequency repetitive transcranial magnetic stimulation (rTMS) compared with sham therapy for the treatment of major depressive disorder. Methods The Cochrane Library, Medline, EMbase, CBMdisk, CNKI and VIP were searched through computer from 1985 to 2011. The review included RCTs comparing the treatment efficacy of low-frequency rTMS located on right dorsolateral prefrontal cortex (DLPFC) with sham stimulation in the patients suffering major depressive disorder. The quality of the included RCTs was strictly evaluated and the data were extracted by two reviewers independently. The extracted data were analyzed by RevMan 4.2. Results Among seven double-blinded RCTs involving 234 patients included, 1 was A level in quality, 5 were B level, and 1 was C level according to the outcomes of quality evaluation. The results of Meta-analysis indicated that low frequency rTMS was superior to sham stimulation in remission rates after two weeks’ treatment (RR=3.11, 95%CI 1.56 to 6.19). Additionally, low frequency rTMS was lower than the sham stimulation in the scores of HDRS and MADRS (WMD= –6.41, 95%CI –9.32 to –3.50, and WMD= –5.27, 95%CI –9.08 to –1.46, respectively). But no significant difference in response rates between the low prequency rTMS group and the sham group was found (RR=1.72, 95%CI 0.74 to 4.01). There were no severe and intolerable side effects reported in these seven studies. Conclusion The low frequency rTMS as a non-invasive and safe technique may appear to be effective for the treatment of major depressive disorder according to the positive results but the conclusion is not definite because of negative results. This review suggests that parameters could be sited as frequency: 1 Hz, intensity: 90%-110% motor threshold (MT), location: right DLPFC and duration: 2 weeks. Nevertheless, further multicenter and high quality studies are needed before it is used as a first-line treatment for major depressive disorder.
目的 比较低频与高频探头超声对急性阑尾炎的诊断价值。 方法 对2010年1月－2011年6月120例急性阑尾炎的手术病理结果与超声检查结果进行回顾性分析，比较低、高频探头超声对急性阑尾炎的诊断价值。 结果 120例急性阑尾炎中，通过低频探头超声检出67例（55.8%），通过高频探头超声检出105例（87.5%）；单纯性阑尾炎以及化脓性和坏疽性阑尾炎高频探头超声检出例数明显大于低频探头超声，差异有统计学意义（P＜0.05）；阑尾周围脓肿低、高频探头超声均全部检出。 结论 高频探头超声对急性阑尾炎的检出率高于低频探头超声，但二者各有所长，在临床中联合应用能有效提高急性阑尾炎的超声诊断符合率。
【摘要】 目的 观察低频超声（20 kHz）辐照联合静脉注射微泡造影剂SonoVue对裸鼠前列腺癌（Du145）移植瘤的抑瘤效应，并探讨其可能的抑瘤机制。 方法 通过细胞移植和瘤块移植方法建立24只裸鼠前列腺癌Du145移植瘤模型，随机分为超声微泡组、单纯超声组、单纯微泡组和对照组，每组各6只。超声微泡组：尾静脉注射0.2 mL SonoVue的同时对瘤体行20 kHz超声辐照，辐照强度200 mW/cm2；单纯超声组：尾静脉注射生理盐水0.2 mL，同时超声辐照2 min；单纯微泡组：尾静脉注射SonoVue 0.2 mL同时行假照，各组均隔天1次，共3次，对照组不做任何处理。治疗后测量瘤体大小，绘制瘤体生长曲线，计算抑瘤率。首次治疗后14 d剥离瘤体，通过光学显微镜、电子显微镜观察肿瘤组织病理改变。免疫组织化学方法观察CD34阳性染色血管，计算肿瘤微血管密度（micro vessel density，MVD），比较各组间MVD的差异。 结果 24只裸鼠均成功植瘤。治疗后超声微泡组瘤体体积均数明显小于其他3组（Plt;0.05），抑瘤率为62.7%。光学显微镜下超声微泡组瘤体组织大部分损伤坏死，电子显微镜下超声微泡组肿瘤内微血管的内皮细胞损伤，线粒体肿大，基底膜断裂。超声微泡组瘤体内CD34阳性染色微血管数减少，其MVD值显著低于其他各组。 结论 20 kHz低频超声辐照联合微泡造影剂SonoVue可有效抑制裸鼠人前列腺癌移植瘤的生长，其抑瘤机制可能是通过超声空化效应破坏肿瘤的微血管实现的。【Abstract】 Objective To investigate the anti-tumor effect induced by low-frequency ultrasound (20 kHz) radiation combined with intravenous injection of microbubbles on human prostate carcinoma xenograft in nude mice, and to discuss its probable mechanism. Methods Human prostate carcinoma xenograft model in 24 nude mice were established with human prostate carcinoma Du145 cells inoculation and sub-graft through mice, which were randomly divided into ultrasound+microbubble, ultrasound, microbubble, and control group, with 6 mice in each group. In the ultrasound+microbubble group, 0.2 mL SonoVue was injected intravenously, followed by 20 kHz ultrasound exposure of 200 mW/cm2 at every other day for 3 times totally. Mice in the ultrasound group and the microbubbles group were only treated with ultrasound radiation and microbubbles injection, respectively. The volume of gross tumors was measured, and tumor growth curve was drawn. The ratio of anti-tumor growth was calculated. The mice were sacrificed 14 days after the last ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. CD34 positive vessels were counted in all the tumor slices by immunohistochemistry, and the micro-vessels density（MVD）of the tumor was also calculated. Results Du145 prostate tumor model was successfully established in all the mice. The average gross tumor volume of the ultrasound+microbubble group was significant lower compared with the other two groups after treatment (Plt;0.05), and the ratio of anti-tumor growth was 62.7%. Histological examination showed signs cell injury in the ultrasound+microbubble group. Electron microscopic examination revealed that the endothelium of vessels in the tumor was injured. The amount of CD34 positive vessels and MVD of the ultrasound+microbubble group was less than that of the other two groups. Conclusion The low-frequency ultrasound of 20 kHz exposure combined with microbubbles can be used to ablate human prostate carcinoma xenograft in nude mice, which is probably realized through micro-vessels destroyed by cavitation effect of ultrasound.
