急性弓形虫感染对雄性小鼠睾丸生精功能影响的初步研究

目的:探讨弓形虫急性感染对雄性小鼠睾丸生精功能的影响。方法:将26只成年雄性小鼠随机均分为感染组和正常对照组;感染组腹腔注射0.3ml1×103/ml弓形虫速殖子,感染小鼠睾丸,正常组腹腔注射等量生理盐水,两组睾丸制成直接印片及病理切片,观察小鼠生精细胞的病理变化及弓形虫侵入生精细胞情况。同时比较两组睾丸乳酸脱氢酶同工酶、精子密度、精子活动率、精子畸形率。结果:感染组睾丸乳酸脱氢酶同工酶、精子密度、精子活动率、精子畸形率分别为53.19±18.04、(15.01±2.42)×106/ml、(8.26±2.57)%、(17.69±11.91)%,正常组为68.71±17.79、(23.87±6.66)×106/ml、(13.21±2.82)%、(11.30±6.60)%,两组比较差异均有显著性(P<0.05)。结论:弓形虫感染对雄性小鼠睾丸生精功能有一定的影响。     

小鼠单侧睾丸损伤后环孢素A对Fas系统的影响

目的 :研究昆明小鼠 (KM小鼠 )单侧注射冰乙酸致睾丸损伤后环孢素A(CsA)对对侧睾丸生精功能和Fas系统表达的影响。　方法 :6 0只KM小鼠随机分为 4组 :A组为对照组 ,B组为单侧睾丸损伤组 ,C组为单侧睾丸损伤后 6h切除损伤睾丸组 ,D组为单侧睾丸损伤后 6h内开始腹腔注射CsA组。 4周后取对侧附睾尾 ,计数精子及其活率 ,对侧睾丸作石蜡切片苏木精 伊红染色和免疫组化链霉素抗生物素蛋白过氧化物酶连结 (SP)法检测Fas和FasL的表达。　结果 :D组附睾尾精子和活率计数显著高于B组 (P <0 .0 5 ) ,D组的FasL和Fas较B组显著降低 (2 4 .3± 7.0vs37.8± 5 .8和 17.8± 4 .3vs32 .4± 3.6 ,P <0 .0 5 )。　结论 :KM小鼠单侧睾丸损伤后CsA可以通过抑制Fas和FasL的表达 ,降低生精细胞凋亡 ,维持生精功能的稳定     

Dctn1在小鼠睾丸和精子中的定位及在变形过程中的功能初探

目的:探讨动力蛋白激活蛋白1(Dctn1)在小鼠精子变形过程中的作用。方法:通过Western印迹及间接免疫荧光技术分析Dctn1在小鼠睾丸及精子中的表达和定位。分别运用体外GC2-spd细胞系以及在体两种策略筛选出具有最高干扰效率的Dctn1的小干扰RNA(siRNA),进而应用睾丸网微注射技术,将混有示踪剂(0.4%台盼蓝)的Dctn1 siRNA注射至3周ICR小鼠的生精小管内,对照侧的睾丸注射阴性对照siRNA,正常组为不加任何处理的3周ICR小鼠。在注射后第3周取附睾尾部精子进行形态学分析。结果:Dctn1主要定位于精子的尾部。干涉后Dctn1 siRNA组的精子尾部畸形率为(23.57±0.55)%,明显高于对照组[(12.35±2.29)%,P<0.01,n=3],而正常组精子尾部畸形率为(3.37±0.69)%。结论:Dctn1在精子变形中可能发挥重要作用,它主要影响精子尾部的形成。     

