Store-operated calcium entry relies on the formation of a specialized compartment derived from the endoplasmic reticulum (ER) and closely apposed to the plasma membrane. In this study, detailed ultrastructural analysis revealed the existence of three distinct structures derived from conventional ER: precortical ER, cortical ER, and thin cortical ER. Precortical subdomains of the ER enriched in STIM1 can form without contacting the plasma membrane. Upon ER calcium depletion, these subdomains are translocated to the plasma membrane to form cortical ER, which is still connected to the conventional ER. Thin cortical ER, depleted of BiP and deprived of attached ribosomes, may represent a specialized region dedicated to calcium regulation and not engaged in protein translocation and folding. These observations form the basis for future structure-function analysis of cortical ER.calcium ͉ store-operated calcium entry

A Pilot Studyonoelastography is now routinely used in medical sonography since Ophir et al 1 first described the principles of strain imaging in 1991. The technique can assess the elastic properties of tissues, and static elastography has found clinical application in diagnosing lesions of the breast, 2 thyroid, 3 lymph nodes, 4 and prostate gland. 5 The basic principle of sonoelastography is to produce displacement within the tissue by physical compression. By comparing the images taken before and after the application of compression, sonoelastography can show different degrees of displacement. 1 However, the stiffness of the tissue can only be obtained by comparing it with surrounding normal tissues. The degree of the compression applied by the operator may alter the results of sonoelastography. -Mei Chen, MD, PhD, Li-Gang Cui, MD, PhD, Ping He, MD, PhD, Wei-Wei Shen, MD, MS, Ya-Jun Qian, MD, MS, Jin-Rui Wang, MD, BS Received June 4, 2012, Xiang ORIGINAL RESEARCHObjectives-The purpose of this study was to investigate the feasibility of using quantitative shear wave elastography for assessing the functional integrity of the Achilles tendon and to summarize the changes in elasticity of ruptured Achilles tendons in comparison with normal controls.Methods-Thirty-six normal and 14 ruptured Achilles tendons were examined with shear wave elastography coupled with a linear array transducer (4-15 MHz). The elasticity value of each Achilles tendon in a longitudinal view was measured.Results-The mean elasticity value ± SD for the normal Achilles tendons was 291.91 ± 4.38 kPa (note that there are saturated measurement phenomena for the normal Achilles tendon, so the actual value will be >300 kPa), whereas the ruptured Achilles tendons had an elasticity value of 56.48 ± 68.59 kPa. A statistically significant difference was found in relation to the findings in healthy volunteers (P = .006).Conclusions-Our results suggest that shear wave elastography is a valuable tool that can provide complementary biomechanical information for evaluating the function of the Achilles tendon.

Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time-varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4-month-old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin-treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia-tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2 IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor-beta 1 (TGF-beta1), and interleukin-6 (IL-6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF-beta1 concentration in the PEMF group increased significantly after 8 weeks. The IL-6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL-6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF-beta1 secretion and inhibiting IL-6 expression.

Caveolae are small invaginated pits that function as dynamic mechanosensors to buffer tension variations at the plasma membrane. Here we show that under mechanical stress, the EHD2 ATPase is rapidly released from caveolae, SUMOylated, and translocated to the nucleus, where it regulates the transcription of several genes including those coding for caveolae constituents. We also found that EHD2 is required to maintain the caveolae reservoir at the plasma membrane during the variations of membrane tension induced by mechanical stress. Metal-replica electron microscopy of breast cancer cells lacking EHD2 revealed a complete absence of caveolae and a lack of gene regulation under mechanical stress. Expressing EHD2 was sufficient to restore both functions in these cells. Our findings therefore define EHD2 as a central player in mechanotransduction connecting the disassembly of the caveolae reservoir with the regulation of gene transcription under mechanical stress.