ObjectiveTo compare the clinical effects of pulsed electromagnetic fields (PEMFs) with oral alendronate in the treatment of postmenopausal osteoporosis. MethodsFourty patients diagnosed to have postmenopausal osteoporosis (OP) from September 2009 to September 2010 were included in our study. They were randomly divided into the experimental group and the control group. All patients were administered the same basic drugs:Caltrate 600 mg and Alfacalcidol 0.5 μg per day. For the experimental group, PEMFs were offered 6 times per week for 5 weeks (30 times in total), and patients in this group were followed up for 12 weeks. For the control group, alendronate was given at a dose of 70 mg per week for 12 weeks. Bone mineral density (BMD), visual analogue scale, and manual muscle testing (MMT) scale were evaluated before, 1 week, 5 weeks, and 12 weeks after intervention. ResultsIncreasing of BMD, pain relieving, and improvement of MMT had a trend of increasing values after 5 weeks of treatment in the experimental group (P<0.05), but there was no significant difference between the two groups (P>0.05). However, there was a significant difference between the two groups in patients' lower back muscle strength after treatment (P<0.05). ConclusionPEMFs have the same effect as alendronate in pain relief, and bone mass and muscle strength improvement, and are even advantageous in increasing back muscle strength compared with alendronate.
We investigated the baseline brain activity level in patients with major depressive disorder (MDD) by amplitude of low-frequency fluctuation (ALFF) based on resting-state functional MRI (fMRI). We examined 13 patients in the MDD group and 14 healthy volunteers in the control group by resting-state fMRI on GE Signa 3.0T. We calculated and compared the ALFF values of the two groups. In the MDD group, ALFF values in the right medial prefrontal were higher than those in control group, with statistically significant differences (P<0.001). ALFF values in the left parietal in the MDD group were lower than those in control group with statistically significant differences (P<0.001). This resting-state fMRI study suggested that the alteration brain activity in the right medial prefrontal and left parietal ALFF contributed to the understanding of the pathophysiological mechanism of MDD patients.
Aiming at the single treatment and the design separation between treatment and assessment in electrotherapy equipment, a kind of system including low-intermediate frequency treatment and efficacy evaluation was developed. With C8051F020 single-chip microcomputer as the core and the circuit design and software programming used, the system realized the random switch of therapeutic parameters, the collection, display and data storage of pressure pain threshold in the assessment. Experiment results showed that the stimulus waveform, current intensity, frequency, duty ratio of the system output were adjustable, accurate and reliable. The obtained pressure pain threshold had a higher accuracy (<0.3 N) and better stability, guiding the parameter choice in the precise electrical stimulation. It, therefore, provides a reliable technical support for the treatment and curative effect assessment.
To enhance speech recognition, as well as Mandarin tone recognition in noice, we proposed a speech coding strategy called zero-crossing of fine structure in low frequency (LFFS) for cochlear implant based on low frequency non-uniform sampling (LFFS for short). In the range of frequency perceived boundary of human ear, we used zero-crossing time of the fine structure to generate the stimulus pulse sequences based on the frequency selection rule. Acoustic simulation results showed that although on quiet background the performance of LFFS was similar to continuous interleaved sampling (CIS), on the noise background the performance of LFFS in Chinese tones, words and sentences were significantly better than CIS. In addition to this, we also got better Mandarin recognition factors distribution by using the improved index distribution model. LFFS contains more tonal information which was able to effectively improve Mandarin recognition of the cochlear implant.