二甲双胍对营养性肥胖大鼠附睾精子质量和睾丸抗氧化能力的影响

目的:观察二甲双胍对高脂饮食诱导的肥胖大鼠附睾精子质量和睾丸抗氧化能力的影响。方法:雄性SD大鼠分为正常对照组和造模组,造模组以高脂饲料喂养8周后,取24只肥胖大鼠随机分为模型对照组、二甲双胍组和普通饲料组,除模型对照组继续高脂饲料喂养外,其余3组普通饲料喂养。12周末,所有大鼠均禁食12 h后处死,检测Lee's指数、睾丸和附睾脏器指数,附睾精子浓度、精子活动率和a+b级精子百分率,睾丸组织匀浆中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)和丙二醛(MDA)含量。结果:Lee's指数模型对照组与其他3组比较显著升高(P<0.01),Lee's指数正常对照组较二甲双胍组升高(P<0.05)。睾丸、附睾、脏器指数模型对照组较其他3组显著降低(P<0.01)。精子浓度、精子活动率和a+b级精子百分率模型对照组与其他3组比较显著降低(P<0.05或P<0.01),正常对照组较二甲双胍组和普通饲料组精子浓度升高(P<0.05)。SOD含量(U/mg prot)模型对照组(90.92±4.06)较正常对照组(101.69±8.49)与二甲双胍组(102.04±10.67)降低(P<0.05)。GSH-Px含量(U)正常对照组(28.32±2.28)较模型对照组(23.49±1.08,P<0.01)、二甲双胍组(25.73±2.14,P<0.05)和普通饲料组(25.77±2.19,P<0.05)升高,模型对照组较二甲双胍组降低(P<0.05)。MDA含量(nmol/mg prot)模型对照组(2.68±0.76)较正常对照组(1.84±0.31,P<0.01)、二甲双胍组(1.88±0.33,P<0.01)和普通饲料组(2.14±0.35,P<0.05)升高。结论:二甲双胍治疗和饮食改善均可提高营养性肥胖大鼠精子质量,改善睾丸组织抗氧化能力。     

鹿藿根4种提取物抗雄性小鼠生育作用比较

目的:比较4种鹿藿根提取物(乙醇提取物、乙酸乙酯提取物、正丁醇提取物及水溶物)的抗生育作用。方法:60只雄性昆明种小鼠分为生理盐水对照组、雷公藤多苷对照组、乙醇提取物组、乙酸乙酯提取物组、正丁醇提取物组及水溶物组,每组10只。各组药物浓度均为1%,雷公藤多苷为0.1%水溶液。每次0.1ml/10g,灌胃,1次/d,连续给药,共11周。在用药10周后,一对一雌雄合笼交配1周。分笼10d后处死雌鼠,观察妊娠率、活胎数、死胎数。11周后处死雄性小鼠观察附睾精子、附睾及睾丸病理变化情况及血清睾酮含量测定。结果:连续用药11周,与生理盐水对照组相比,实验组小鼠妊娠率下降,其中水溶物组最为明显(P<0.05)。雷公藤多苷对照组和水溶组精子明显减少(P<0.05)。组织学观察鹿藿根提取物对精原细胞、初级精母细胞影响不显著。各提取物组血清睾酮差异无显著性(P>0.05)。生理盐水对照组、雷公藤多苷对照组、乙酸乙酯提取物组、正丁醇提取物组、乙醇提取物组及水溶物组的抗精子发生效应积分分别0、(5.3±1.5)、(2.6±1.7)、(2.9±1.2)、(2.2±0.9)、(2.1±1.0)分。结论:4种鹿藿根提取物均有抗生育作用,但水溶物作用更强且对睾丸组织及睾丸生精能力影响较小。     

