Browsing by Subject "Atrophy"
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- PublicationOpen AccessMatrix metalloproteinase imbalance in muscle disuse atrophy(Murcia : F. Hernández, 2005) Giannelli, G.; De Marzo, A.; Marinosci, F.; Antonaci, S.Muscle atrophy commonly occurs as a consequence of prolonged muscle inactivity, as observed after cast immobilization, bed rest or space flights. The molecular mechanisms responsible for muscle atrophy are still unknown, but a role has been proposed for altered permeability of the sarcolemma and of the surrounding connective tissue. Matrix metalloproteinases (MMPs) are a family of enzymes with proteolytic activity toward a number of extracellular matrix (ECM) components; they are inhibited by tissue inhibitors of MMPs (TIMPs). In a rat tail-suspension experimental model, we show that after fourteen days of non-weight bearing there is increased expression of MMP-2 in the atrophic soleus and gastrocnemius and decreased expression of TIMP-2. In the same experimental model the expression of Collagen I and Collagen IV, two main ECM components present in the muscles, was reduced and unevenly distributed in unloaded animals. The difference was more evident in the soleus than in the gastrocnemius muscle. This suggests that muscle disuse induces a proteolytic imbalance, which could be responsible for the breakdown of basal lamina structures such as Collagen I and Collagen IV, and that this leads to an altered permeability with consequent atrophy. In conclusion, an MMP-2/TIMP-2 imbalance could have a role in the mechanism underlying muscle disuse atrophy; more studies are needed to expand our molecular knowledge on this issue and to explore the possibility of targeting the proteolytic imbalance with MMP inhibitors.
- PublicationOpen AccessMuscular hypertrophy and atrophy in normal rats provoked by the administration of normal and denervated muscle extracts(Universidad de Murcia. Departamento de Biología Celular e Histología, 2016) Agüera, Eduardo; Castilla, Salvador; Luque, Evelio; Jimena, Ignacio; Leiva Cepas, Fernando; Ruz Caracuel, Ignacio; Peña, JoséThis study was conducted to determine the effects of extracts obtained from both normal and denervated muscles on different muscle types. Wistar rats were used and were divided into a control group and four experimental groups. Each experimental group was treated intraperitoneally during 10 consecutive days with a different extract. These extracts were obtained from normal soleus muscle, denervated soleus, normal extensor digitorum longus, and denervated extensor digitorum longus. Following treatment, the soleus and extensor digitorum longus muscles were obtained for study under optic and transmission electron microscope; morphometric parameters and myogenic responses were also analyzed. The results demonstrated that the treatment with normal soleus muscle and denervated soleus muscle extracts provoked hypertrophy and increased myogenic activity. In contrast, treatment with extracts from the normal and denervated EDL had a different effect depending on the muscle analyzed. In the soleus muscle it provoked hypertrophy of type I fibers and increased myogenic activity, while in the extensor digitorum longus atrophy of the type II fibers was observed without changes in myogenic activity. This suggests that the muscular responses of atrophy and hypertrophy may depend on different factors related to the muscle type which could be related to innervation.
