Hepatitis C virus (HCV) is a human pathogen responsible for acute and chronic liver disease, infecting an estimated 130-170 million persons worldwide. An intriguing feature of HCV infection is its ...peculiar relationship with lipids: (1) HCV virions circulate in serum bound to lipoproteins; (2) lipids have been shown to modulate (and, indeed, are essential to) the HCV life cycle; and (3) an occasionally severe accumulation of triglycerides is found in a distinct subgroup of patients in the form of hepatic steatosis. As a result, lipid metabolism is overall altered, conferring an idiosyncratic profile to HCV infection. The scope of this review is to discuss these aspects, focusing on both their molecular mechanisms and their clinical consequences.
HDV is a defective RNA pathogen requiring the simultaneous presence of HBV to complete its life cycle. Two major specific patterns of infection have been described: the coinfection with HDV and HBV ...of a susceptible, anti-HBs-negative individual, or the HDV superinfection of a chronic HBV carrier. Coinfection mostly leads to the eradication of both agents, whereas the majority of patients with HDV superinfection evolve to chronic HDV infection and hepatitis. Chronic HDV infection worsens the preexisting HBV-related liver damage. HDV-associated chronic liver disease (chronic hepatitis D) is characterized by necroinflammation and the relentless deposition of collagen culminating, within a few decades, into the development of cirrhosis and hepatocellular carcinoma.
This review will focus on the impact of steatosis and insulin resistance on the response to antiviral therapy for chronic hepatitis C. Hepatitis C virus (HCV) infection is known to have direct and/or ...indirect effects on lipid and glucose metabolism, leading to, among other disturbances, steatosis and insulin resistance, respectively. Some of these disturbances have a marked HCV genotype distribution. For example, on average, patients with HCV genotype 3 have the highest prevalence and severity of viral fatty liver. On the other hand, the current global spread of the metabolic syndrome represents a formidable cofactor of morbidity in HCV‐related chronic liver disease. Thus, the pathogenesis of steatosis and insulin resistance in patients with chronic hepatitis C may often be dual, i.e. viral and metabolic. This distinction is relevant because the effect (if any) of steatosis or insulin resistance on the response to antiviral agents seems to depend on their pathogenesis. Accumulating data suggest that viral fatty liver may not impact on response to therapy, while metabolic steatosis does. Similarly, viral insulin resistance may not reduce the rate of response to therapy to the same extent that metabolic insulin resistance does. Some implications for patient management are discussed.
Key points
Classic motor unit (MU) recording and analysis methods do not allow the same MUs to be tracked across different experimental sessions, and therefore, there is limited experimental evidence ...on the adjustments in MU properties following training or during the progression of neuromuscular disorders.
We propose a new processing method to track the same MUs across experimental sessions (separated by weeks) by using high‐density surface electromyography.
The application of the proposed method in two experiments showed that individual MUs can be identified reliably in measurements separated by weeks and that changes in properties of the tracked MUs across experimental sessions can be identified with high sensitivity.
These results indicate that the behaviour and properties of the same MUs can be monitored across multiple testing sessions.
The proposed method opens new possibilities in the understanding of adjustments in motor unit properties due to training interventions or the progression of pathologies.
A new method is proposed for tracking individual motor units (MUs) across multiple experimental sessions on different days. The technique is based on a novel decomposition approach for high‐density surface electromyography and was tested with two experimental studies for reliability and sensitivity. Experiment I (reliability): ten participants performed isometric knee extensions at 10, 30, 50 and 70% of their maximum voluntary contraction (MVC) force in three sessions, each separated by 1 week. Experiment II (sensitivity): seven participants performed 2 weeks of endurance training (cycling) and were tested pre–post intervention during isometric knee extensions at 10 and 30% MVC. The reliability (Experiment I) and sensitivity (Experiment II) of the measured MU properties were compared for the MUs tracked across sessions, with respect to all MUs identified in each session. In Experiment I, on average 38.3% and 40.1% of the identified MUs could be tracked across two sessions (1 and 2 weeks apart), for the vastus medialis and vastus lateralis, respectively. Moreover, the properties of the tracked MUs were more reliable across sessions than those of the full set of identified MUs (intra‐class correlation coefficients ranged between 0.63—0.99 and 0.39–0.95, respectively). In Experiment II, ∼40% of the MUs could be tracked before and after the training intervention and training‐induced changes in MU conduction velocity had an effect size of 2.1 (tracked MUs) and 1.5 (group of all identified motor units). These results show the possibility of monitoring MU properties longitudinally to document the effect of interventions or the progression of neuromuscular disorders.