肾精亏虚对雄性小鼠及其雄性仔鼠生育力的影响

目的:观察肾精亏虚对雄性小鼠及其雄性仔鼠生育力的影响。方法:将30只6周龄雄性昆明小鼠随机均分为正常对照组、模型组和补肾组3组。模型组和补肾组采用房劳加惊恐的复合伤肾法制造肾精亏虚模型。补肾组每天给予0.16ml/10g体重的补肾填精方浓缩液灌胃。正常对照组及模型组予等量生理盐水灌胃,造模并给药21d。从造模结束次日起,所有小鼠与正常动情期雌鼠配对饲养5d后检测其精子密度及活动率。取出雌鼠待其分娩,分别计算各组配对雌鼠妊娠率和每胎生产数(仔鼠总数/妊娠并分娩的雌鼠只数)以评估父代小鼠生育力。雄性仔鼠饲养至6周龄时每组随机取出10只检测其精子密度及活动率。结果:模型组每胎生产数[(7.00±1.73)只]明显比正常对照组[(9.43±1.27)只]和补肾组[(8.80±1.10)只]低(P<0.05);模型组小鼠精子密度[(9.70±1.45)×106/ml]及活动率[(66.72±10.12)%]均明显低于正常对照组[(14.08±1.15)×106/ml,(81.75±3.56)%]和补肾组[(12.20±1.55)×106/ml,(78.55±4.38)%],P<0.01,而正常对照组与补肾组之间则没有差异(P>0.05);模型组仔鼠精子密度[(10.1±1.79)×106/ml]及活动率[(71.86±7.48)%]均低于正常对照组[(15.30±1.83)×106/ml,(79.86±5.68)%]和补肾组仔鼠[(14.20±2.21)×106/ml,(81.92±2.51)%],P<0.05,正常对照组与补肾组仔鼠之间没有差异(P>0.05)。结论:"惊恐、房劳"可以明显降低小鼠生育力,其仔鼠生育力亦可受累。补肾法可以阻断这种损伤的发生。     

弱精子症患者精子X,Y,18号染色体的三色荧光原位杂交分析

目的:利用三色荧光原位杂交方法分析弱精子症患者精子X,Y,18号染色体数目畸变。方法:应用X、Y、18号染色体探针对10例弱精子症患者和5例健康男性进行三色荧光原位杂交实验,检测其精子非整倍体数目畸变情况。结果:计数45547个精子,杂交率99.18%。双体类型为XX18、XY18、YY18、X1818、Y1818。病例组各类双体率分别为(0.124±0.086)%、(0.360±0.380)%、(0.109±0.195)%、(0.342±0.746)%、(0.299±0.564)%。对照组各类双体率为(0.014±0.019)%、(0.090±0.080)%、(0.030±0.031)%、(0.068±0.103)%、(0.075±0.083)%。病例组的非整倍体率9.25%,对照组为2.70%,两者比较,差异有显著性(P(0.01)。结论:弱精子症患者的精子比对照组精子的染色体非整倍体率高,为提供更有效的科学依据,尚需大样本研究。     

中频磁场对小鼠血液及重要脏器的影响

目的探讨中频磁场对小鼠血液指标、重要脏器及生殖系统功能的影响。方法20只雄性昆明小鼠,体重（30±2）g,随机分为辐照组和对照组,每组10只。辐照组小鼠受磁场（40kHz,28mT,2h／d）连续照射7d。第8天检测血常规,取脑、肝、肾、脾及睾丸称重后进行组织分析。另24只雄性昆明小鼠分成4组,每组6只,包括对照组和实验1组（35mT,2h／d）、实验2组（35mT,1b／d）、实验3组（0．18mT,2h／d）,实验组均连续照射7d,然后进行精子活率、精子密度检测。结果辐照组与对照组小鼠血常规及脏器称重结果差异均无显著性（P〉0．05）。病理切片提示脑、肝、肾和脾无病理变化,而睾丸小叶中各级生精细胞均有减少,精子细胞减少且排列紊乱。精子活率对照组为（40．58±7．75）％,实验1组降低至（7．40±1．06）％（q=16．909,P〈0．05）,实验2组降低至（12．26±0．87）％（q=14．432,P〈0．05）,实验3组（37．84±5．52）％与对照组差异无显著性（q=1．396,P〉0．05）。各实验组与对照组间精子密度差异无显著性（P〉0．05）。结论中频交变磁场对小鼠雄性生殖系统可能存在一定影响。睾丸可能是电磁辐射靶器官之一,对中频磁场（40kHz）极其敏感。而该条件下电磁场对小鼠血液及脑、肝、肾、脾等器官无明显影响。     

