Search results for "shortening"
showing 10 items of 79 documents
Telomerase reverse transcriptase germline mutations and hepatocellular carcinoma in patients with nonalcoholic fatty liver disease
2017
Abstract In an increasing proportion of cases, hepatocellular carcinoma (HCC) develops in patients with nonalcoholic fatty liver disease (NAFLD). Mutations in telomerase reverse transcriptase (hTERT) are associated with familial liver diseases. The aim of this study was to examine telomere length and germline hTERT mutations as associated with NAFLD‐HCC. In 40 patients with NAFLD‐HCC, 45 with NAFLD‐cirrhosis and 64 healthy controls, peripheral blood telomere length was evaluated by qRT‐PCR and hTERT coding regions and intron–exon boundaries sequenced. We further analyzed 78 patients affected by primary liver cancer (NAFLD‐PLC, 76 with HCC). Enrichment of rare coding mutations (allelic frequ…
Longitudinal association of telomere length and obesity indices in an intervention study with a Mediterranean diet: the PREDIMED-NAVARRA trial
2013
Background: Telomeres are nucleoprotein structures that protect the ends of eukaryote chromosomes. Shorter telomere length (TL) is associated with some age-related human disorders, but its relationship with obesity or adiposity parameters remains unclear. Objective: The aim of this study was to assess the relationship between TL and changes in adiposity indices after a 5-year nutritional intervention. Design and subjects: TL was measured by quantitative real-time PCR in 521 subjects (55-80 years, 55% women). Participants were randomly selected from the PREDIMED-NAVARRA centre after they completed a 5-year intervention programme. Anthropometric parameters were directly measured by trained pe…
Effects of Joint Kinetics on Energy Cost during Repeated Vertical Jumping
2019
The present study was designed to investigate the effects of lower limb joint kinetics on energy cost during jumping.Eight male middle and long-distance runners volunteered for the study. The subjects were asked to repeat vertical jumps at a frequency of 2 Hz for 3 min on a force platform in three different surface inclination conditions: Incline (+8°), Level (0°), and Decline (-8°). Sagittal plane kinematics were obtained using a high-speed video camera. Simultaneously, ground reaction forces and EMG of the lower limb muscles were recorded. Energy cost was calculated using steady-state oxygen uptake, respiratory ratio, and vertical distance of the body.In all conditions, energy cost correl…
Behaviour of vastus lateralis muscle-tendon during high intensity SSC exercises in vivo
2003
Aims: The interaction between fascicle and tendinous tissue of human vastus lateralis muscle was investigated during varying intensity stretch–shortening cycle (SSC) jumps performed on a sledge apparatus. Methods: Eight subjects performed single leg squat (SJ) and drop jumps (DJ) from a constant dropping height but to different rebound heights. The fascicle length of the vastus lateralis muscle (VL) was determined from real-time ultrasonography during the movement. Tendon length changes were calculated by subtracting the horizontal part of the fascicle length from the muscle–tendon unit (MTU) length. Simultaneously, kinematic, kinetic and electromyographic data were recorded from leg musc…
Film and digital periapical radiographs for the measurement of apical root shortening
2012
Objectives: The aim of this study was to compare the accuracy and agreement of scanned film and digital periapical radiographs for the measurement of apical root shortening. Study design: Twenty-four film and digital [phosphor plate sensor (PPS)] periapical radiographs were taken using the long-cone paralleling technique for six extracted teeth before and after 1mm of apical root trimming. All teeth were mounted using a typodont and the radiographs were recorded using a film holder and polysiloxane occlusal index for each tooth to ensure standardization during the different radiographic exposures. The film radiographs were scanned and the tooth length measurements for the scanned film and d…
Comparison of force-velocity relationships of vastus lateralis muscle in isokinetic and in stretch-shortening cycle exercises
2003
Aim: This study investigated the force–velocity characteristics of the vastus lateralis (VL) muscle fascicle and muscle–tendon unit (MTU) in isolated lengthening and shortening actions, and during natural movement. Methods: Four subjects performed maximal eccentric and concentric knee extensions (60, 120 and 180° s−1). Unilateral counter movement jumps and drop jumps in the sledge apparatus served as natural movements. Vastus lateralis fascicle lengths were determined from ultrasonography. In vivo patellar tendon forces (PTF) were measured with an optic fibre technique. Patellar tendon force was derived to VL force according to the cross-sectional area of the muscle. Force in the directio…
Estimation of errors in mechanical efficiency
1990
Errors in measurements of mechanical work, net energy expenditure and mechanical efficiency (ME) were calculated, when subjects performed isolated eccentric or concentric muscle actions and combinations of these actions [stretch-shortening cycle (SSC) exercises] with a special sledge apparatus. The relative error of mechanical work was 6.1%. When estimating the error of energy metabolism from oxygen consumption the error would be about 4% (McArdle et al. 1981). The maximum error of ME was the sum of these two values (10.1%). Obviously the error of ME was less than 5%, because 30 muscle actions were averaged and, in addition, the errors of mechanical work and energy expenditure were not in t…
Metformin Restores AMPK Alpha-Mediated Autophagy and Prevents Carfilzomib-Induced Cardiotoxicity In Vivo
2018
Abstract Introduction: Carfilzomib (Cfz) significantly prolongs progression-free survival in relapsed or refractory multiple myeloma patients, as highlighted in the ENDEAVOR trial. However, Cfz has high incidences of cardiotoxicity and heart failure, leading to treatment cessation. Thus, there is an imperative need for preventive therapies. The study aimed to i) establish an in vivo Cfz cardiotoxicity protocol, ii) investigate the molecular mechanism, identify molecular targets and iii) based on initial results, investigate the potential protective effect and mechanism of Metformin (Met). Methods: Male, C57BL/6 mice, were randomized in groups as following: Acute protocol (6 days): Control (…
“Mitotic Slippage” and Extranuclear DNA in Cancer Chemoresistance: A Focus on Telomeres
2020
Mitotic slippage (MS), the incomplete mitosis that results in a doubled genome in interphase, is a typical response of TP53-mutant tumors resistant to genotoxic therapy. These polyploidized cells display premature senescence and sort the damaged DNA into the cytoplasm. In this study, we explored MS in the MDA-MB-231 cell line treated with doxorubicin (DOX). We found selective release into the cytoplasm of telomere fragments enriched in telomerase reverse transcriptase (hTERT), telomere capping protein TRF2, and DNA double-strand breaks marked by γH2AX, in association with ubiquitin-binding protein SQSTM1/p62. This occurs along with the alternative lengthening of telomeres (ALT) and DNA repa…
Stretch-shortening cycle: a powerful model to study normal and fatigued muscle.
2000
Stretch-shortening cycle (SSC) in human skeletal muscle gives unique possibilities to study normal and fatigued muscle function. The in vivo force measurement systems, buckle transducer technique and optic fiber technique, have revealed that, as compared to a pure concentric action, a non-fatiguing SSC exercise demonstrates considerable performance enhancement with increased force at a given shortening velocity. Characteristic to this phenomenon is very low EMG-activity in the concentric phase of the cycle, but a very pronounced contribution of the short-latency stretch-reflex component. This reflex contributes significantly to force generation during the transition (stretch-shortening) pha…