Mechanical influence of the extrafusal muscle on the static behaviour of deefferented primary muscle spindle endings in cat

Summary In 16 anesthetized cats 24 afferents of deefferented primary muscle spindle endings from the extensor digitorum longus muscle (EDL) were functionally isolated and their sensitivity to static stretches was tested. Each spindle was carefully located within the EDL using direct focal stimulation. Muscle spindle endings with poor static length sensitivity of stretch were always found in the most peripheral parts of the muscle fibre bundles, near to the aponeurotic and tendineous insertions. Endings having good static sensitivity to stretch were exclusively found in more central portions of the muscle fibre bundles. Using a photographic method, the alterations in the distance between designated points on the muscle surface ware measured during maintained muscle stretch. Only medial portions were markedly extended, whereas little or no increases in length occurred in peripheral parts of the muscle fibre bundles.Quantitatively, a direct relationship was found between the lengthening of those muscle portions, in which the muscle spindles were localized, and the receptors' sensitivity to maintained stretch.Preliminary reports of some of the results were given at the 1. Wissenschaftliche Tagung der Deutschen Gesellschaft für medizinische Physik (Rieboldet al., 1970; Robrechtet al., 1970) and at the Muscle-Spindle Symposium of the Anatomical Society of Great Britain and Ireland, April 4–6, 1974, at the University of Durham (Henatschet al., 1974). The results were presented in more detail in Meyer-Lohmann's Habilitationsschrift (1972).Supported by a grant from the Deutsche Forschungsgemeinschaft (Schwer-punktprogramm Rezeptorphysiologie).     

Intense Pulsed Light Treatment of 1,000 Consecutive Patients with Facial Vascular Marks

Background: Facial teleangectasias or vascular marks often represent a very cosmetically detracting problem for the affected patient, who tries to cover the lesions by camouflage strategies. This study describes the response of these vascular lesions after an intense pulsed light source was used on 1,000 consecutive patients. Methods: Between October 1998 and April 2005, 1,000 consecutive patients with various skin types (Fitzpatrick I to IV) were treated with Photoderm VL. The average age of the patients was 47.1 years. These patients were subjected to a mean of 2.16 treatments (range, 1–9), then followed up 48 h, 72 h, 1 week, 3 weeks, and 1 month after each treatment. All the patients were followed up 2 months after the last treatment, and the percentage of clearance was assessed by comparison of pre- and posttreatment photographs. The patients also answered a questionnaire in which they expressed personal satisfaction. The final physicians-nurse evaluation also was recorded on the same form. Results: Most of the patients (89.70%) experienced a clearance of 75% to 100%. The results appear to be correlated with operator experience, but not with lesion size, age, or skin type. Minimal adverse side effects occurred for 14.6% of the patients, but only for 6.76% of the treatments. Conclusion: The intense pulsed light source Photoderm VL can be considered a fast, safe, and effective treatment for facial teleangectasias or vascular marks.     

The reduction of excitability of the γ-loop by 1,3-dimethyl-5-aminoadamantane (DMAA)

Summary The -loop of pretibial flexor muscles was investigated before and after i.v. injection of 10 mg/kg DMAA in precollicular and prenigral decerebrate cats. DMMA reduces significantly the reflex discharge rate of Ia muscle spindle afferents, a result which might be important in regard of a hyperactive -motor system.Supported by the Deutsche Forschungsgemeinschaft, SFB 33.     

Relume光子色素再生仪治疗妊娠纹的临床应用观察

目的 观察Relume光子色素再生仪治疗妊娠纹的临床效果。方法 用Relume光子色素再生仪的紫外线B波(UVB)，治疗腹部妊娠纹20例，根据皮肤类型选择特定波长，不同能量密度的紫外光子点击腹部妊娠纹，1周治疗1次，共治疗6次。结果 除3例病人未完成治疗，随访17例4个月，100％患者妊娠纹表面出现增色效果，增色效果非常满意的为29．4％(5例)，增色效果满意的为70．6％(12例)。结论 Relume光子色素再生仪是治疗腹部妊娠纹安全有效的手段。     

The influence of perturbation duration and velocity on the long-latency response to stretch in the biceps muscle

Different neural pathways are proposed to mediate the long-latency stretch reflex response (M2) in muscles spanning distal and proximal joints of the upper limb. The M2 at the wrist joint is present only if the duration of the perturbation exceeds a critical time. Lee and Tatton put forward a converging input hypothesis, requiring an interaction of excitatory volleys at the spinal cord, to account for this feature. The goal of the present study was to examine the influence of the duration of perturbation on M2 responses elicited in a muscle spanning the elbow joint. Reflex responses were induced in the biceps brachii muscle by applying ramp-and-hold position displacements to the elbow. It was found that the M2 was strongly dependent on the duration of the perturbation. On average, responses were not elicited following perturbations of less than 35±5 ms. Using a novel double-movement paradigm, we were unable to provide support for the converging input hypothesis. The effect of the duration of perturbation on the M2 may account for the conflicting characteristics of the M2 that have been provided by previous studies applying mechanical or electrical perturbations of varying time durations.     