不同免疫抑制剂对肾移植患者精子参数的影响

目的:研究不同免疫抑制剂对肾移植患者精子运动功能的影响。方法:20例肾移植患者应用以普乐可复(FK506+霉酚酸酯+泼尼松)、17例应用环孢素(CsA+硫唑嘌呤+泼尼松)为主的免疫抑制治疗方案,15例正常男性为对照组。采用计算机辅助的精子分析系统分别检测精子活率、运动参数(前向运动百分率、直线速度VSL、曲线速度VCL、平均路径速度VAP)和精子形态。结果:3组精子活率[(81.7±5.7)%、(79.4±6.8)%、(83.8±6.0)%]、VCL[(24.1±8.6)%、(23.9±4.4)%、(24.8±4.2)%]和VAP[(19.7±6.6)%、(18.6±2.9)%、(21.0±4.0)%]差异均无显著性(P>0.05);FK506组的精子前向性运动百分率[(46.4±8.1)%]和VSL[(15.4±4.6)%]均显著高于CsA组[(33.3±6.4)%、(10.2±2.4)%],畸形率[(67.8±5.7)%]显著低于CsA组[(80.1±5.6%](P<0.05)。结论:FK506和霉酚酸酯的联合应用,有助于肾移植患者精子运动功能及形态的恢复。     

亚慢性染毒丙烯酰胺对雄性大鼠生殖及睾丸内分泌功能的影响

目的:探讨亚慢性丙烯酰胺染毒对雄性大鼠生殖及睾丸内分泌功能的影响。方法:选择SD雄性成年大鼠40只,随机分成4组,每组10只,灌胃给予丙烯酰胺,剂量分别为0、4、10、18mg/(kg.d),染毒9周。染毒结束后,测量大鼠后肢支撑力,精子存活率、精子畸形率、睾丸匀浆中碱性磷酸酶(ALP)和酸性磷酸酶(ACP)活性、血清和睾丸匀浆中T及E2浓度。建立睾丸Leydig细胞体外原代培养模型,丙烯酰胺体外染毒剂量分为0、0.1、0.75、4、8mmol/L,通过CCK-8法观察Leydig细胞活性。结果:随着染毒剂量的增加,后肢展开距离显著加宽(P<0.01)。精子存活率分别为(76.86±5.46)%、(65.43±5.16)%、(60.86±4.26)%和(46.86±2.73)%,各剂量组与对照组比较显著下降(P<0.01);畸形率分别为(39.00±10.95)%、(35.43±7.54)%、(45.71±13.28)%和(56.71±17.01)%,10、18mg/(kg.d)剂量组明显上升(P<0.05)。ACP活性为(82.93±11.05)、(73.52±8.77)、(77.67±3.04)、(68.56±3.09)U/gprot,呈下降趋势;ALP活性为(0.96±0.15)、(1.07±0.22)、(1.12±0.22)、(0.74±0.10)U/gprot,呈现先上升后下降的趋势。两者的活性在18mg/(kg.d)剂量组与对照组比较差异显著(P<0.05)。血清T浓度分别为(13.44±4.76)、(7.69±3.84)、(5.23±1.42)、(1.36±0.86)ng/ml,睾丸匀浆中T浓度分别为(4.95±1.64)、(3.01±0.76)、(2.44±0.91)、(0.85±0.49)ng/mgprot,两者各剂量组与对照组比较都显著下降(P<0.01)。各剂量组E2水平无明显差异。丙烯酰胺染毒24h后,培养细胞A值分别为0.82±0.06、0.56±0.07、0.44±0.06、0.26±0.03和0.45±0.21,0.1、0.75、4、8mmol/L剂量组Leydig细胞活性受到显著抑制(P<0.01)。结论:亚慢性丙烯酰胺染毒,影响精子正常发育,引起睾丸一些生化酶活性改变;大鼠后肢运动协调性明显受到影响;丙烯酰胺对Leydig细胞有直接损伤作用,影响其内分泌功能。     