Key points
Classic motor unit (MU) recording and analysis methods do not allow the same MUs to be tracked across different experimental sessions, and therefore, there is limited experimental evidence on the adjustments in MU properties following training or during the progression of neuromuscular disorders.
We propose a new processing method to track the same MUs across experimental sessions (separated by weeks) by using high‐density surface electromyography.
The application of the proposed method in two experiments showed that individual MUs can be identified reliably in measurements separated by weeks and that changes in properties of the tracked MUs across experimental sessions can be identified with high sensitivity.
These results indicate that the behaviour and properties of the same MUs can be monitored across multiple testing sessions.
The proposed method opens new possibilities in the understanding of adjustments in motor unit properties due to training interventions or the progression of pathologies.
Terra Nova, 22, 354–360, 2010
The Raman spectrum of carbonaceous material (CM) from advanced diagenesis (∼200 °C) to low‐grade metamorphism (∼320 °C) is documented in the Helvetic flysch of the ...Glarus Alps (Switzerland). The spectrum is complex, with several defect bands at ∼1200 (D4), ∼1350 (D1), ∼1500 (D3) and ∼1620 (D2) cm−1. We document the evolution of these bands relative to the ‘graphite’ G band with increasing metamorphic grade, and we show that this qualitative evolution may be used as a proxy for temperature in the Glarus Alps. We develop a robust peak‐fitting method and propose quantitative parameters that may be used as proxies for thermal metamorphism in this region. Further work in other geological contexts is needed to assess whether the spectral evolution observed in the Glarus Alps may be generalized and to critically assess the potential for calibrating a general, empirical and quantitative thermometer based on the Raman spectrum of CM in low‐grade rocks.
Aim
Motor units are recruited in an orderly manner according to the size of motor neurones. Moreover, because larger motor neurones innervate fibres with larger diameters than smaller motor neurones, ...motor units should be recruited orderly according to their conduction velocity (MUCV). Because of technical limitations, these relations have been previously tested either indirectly or in small motor unit samples that revealed weak associations between motor unit recruitment threshold (RT) and MUCV. Here, we analyse the relation between MUCV and RT for large samples of motor units.
Methods
Ten healthy volunteers completed a series of isometric ankle dorsiflexions at forces up to 70% of the maximum. Multi‐channel surface electromyographic signals recorded from the tibialis anterior muscle were decomposed into single motor unit action potentials, from which the corresponding motor unit RT, MUCV and action potential amplitude were estimated. Established relations between muscle fibre diameter and CV were used to estimate the fibre size.
Results
Within individual subjects, the distributions of MUCV and fibre diameters were unimodal and did not show distinct populations. MUCV was strongly correlated with RT (mean (SD) R2 = 0.7 (0.09), P < 0.001; 406 motor units), which supported the hypothesis that fibre diameter is associated with RT.
Conclusion
The results provide further evidence for the relations between motor neurone and muscle fibre properties for large samples of motor units. The proposed methodology for motor unit analysis has also the potential to open new perspectives in the study of chronic and acute neuromuscular adaptations to ageing, training and pathology.
Summary
Background
Hepatitis B virus (HBV)/hepatitis C virus (HCV) confection has been rarely studied in nonasian series.
Aim
To compare the characteristics of HBV/HCV coinfected patients to those of ...HBV‐ or HCV‐monoinfected patients in the ANRS CO22 HEPATHER cohort study.
Patients and Methods
Of the 20 936 included patients, 95 had HBV/HCV coinfection (hepatitis B surface antigen, anti‐HCV antibody and HCV RNA positive) and were matched with 375 HBV‐ and 380 HCV‐monoinfected patients on age, gender and time since HBV or HCV diagnosis.
