Relationship between shear elastic modulus and passive force of the human rectus femoris at multiple sites: a Thiel soft-embalmed cadaver study.

PURPOSE: Estimation of muscle passive force from elasticity using shear wave elastography (SWE) has been reported. However, the relationship between the elasticity and passive force of human muscles has not been elucidated. This study investigated the elastic modulus-passive force relationship in human skeletal muscles at multiple sites. METHODS: Four rectus femoris (RF) muscles were dissected from a human Thiel-embalmed cadaver. Calibration weights (0-600 g in 60-g increments) were applied to the distal tendon via a pulley system, and the shear elastic modulus as an index of elasticity was measured using SWE. The shear elastic modulus of the RF was measured at the proximal, central, and distal portions. RESULTS: The results demonstrated that the relationships between the elasticity in the longitudinal direction of the muscle and the passive force were nearly linear for all tested sites, with coefficients of determination ranging from 0.813 to 0.993. CONCLUSION: Shear wave elastography may be used as an indirect method to measure the changing passive force at any site within human muscles.

Activated forms of astrocytes with higher GLT-1 expression are associated with cognitive normal subjects with Alzheimer pathology in human brain.

Although the cognitive impairment in Alzheimer's disease (AD) is believed to be caused by amyloid-ß (Aß) plaques and neurofibrillary tangles (NFTs), several postmortem studies have reported cognitive normal subjects with AD brain pathology. As the mechanism underlying these discrepancies has not been clarified, we focused the neuroprotective role of astrocytes. After examining 47 donated brains, we classified brains into 3 groups, no AD pathology with no dementia (N-N), AD pathology with no dementia (AD-N), and AD pathology with dementia (AD-D), which represented 41%, 21%, and 38% of brains, respectively. No differences were found in the accumulation of Aß plaques or NFTs in the entorhinal cortex (EC) between AD-N and AD-D. Number of neurons and synaptic density were increased in AD-N compared to those in AD-D. The astrocytes in AD-N possessed longer or thicker processes, while those in AD-D possessed shorter or thinner processes in layer I/II of the EC. Astrocytes in all layers of the EC in AD-N showed enhanced GLT-1 expression in comparison to those in AD-D. Therefore these activated forms of astrocytes with increased GLT-1 expression may exert beneficial roles in preserving cognitive function, even in the presence of Aß and NFTs.

The anterolateral ligament in a Japanese population: Study on prevalence and morphology.

BACKGROUND: The anterolateral ligament of the knee (ALL) has been attracting research attention as the ligament related to the Segond fracture. In this study, we investigated the prevalence and morphological variation of the ALL and developed a classification for the ALL in Japanese people. METHODS: A total of 94 knees of 54 room cadavers of Japanese people were examined (24 male, 30 female; age range 70-103 years; average age: 85.6 years). Knees with damaged ligaments, such as ACL rupture, and with bony abnormalities were excluded. The ALL-like structure was classified based on orientation and shape of the structures. RESULTS: The fibrous structure independent from the knee joint capsule in the anterolateral part of the knee was present in 35 knees out of 94 knees (37.2%). This structure was classified into two types, based on thickness: type I is for the strong ligamentous structures of more than 1 mm in thickness; and type II is for weak aponeurotic structures of equal or less than 1 mm thickness. Here we regard the anterolateral ligament (ALL) as the type I and the type II is termed anterolateral ligamentous tissue (ALLT). Type I was seen in 19 of 35 knees (54.3%), and type II was seen in 16 of 35 knees (45.7%). CONCLUSIONS: This study described the fibrous structure of the anterolateral portion of the knee, and classified the ligamentous structure into type I (ALL) and thin aponeurotic type II (ALLT). The prevalence of the ALL in Japanese people was approximately 20% and was significantly lower than in previous studies, which were reported values from 50% to 100%.