Proteoglycan synthesis in bovine articular cartilage explants exposed to different low-frequency low-energy pulsed electromagnetic fields

OBJECTIVE: To investigate the role of pulsed electromagnetic field (PEMF) exposure parameters (exposure length, magnetic field peak amplitude, pulse frequency) in the regulation of proteoglycan (PG) synthesis of bovine articular cartilage explants. METHODS: Bovine articular cartilage explants were exposed to a PEMF (75 Hz; 2 mT) for different time periods: 1, 4, 9, 24 h. Then, cartilage explants were exposed for 24 h to PEMFs of different magnetic field peak amplitudes (0.5, 1, 1.5, 2 mT) and different frequencies (2, 37, 75, 110 Hz). PG synthesis of control and exposed explants was determined by Na2-35SO4 incorporation. RESULTS: PEMF exposure significantly increased PG synthesis ranging from 12% at 4 h to 17% at 24 h of exposure. At all the magnetic field peak amplitude values, a significant PG synthesis increase was measured in PEMF-exposed explants compared to controls, with maximal effect at 1.5 mT. No effect of pulse frequency was observed on PG synthesis stimulation. CONCLUSIONS: The results of this study show the range of exposure length, PEMF amplitude, pulse frequency which can stimulate cartilage PG synthesis, and suggest optimal exposure parameters which may be useful for cartilage repair in in vivo experiments and clinical application.     

Failure of spinal paired associative stimulation to induce neuroplasticity in the human corticospinal tract

Context/Objective

Paired associative stimulation (PAS) involves paired-stimulation pulses at both the head (via transcranial magnetic stimulation) and the periphery (via peripheral nerve stimulation). The purpose of PAS, when applied to the spinal cord, is to induce neuroplasticity and upregulate the corticospinal tract leading to effector muscles. While limited research has suggested that it is possible to produce neuroplasticity through spinal PAS, all such studies have provided stimulation at a fixed frequency of 0.1 or 0.2 Hz.

Design/Interventions

The present study therefore sought to compare the effectiveness of a typical 0.1 Hz paradigm with a 1 Hz paradigm, and a paradigm which provided stimulation in 5 Hz “bursts”. Two inter-stimulus intervals were tested: one which was expected to produce synchronous pre- and post-synaptic activation at the spinal synapse, and one which was not. The peripheral stimulation was applied at the wrist, to induce thumb adduction.

Results

None of the paradigms were able to successfully induce neuroplasticity in a consistent manner.

Conclusion

The high between-subject variability in this study suggests that responses to the spinal PAS treatment may have been highly individual. This serves to highlight a potential limitation of the spinal PAS treatment, which is that its effectiveness may not be universal, but rather dependent on each specific recipient. This may be a challenge faced by spinal PAS should it continue to be tested as a potential novel therapy.     

Evaluation of spermatogenesis and fertility in F1 male rats after in utero and neonatal exposure to extremely low frequency electromagnetic fields

Aim: To determine whether in utero and neonatal exposure to a 60Hz extremely low frequency electromagnetic field (EMF) results in spermatotoxicity and reproductive dysfunction in the F1 offspring of rats. Methods: Age-matched,pregnant Sprague-Dawley rats were exposed continuously (21h/day) to a 60 Hz EMF at field strengths of 0 (sham control), 5, 83.3 or 500 μT from day 6 of gestation through to day 21 of lactation. The experimentally generated magnetic field was monitored continuously (uninterrupted monitoring over the period of the study) throughout the study. Results: No exposure-related changes were found in exposed or sham-exposed animals with respect to the anogenital distance, preputial separation, testis weight, testicular histology, sperm count, daily sperm production,sperm motility, sperm morphology and reproductive capacity of F1 offspring. Conclusion: Exposure of Sprague-Dawley rats to a 60Hz EMF at field strengths of up to 500μT from day 6 of gestation to day 21 of lactation did not produce any detectable alterations in offspring spermatogenesis and fertility.     