应用磁共振DWI单指数、双指数和拉伸指数模型参数评估慢性乙型肝炎患者肝纤维化程度效能研究*

目的 探讨应用磁共振DWI单指数、双指数和拉伸指数模型参数评估慢性乙型肝炎（CHB）患者肝纤维化程度的临床价值。方法 2014年2月~2017年9月我院收治的CHB患者77例,选择同时期20例健康人作为对照,对CHB患者行肝活检,两组受试者接受磁共振检查,测量单指数模型、双指数模型和拉伸指数模型参数,其中ADCst为表面扩散系数,Dt为真实扩散系数,Dp为假性扩散系数,f为灌注相关体积分数,DDC为扩散分布指数,α为水分子扩散异质性指数。结果 CHB单指数模型的ADCst、双指数模型的Dt、拉伸指数模型的f和DDC分别为（0.899±0.080）×10^-3 mm²/s、（0.591±0.092）×10^-3 mm²/s、（32.374±7.472）×10^-3 mm²/s和（1.103±0.257）×10^-3 mm²/s,显著低于健康人【（0.986±0.095）×10^-3 mm²/s、（0.704±0.073）×10^-3 mm²/s、（39.686±5.871）×10^-3 mm²/s和（1.394±0.243）×10^-3 mm²/s,P<0.05】;在25例无显著肝纤维化、29例显著肝纤维化和23例肝硬化患者中,ADCst、Dt、f和DDC显著差异（P<0.05）;ADCst、Dt、f和DDC诊断肝纤维化的ROC曲线下面积分别为0.841、0.934、0.770和0.926。结论 应用磁共振双指数模型和拉伸指数模型诊断CHB患者肝纤维化比应用单指数模型具有更好的诊断效果,值得进一步研究验证。     

The sarcomeric Z-disc: a nodal point in signalling and disease

The perception of the Z-disc in striated muscle has undergone significant changes in the past decade. Traditionally, the Z-disc has been viewed as a passive constituent of the sarcomere, which is important only for the cross-linking of thin filaments and transmission of force generated by the myofilaments. The recent discovery of multiple novel molecular components, however, has shed light on an emerging role for the Z-disc in signal transduction in both cardiac and skeletal muscles. Strikingly, mutations in several Z-disc proteins have been shown to cause cardiomyopathies and/or muscular dystrophies. In addition, the elusive cardiac stretch receptor appears to localize to the Z-disc. Various signalling molecules have been shown to interact with Z-disc proteins, several of which shuttle between the Z-disc and other cellular compartments such as the nucleus, underlining the dynamic nature of Z-disc-dependent signalling. In this review, we provide a systematic view on the currently known Z-disc components and the functional significance of the Z-disc as an interface between biomechanical sensing and signalling in cardiac and skeletal muscle functions and diseases.     

The effect of 30 minutes of passive stretch of the rat soleus muscle on the myogenic differentiation, myostatin, and atrogin-1 gene expressions

The effect of 30 minutes of passive stretch of the rat soleus muscle on the myogenic differentiation, myostatin, and atrogin-1 gene expressions. OBJECTIVE: To evaluate the effect of passive stretch, applied for 30 minutes to the rat soleus muscle, on the myogenic differentiation (myoD), myostatin, and atrogin-1 gene expressions. DESIGN: Case-controlled study. SETTING: University laboratory. ANIMALS: Fifty 12-week-old male Wistar rats. INTERVENTIONS: Six groups of animals were given a single stretch bout and were evaluated immediately and 8, 24, 48, 72, and 168 hours later. Another 3 groups were evaluated immediately after 2, 3, and 7 stretches. An intact control group was also analyzed. MAIN OUTCOME MEASURES: The messenger ribonucleic acid (mRNA) levels of myoD, myostatin, and atrogin-1 were assessed by real-time polymerase chain reaction. RESULTS: Twenty-four hours after a single session of stretch only, the myoD mRNA levels had increased compared with the control group, whereas an increase in the atrogin-1 expression was observed after 2, 3, and 7 stretches. CONCLUSIONS: A single session of passive stretch increased the myoD gene expression, a factor related to muscle growth. Interestingly, daily stretches increased the atrogin-1 gene expression, a gene primarily associated with muscle atrophy. The results indicated that gene expression was responsive to the number of stretch sessions.     

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.     

膨胀缺血预适应离体大鼠心脏所致心律失常及其机制

目的　研究缺血预适应 (ischemicpreconditioning ,IPC)条件下膨胀离体大鼠心脏所诱发的心律失常及链霉素对其影响。方法　采用Langendorff方法灌流离体大鼠心脏。将可充灌液体的乳胶球囊通过左心房及二尖瓣置于左心室 ,通过向乳胶球囊注射液体对左室进行膨胀 ,记录膨胀前和膨胀过程中左室心电图和左室压力 ,冠脉流量和心率 ;并计算对照组和各实验组由膨胀诱发心律失常的发生率和持续时间。结果　通过乳胶球囊膨胀离体大鼠左室可诱发对照组和IPC组发生心律失常 ;在左室舒张末压增加相同的情况下 ,IPC组较对照组室性早搏和室性心动过速发生率均降低 ,持续时间缩短 ;链霉素干预后 ,IPC心脏心律失常发生情况明显改善。结论　对离体大鼠心室进行膨胀可诱发心律失常 ;IPC条件下大鼠心脏对牵张的耐受性增强 ,链霉素对膨胀IPC离体大鼠心脏所致心律失常具有抑制作用。