- PublicationOpen AccessPanoramic ultrasound requires a trained operator and specific evaluation sites to maximize its sensitivity: a comprehensive analysis of the measurement errors(Elsevier, 2022-02-08) Hernández Belmonte, Alejandro; Martínez Cava, Alejandro; García Pallarés, Jesús; Actividad Física y DeporteThis study aimed to examine the validity and repeatability of panoramic ultrasound to evaluate the anatomical cross-sectional area (ACSA) of quadriceps femoris muscles. Specifically, we aimed to quantify the errors generated during the image acquisition and analysis (repeatability), as well as when comparing with magnetic resonance imaging (MRI) (validity). Moreover, we analyzed the influence of the operator's experience and the region of the thigh, on these errors. Both thighs of 16 subjects were included. The validity and repeatability study quantified the errors made by two operators (trained and novice) when measuring ACSA of vastus lateralis (VL), vastus medialis-intermedius (VMVI), and rectus femoris (RF), in six thigh regions (from 20 to 70%). Two ACSA images were acquired 5 min apart to examine acquisition errors, whereas acquisition #1 was analyzed twice to quantify analysis errors. Thereafter, ACSA of acquisition #1 was compared with that measured by MRI. Statistics included the standard error of measurement (SEM) expressed in absolute (cm2) and relative terms (%) as a coefficient of variation (CV). Measurement errors were lower for the trained operator than for the novice: Acquisition (SEM = 0.05 – 0.78 vs. 0.25 – 1.42 cm2), analysis (SEM = 0.13 – 1.93 vs. 0.30 – 3.05 cm2) and compared-with-MRI (SEM = 0.13 – 1.93 vs. 0.30 – 3.05 cm2). Regions with the lowest errors were those located at the middle of the thigh (40–50%), although slight between-muscle differences were found: VMVI (30–40%), VL (40–50%), RF (50–60%). These findings suggest that the accurate implementation of panoramic ultrasound to measure ACSA of quadriceps femoris muscles requires a trained operator and specific evaluation sites.
- PublicationEmbargoPectoralis cross-sectional area can be accurately measured using panoramic ultrasound: a validity and repeatability study(2021-11-30) Hernández Belmonte, Alejandro; Martínez Cava, Alejandro; García Pallarés, Jesús; Actividad Física y DeporteThe objective of the current study was to examine the validity and repeatability of panoramic ultrasound in evaluating the anatomical cross-sectional area (ACSA) of the pectoralis major. Specifically, we aimed to quantify the measurement errors generated during the image acquisition and analysis (repeatability), as well as when comparing with magnetic resonance imaging (MRI) (validity). Moreover, we aimed to analyze the influence of the operator’s experience on these measurement errors. Both sides of the chest of 16 participants (n = 32) were included. Errors made by two operators (trained and novice) when measuring pectoralis major ACSA (50% of sternum areola mammae distance) were examined. Acquisition errors included the comparison of two images acquired 5 min apart. Acquisition 1 was analyzed twice to quantify analysis errors. Thereafter, acquisition 1 was compared with MRI. Statistics include the standard error of measurement (SEM), expressed in absolute (cm2) and relative (%) terms as a coefficient of variation (CV), and the calculation of systematic bias. Errors made by the trained operator were lower than those made by the novice, especially during the image acquisition (SEM = 0.25 vs. 0.66 cm2, CV = 1.06 vs. 2.98%) and when compared with MRI (SEM = 0.27 vs. 1.90 cm2, CV = 1.13 vs. 8.16%). Furthermore, although both operators underestimated the ACSA, magnitude and variability [SD] of these errors were lower for the trained operator (bias = 0.19 [0.34] cm2) than for the novice (bias = 1.97 [2.59] cm2). Panoramic ultrasound is a valid and repeatable technique for measuring pectoralis major ACSA, especially when implemented by a trained operator.
- PublicationOpen AccessSonoelastography for the Assessment of Muscle Changes in Amyotrophic Lateral Sclerosis: Results of a Pilot Study(Elsevier, 2018) Martínez Payá, Jacinto Javier; Baño Aledo, María Elena del; Ríos Díaz, José; Fornés Ferrer, Victoria; Vázquez Costa, Juan F.; FisioterapiaThe purpose of this study was to assess the sonoelastographic features of four different muscles in patients with amyotrophic lateral sclerosis compared with healthy controls and to evaluate the relationship of these features to muscle strength and other ultrasonographic variables. Fourteen patients with amyotrophic lateral sclerosis and 20 controls were examined using strain sonoelastography scanning. The RGB channel fraction ratio was analyzed with ImageJ software (Version 1.48). Two main sonoelastographic patterns could be distinguished in the controls: a clear predominance of the blue channel (hard areas) and a more heterogeneous pattern with predominance of the green channel (intermediate stiffness). These patterns were also observed in patients, although a higher green channel score was observed in mildly impaired muscles, whereas a higher blue channel score was observed in the most severely impaired muscle. Sonoelastography may be a good complementary biomarker in the detection and monitoring of muscle changes in amyotrophic lateral sclerosis.