Strong static magnetic field stimulates bone formation to a definite orientation in vitro and in vivo.

The induction of bone formation to an intentional orientation is a potentially viable clinical treatment for bone disorders. Among the many chemical and physical factors, a static magnetic field (SMF) of tesla order can regulate the shapes of blood cells and matrix fibers. This study investigated the effects of a strong SMF (8 T) on bone formation in both in vivo and in vitro systems. After 60 h of exposure to the SMF, cultured mouse osteoblastic MC3T3-E1 cells were transformed to rodlike shapes and were orientated in the direction parallel to the magnetic field. Although this strong SMF exposure did not affect cell proliferation, it up-regulated cell differentiation and matrix synthesis as determined by ALP and alizarin red stainings, respectively. The SMF also stimulated ectopic bone formation in and around subcutaneously implanted bone morphogenetic protein (BMP) 2-containing pellets in mice, in which the orientation of bone formation was parallel to the magnetic field. It is concluded that a strong SMF has the potency not only to stimulate bone formation, but also to regulate its orientation in both in vitro and in vivo models. This is the first study to show the regulation of the orientation of adherent cells by a magnetic field. We propose that the combination of a strong SMF and a potent osteogenic agent such as BMP possibly may lead to an effective treatment of bone fractures and defects.     

Sex hormone status in male rats after exposure to 50 Hz, 5 mTesla magnetic field

The question of whether extremely low frequency magnetic fields can affect biological system has attracted attention. The theoretical possibility of such an interaction is often questioned and the site of interaction is unknown. The influence of extremely low frequency magnetic field of 50 Hz, 5 mTesla on sex hormone status was studied. 60 male albino rats were divided into 6 groups and were continuously exposed to 50 Hz, 5 mTesla magnetic field generated by magnetic field chamber for periods of 1, 2 and 4 weeks. For each experimental point, sham treated group was used as a control. Assay of serum testosterone LH, FSH, and prolactin were performed. Serum testosterone showed no significant changes. FSH showed significant increase than sham exposed group after 1 week magnetic field exposure. LH showed significant increase than sham exposed group only after 4 weeks magnetic field exposure, while serum prolactin hormone level showed a significant increase in all magnetic field exposed groups than sham exposed animals. Exposure to 50 Hz, 5 mTesla magnetic field for periods of 1, 2 and 4 weeks has no effect on testosterone level, some changes on FSH and LH serum levels and increase in serum prolactin level.     

Whole-body Vibration at Thoracic Resonance Induces Sustained Pain and Widespread Cervical Neuroinflammation in the Rat

Background

Whole-body vibration (WBV) is associated with back and neck pain in military personnel and civilians. However, the role of vibration frequency and the physiological mechanisms involved in pain symptoms are unknown.

Questions/purposes

This study asked the following questions: (1) What is the resonance frequency of the rat spine for WBV along the spinal axis, and how does frequency of WBV alter the extent of spinal compression/extension? (2) Does a single WBV exposure at resonance induce pain that is sustained? (3) Does WBV at resonance alter the protein kinase C epsilon (PKCε) response in the dorsal root ganglia (DRG)? (4) Does WBV at resonance alter expression of calcitonin gene-related peptide (CGRP) in the spinal dorsal horn? (5) Does WBV at resonance alter the spinal neuroimmune responses that regulate pain?

Methods

Resonance of the rat (410 ± 34 g, n = 9) was measured by imposing WBV at frequencies from 3 to 15 Hz. Separate groups (317 ± 20 g, n = 10/treatment) underwent WBV at resonance (8 Hz) or at a nonresonant frequency (15 Hz). Behavioral sensitivity was assessed throughout to measure pain, and PKCε in the DRG was quantified as well as spinal CGRP, glial activation, and cytokine levels at Day 14.