Results
F3‐F4 fibrosis was more frequent in coinfected patients (58%) than in HBV‐ (32%, P < .0001), but similar in HCV‐monoinfected patients (52%, P = .3142). Decompensated cirrhosis was more frequent in coinfected patients (11%) than in HBV‐ (2%, P = .0002) or HCV‐ (4%, P = .0275) monoinfected patients. Past excessive alcohol use was more frequent in coinfected patients (26%) than in HBV (12%, P = .0011), but similar in HCV monoinfected patients (32%, P = .2868). Coinfected patients had a higher proportion with arterial hypertension (42%) than HBV‐ (26%) or HCV‐monoinfected patients (25%) (P < .003). Multivariable analysis confirmed the association between F3‐F4 fibrosis and HCV infection in HBV‐infected patients (OR = 3.84, 95% CI 1.99‐7.43) and the association between decompensated cirrhosis and coinfection in HBV infected (OR = 5.58, 95% CI 1.42‐22.0) or HCV infected patients (OR = 3.02, 95% CI 1.22‐7.44).
Conclusions
HCV coinfection harmfully affects liver fibrosis in HBV patients, while decompensated cirrhosis is increased in coinfected patients compared with HBV‐ or HCV‐monoinfected patients. HCV treatment is as safe and effective in coinfected as monoinfected patients and should be considered following the same rules as HCV monoinfected patients.
Linked ContentThis article is linked to Pol et al and Huang et al papers. To view these articles visit https://doi.org/10.1111/apt.14476 and https://doi.org/10.1111/apt.14445.
The risk of falling in older adults has been related, among other factors, to the reduction of the rate of torque development (RTD) with age. It is well known that both structural/peripheral and ...neural factors can influence the RTD. The purpose of this study was to compare the normalized RTD in young and older participants obtained during a) rapid voluntary tension production and b) neuromuscular electrical stimulation. The tibialis anterior of 19 young subjects (10 males and 9 females; age 21–33 years old) and 19 older participants (10 males and 9 females; age 65–80 years old) was studied. The subjects performed a series of maximal isometric explosive dorsiflexions and underwent trains of supra-maximal electrical stimulations (35 Hz) on the tibialis anterior motor point. Muscle shortening was indirectly measured using a laser (surface mechanomyogram, MMG). Both torque and MMG were normalized to their maximum value. Using a 20 ms sliding window on the normalized torque signal, the normalized maximum RTD was calculated for both voluntary and stimulated contractions. Active stiffness of the muscle- tendon unit was calculated as the area of the normalized torque with respect to the normalized MMG. Normalized maximum RTD was found significantly lower in older adults during voluntary activity (young: 751.9 ± 216.3%/s and old: 513.9 ± 173.9%/s; P < .001), and higher during stimulated contractions (young: 753.1 ± 225.9%/s and old: 890.1 ± 221.3%/s; P = .009). Interestingly, active stiffness was also higher in older adults (young: 3524.6 ± 984.6‰ and old 4144.6 ± 816.6‰; P = .041) and significantly correlated to the normalized maximum RTD during stimulated contractions. This dichotomy suggests that modifications in the structural/peripheral muscle properties are not sufficient to counteract the age-related decrease in neural drive to the muscle during voluntary isometric contractions in aged participants.
•Voluntary and stimulated contraction torque rate transients in young and old adults•Muscle stimulation: normalized rate of torque development larger in old than young•Laser mechanomyogram for active stiffness calculation•Positive correlation between active stiffness and normalized torque rate transient•Higher active stiffness in old adult no compensate for muscle neural drive worsening
The article aims to elaborate on European policy choices for the prevention of SARS‑CoV‑2 contagion, with a close focus on the rules and regulations enacted in Italy so far. European states have ...ruled out generalized vaccination mandates but have so far preferred to exert a form of "moral suasion", through the introduction of a digital certificate which can only be granted to those who are vaccinated, cured of COVID-19 or tested negative through an antigen test in the previous 48 hours. Italy has applied this tool, dubbed "Green Pass", very rigorously: many daily activities, including going to work, are only allowed for those who have the certificate. A one-year Green Pass is issued after vaccination, although data show that vaccine protection may subside gradually over about six months; the cost of the antigen tests every 48 hours is to be borne by the patient. Testing the unvaccinated is essential to contain the spread of the infection, but it would have been more logical to mandate that all the unvaccinated undergo regular testing (for example every ten days), instead of imposing a test every 48 hours only to be allowed to engage in some activities. The authors stress that in order to minimize the risk of future possible pandemics, prevention strategies are needed, and poor countries need to be enabled to vaccinate their populations in order to prevent new variants from developing. The pledges made by world leaders in that regard during the recent G20 summit must therefore be honored, for the sake of global health that never in our lifetime has been so threatened.
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