- PublicationEmbargoThe 2-point method: A quick, accurate, and repeatable approach to estimate ultrasoundderived quadriceps femoris cross-sectional area(Human Kinetics, 2022-07-18) Hernández Belmonte, Alejandro; Martínez Cava, Alejandro; García Pallarés, Jesús; Actividad Física y DeportePurpose: To analyze the feasibility of the 2-point method for estimating ultrasound-derived quadriceps femoris cross-sectional area (QUADACSA). First, (1) the agreement between QUADACSA measured by panoramic ultrasound and magnetic resonance imaging (MRI) was studied, and thereafter, we examined 2 approaches of the 2-point method in terms of (2) estimation errors and (3) test–retest repeatability. Methods: Both thighs of 16 young men were analyzed. Ultrasound-QUADACSA versus MRI-QUADACSA comparison was conducted at 6 thigh lengths (20%–70% of the thigh length). Thereafter, ultrasound-QUADACSA corresponding to 30% and 60% (2-point30%–60%) or 20% and 70% (2-point20%–70%) were used to estimate QUADACSA of the remaining regions. Estimated QUADACSA resulting from both 2-point approaches was compared with the measured one. Finally, the test–retest repeatability was examined by comparing the errors generated on 2 separate estimations. Statistics included the standard error of measurement (SEM) expressed in absolute (in square centimeters) and relative terms (in percentage) as a coefficient of variation (CV), as well as the intraclass correlation cofficient (ICC) and bias. Results: An excellent agreement (ICC ≥ 0.980) and reduced errors (SEM ≤ 2.43 cm2) resulted from the ultrasound-QUADACSA versus MRI-QUADACSA comparison. Although estimation errors found were reduced (CV ≤ 7.50%), they proved to be lower and less biased for the 2-point30%–60%, especially at the central regions (SEM ≤ 2.01 cm2; bias ≤ 0.89 cm2). Similarly, repeatability analysis revealed lower test–retest errors for the 2-point30%–60% (CV ≤ 1.9%) than for the 2-point20%–70% (CV ≤ 4.6%). Conclusion: The 2-point method, especially that implemented using the 30% and 60% regions, represents an accurate and repeatable strategy to evaluate QUADACSA.
- PublicationOpen AccessThe pathology of the atrophylhypertrophy complex (AHC) of the liver. A light microscopic and immunohistochemical study(Murcia : F. Hernández, 1994) Lory, J.; Schweizer, W.; Blumgart, L.H.; Zimmermann, AstridThe term, atrophylhypertrophy complex (AHC) of the liver, denotes a distinct combination of hepatic atrophy and hypertrophy occurring in situations of significant impairment of bile flow andlor portal or hepatic venous blood flow. In the lobes or segments concerned atrophy ensues, whereas areas not or less involved develop compensatory hypertrophy, resulting in a characteristic gross deformity of the organ and, in some instances, in rotation of the liver around a virtual hilar axis. As recognition and early detection of AHC have a strong implication on the treatment of several hepatobiliary diseases, adequate combined clinical, radiological and histopathological strategies have to be used in order to arrive at a correct diagnosis. The present investigation was designed to analyze the morphology of AHC in detail and to define lesion patterns having the highest predictive value. For atrophy, the following features were highly characteristic: 1) Advanced septal fibrosis with or without nodular change of parenchyma; 2) Biliary piecemeal necrosis with formation of vascular structures; 3) Ductular proliferations, frequently extending into septa and involving the parenchyma; 4) Capillarization of sinusoids with type IV collagen deposition in Disse's space; 5) Factor VIII-associated antigen expression by sinusoidal endothelia; 6) a seemingly paradoxical increase of proliferative activity of hepatocytes as based on PCNA staining. The severity of lesions in atrophy was related to the type of underlying disease, in that the changes were clearly more expressed in situations of longstanding obstruction due to benign disease. Using a set of well-defined morphological parameters, atrophy can be reproducibly distinguished from hypertrophy in biopsy material from AHC.