Results

Accelerometer-based thoracic transmissibility peaks at 8 Hz (1.86 ± 0.19) and 9 Hz (1.95 ± 0.19, mean difference [MD] 0.290 ± 0.266, p < 0.03), whereas the video-based thoracic transmissibility peaks at 8 Hz (1.90 ± 0.27), 9 Hz (2.07 ± 0.20), and 10 Hz (1.80 ± 0.25, MD 0.359 ± 0.284, p < 0.01). WBV at 8 Hz produces more cervical extension (0.745 ± 0.582 mm, MD 0.242 ± 0.214, p < 0.03) and compression (0.870 ± 0.676 mm, MD 0.326 ± 0.261, p < 0.02) than 15 Hz (extension, 0.503 ± 0.279 mm; compression, 0.544 ± 0.400 mm). Pain is longer lasting (through Day 14) and more robust (p < 0.01) after WBV at the resonant frequency (8 Hz) compared with 15 Hz WBV. PKCε in the nociceptors of the DRG increases according to the severity of WBV with greatest increases after 8 Hz WBV (p < 0.03). However, spinal CGRP, cytokines, and glial activation are only evident after painful WBV at resonance.

Conclusions

WBV at resonance produces long-lasting pain and widespread activation of a host of nociceptive and neuroimmune responses as compared with WBV at a nonresonance condition. Based on this work, future investigations into the temporal and regional neuroimmune response to resonant WBV in both genders would be useful.

Clinical Relevance

Although WBV is a major issue affecting the military population, there is little insight about its mechanisms of injury and pain. The neuroimmune responses produced by WBV are similar to other pain states, suggesting that pain from WBV may be mediated by similar mechanisms as other neuropathic pain conditions. This mechanistic insight suggests WBV-induced injury and pain may be tempered by antiinflammatory intervention.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-015-4315-9) contains supplementary material, which is available to authorized users.     

The Influence of Vibration on Muscle Activation and Rate of Force Development during Maximal Isometric Contractions

At present there appears to be a need for research conducted on the effects of vibration on the contractile ability of skeletal muscle tissue. The aim of this study was to address this issue by examining the effects of a superimposed muscle/tendon vibration at 50.42±1.16 Hz (acceleration 13.24 ± 0.18ms^-2: displacement ≈5mm) on muscular activation and maximal isometric contraction. Sixteen participants with a mean age, body mass, and height of 22 ± 4.4 years, 73.2 ± 11.7 kg and 173.1 ± 9.7 cms, respectively, were recruited for this study. Electromyography and accelerometry from the rectus femoris, and maximal isometric force data characteristics were collected from the dominant limb under conditions of vibration, and no-vibration. A superimposed 50 Hz vibration was used during the contraction phase for the maximal isometric leg extension for the condition of vibration. A one-way ANOVA revealed no significant (p > 0.05) differences between the vibration and no-vibration conditions for peak normalized EMG_RMS (84.74% Vs 88.1%) values. An ANOVA revealed significant (p > 0.05) differences between the peak fundamental frequencies of the FFT between the conditions vibration (27.1 ± 12.2 Hz) and no-vibration (9.8 ± 3.5 Hz). Peak isometric force, peak rate of force development, rate of force development at times 0.05, 0.01, 0.1, 0.5 seconds, and rate of force development at 50, 75, and 90% of peak force were not significantly different. The results of this study suggest that the application of vibration stimulation at 50 Hz during the contraction does not contribute to muscle activation, or enhance force production for maximal isometric contractions.

Key Points

• The application of a vibratory stimulation to the human body increases the normal acceleration resulting in an increase in force and a change in performance
• This study was to address this issue by examining the effects of a direct superimposed muscle/tendon vibration at 50 Hz on isometric strength characteristics
• No improvement or change in isometric force or rate of force development
• No changes to peak normalized EMG_RMS values

Key words: Strength, oscillations, isometric, peak, muscle activation     

Proton magnetic resonance spectroscopy in pituitary macroadenomas: preliminary results

OBJECT: The aim of this study was to correlate proton MR (1H-MR) spectroscopy data with histopathological and surgical findings of proliferation and hemorrhage in pituitary macroadenomas. METHODS: Quantitative 1H-MR spectroscopy was performed on a 1.5-T unit in 37 patients with pituitary macroadenomas. A point-resolved spectroscopy sequence (TR 2000 msec, TE 135 msec) with 128 averages and chemical shift selective pulses for water suppression was used. Voxel dimensions were adapted to ensure that the volume of interest was fully located within the lesion and to obtain optimal homogeneity of the magnetic field. In addition, water-unsuppressed spectra (16 averages) were acquired from the same volume of interest for eddy current correction, absolute quantification of metabolite signals, and determination of full width at half maximum of the unsuppressed water peak (FWHM water). Metabolite concentrations of choline-containing compounds (Cho) were computed using the LCModel program and correlated with MIB-1 as a proliferative cell index from a tissue specimen. RESULTS: In 16 patients harboring macroadenomas without hemorrhage, there was a strong positive linear correlation between metabolite concentrations of Cho and the MIB-1 proliferative cell index (R = 0.819, p < 0.001). The metabolite concentrations of Cho ranged from 1.8 to 5.2 mM, and the FWHM water was 4.4-11.7 Hz. Eleven patients had a hemorrhagic adenoma and showed no assignable metabolite concentration of Cho, and the FWHM water was 13.4-24.4 Hz. In 10 patients the size of the lesion was too small (< 20 mm in 2 directions) for the acquisition of MR spectroscopy data. CONCLUSIONS: Quantitative 1H-MR spectroscopy provided important information on the proliferative potential and hemorrhaging of pituitary macroadenomas. These data may be useful for noninvasive structural monitoring of pituitary macroadenomas. Differences in the FWHM water could be explained by iron ions of hemosiderin, which lead to worsened homogeneity of the magnetic field.     

Comparison of the cheese-wiring effects among three sutures used in rotator cuff repair

Purpose:

The goal of this study was to compare the cheese-wiring effects of three sutures with different coefficients of friction.

Materials and Methods:

Sixteen human cadaveric shoulders were dissected to expose the distal supraspinatus and infraspinatus muscle tendons. Three sutures were stitched through the tendons: #2 Orthocord^™ suture (reference #223114, DePuy Mitek, Inc., Raynham, MA), #2 ETHIBOND* EXCEL Suture, and #2 FiberWire^® suture (FiberWire^®, Arthrex, Naples, FL). The sutures were pulled by cyclic axial forces from 10 to 70 N at 1 Hz for 1000 cycles through a MTS machine. The cut-through distance on the tendon was measured with a digital caliper.

Results:

The cut-through distance in the supraspinatus tendons (mean ± standard deviation, n = 12) were 2.9 ± 0.6 mm for #2 Orthocord^™ suture, 3.2 ± 1.2 mm for #2 ETHIBOND* suture, and 4.2 ± 1.7 mm for #2 FiberWire^® suture. The differences were statistically significant analyzing with analysis of variance (P = 0.047) and two-tailed Student''s t-test, which showed significance between Orthocord^™ and FiberWire^® sutures (P = 0.026), but not significant between Orthocord^™ and ETHIBOND* sutures (P = 0.607) or between ETHIBOND* and FiberWire^® sutures (P = 0.103).

Conclusion:

The cheese-wiring effect is less in the Orthocord^™ suture than in the FiberWire^® suture in human cadaveric supraspinatus tendons.

Clinical Relevance:

Identification of sutures that cause high levels of tendon cheese-wiring after rotator cuff repair can lead to better suture selection.