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Capitanio M.,University of Florence | Canepari M.,University of Pavia | Maffei M.,University of Pavia | Beneventi D.,University of Florence | And 6 more authors.
Nature Methods | Year: 2012

We describe a dual-trap force-clamp configuration that applies constant loads between a binding protein and an intermittently interacting biological polymer. The method has a measurement delay of only ∼10 μs, allows detection of interactions as brief as ∼100 μs and probes sub-nanometer conformational changes with a time resolution of tens of microseconds. We tested our method on molecular motors and DNA-binding proteins. We could apply constant loads to a single motor domain of myosin before its working stroke was initiated (0.2-1 ms), thus directly measuring its load dependence. We found that, depending on the applied load, myosin weakly interacted (<1 ms) with actin without production of movement, fully developed its working stroke or prematurely detached (<5 ms), thus reducing the working stroke size with load. Our technique extends single-molecule force-clamp spectroscopy and opens new avenues for investigating the effects of forces on biological processes. © 2012 Nature America, Inc. All rights reserved.


Nardone A.,University of Piemonte Orientale | Nardone A.,Scientific Institute of Veruno | Schieppati M.,University of Pavia | Schieppati M.,Scientific Institute of Pavia
European Journal of Physical and Rehabilitation Medicine | Year: 2010

This review addresses the issue whether instrumental evaluations of balance may be helpful in orienting the clinical decision regarding balance rehabilitation. The aptitude of instrumental assessment of balance in supporting decision making in patients with balance disorders connected with ageing and with neurological diseases is considered. Among instrumental evaluations, recording of body sway during quiet stance and dynamic conditions are described, together with manoeuvres for recording postural reactions to predictable or unpredictable postural perturbations. The posturography patterns encountered in elderly subjects and patients affected by Parkinson's disease, spasticity, peripheral neuropathy, cerebellar diseases, vestibular deficit and neck disorders are presented and discussed. Findings from instrumental assessments of balance are helpful in understanding the pathophysiology of balance disorders, in screening for balance disorders, and in evaluating the natural progression of the disease or the response to therapy, be it physical or pharmacological. Conversely, as far as the prediction of the risk of falling in one individual patient is concerned, the various posturography tests do not produce consistent results.


Nava S.,University of Bologna | Esquinas A.,Hospital Morales Meseguer | Scala R.,Respiratory Ward and Respiratory Intermediate Care Unit | Groff P.,Madonna del Soccorso Hospital | And 7 more authors.
The Lancet Oncology | Year: 2013

Background: Despite best-possible medical management, many patients with end-stage cancer experience breathlessness, especially towards the end of their lives. We assessed the acceptability and effectiveness of non-invasive mechanical ventilation (NIV) versus oxygen therapy in decreasing dyspnoea and the amount of opiates needed. Methods: In this randomised feasibility study, we recruited patients from seven centres in Italy, Spain, and Taiwan, who had solid tumours and acute respiratory failure and had a life expectancy of less than 6 months. We randomly allocated patients to receive either NIV (using the Pressure Support mode and scheduled on patients' request and mask comfort) or oxygen therapy (using a Venturi or a reservoir mask). We used a computer-generated sequence for randomisation, stratified on the basis of patients' hypercapnic status (PaCO2 >45 mm Hg or PaCO2 ≤45 mm Hg), and assigned treatment allocation using opaque, sealed envelopes. Patients in both groups were given sufficient subcutaneous morphine to reduce their dyspnoea score by at least one point on the Borg scale. Our primary endpoints were to assess the acceptability of NIV used solely as a palliative measure and to assess its effectiveness in reducing dyspnoea and the amount of opiates needed compared with oxygen therapy. Analysis was done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00533143. Findings: We recruited patients between Jan 15, 2008, and March 9, 2011. Of 234 patients eligible for recruitment, we randomly allocated 200 (85%) to treatment: 99 to NIV and 101 to oxygen. 11 (11%) patients in the NIV group discontinued treatment; no patients in the oxygen group discontinued treatment. Dyspnoea decreased more rapidly in the NIV group compared with the oxygen group (average change in Borg scale -0·58, 95% CI -0·92 to -0·23, p=0·0012), with most benefit seen after the first hour of treatment and in hypercapnic patients. The total dose of morphine during the first 48 h was lower in the NIV group than it was in the oxygen group (26·9 mg [37·3] for NIV vs 59·4 mg [SD 67·1] for oxygen; mean difference -32·4 mg, 95% CI -47·5 to -17·4). Adverse events leading to NIV discontinuation were mainly related to mask intolerance and anxiety. Morphine was suspended because of severe vomiting and nausea (one patient in each group), sudden respiratory arrest (one patient in the NIV group), and myocardial infarction (one patient in the oxygen group). Interpretation: Our findings suggest that NIV is more effective compared with oxygen in reducing dyspnoea and decreasing the doses of morphine needed in patients with end-stage cancer. Further studies are needed to confirm our findings and to assess the effectiveness of NIV on other outcomes such as survival. The use of NIV is, however, restricted to centres with NIV equipment, our findings are not generalisable to all cancer or palliative care units. Funding: None. © 2013 Elsevier Ltd.


Siracusa A.,University of Perugia | Folletti I.,University of Perugia | Moscato G.,Scientific Institute of Pavia
Current Opinion in Allergy and Clinical Immunology | Year: 2013

Purpose of Review: Recently there has been growing interest in non-IgE-mediated and irritant-induced occupational rhinitis due to old and new low-molecular-weight and irritant agents. The purpose of this review is to summarize the scientific evidence on agents and work activities responsible for non-IgE-mediated and irritant-induced occupational rhinitis and work-exacerbated rhinitis published in 2011 and 2012. Recent Findings: Several epidemiological, surveillance and experimental studies, case reports and reviews showed that workers exposed to drugs, wood dust, chemicals, metals and biocides are at high risk of non-IgE-mediated and irritant-induced occupational rhinitis; among activities at risk are healthcare, antibiotic manufacturing and cleaning workers. Work-exacerbated rhinitis has not been specifically studied, but it is reasonable to expect that it is frequently associated with work-exacerbated asthma. Recently, work-related anosmia/microsmia, nasal polyps and sinusitis have also been described. Reducing or eliminating workplace exposure to the specific agent has been confirmed to be effective in preventing symptoms of nonallergic occupational rhinitis. Summary: In consideration of the relevance of non-IgE-mediated and irritant-induced work-related rhinitis, physicians should recognize work-related rhinitis symptoms due to old and new low-molecular-weight and irritant agents. The mechanisms of non-IgE-mediated and irritant-induced occupational rhinitis remain largely unclear and need to be studied further. Substitution of responsible agents, reduction or elimination of exposure at the workplace should be enforced as effective measures. Copyright © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins.


Pettorossi V.E.,University of Perugia | Schieppati M.,University of Pavia | Schieppati M.,Scientific Institute of Pavia
Frontiers in Human Neuroscience | Year: 2014

This review article deals with some effects of neck muscle proprioception on human balance, gait trajectory, subjective straight-ahead (SSA), and self-motion perception. These effects are easily observed during neck muscle vibration, a strong stimulus for the spindle primary afferent fibers. We first remind the early findings on human balance, gait trajectory, SSA, induced by limb, and neck muscle vibration. Then, more recent findings on self-motion perception of vestibular origin are described. The use of a vestibular asymmetric yaw-rotation stimulus for emphasizing the proprioceptive modulation of motion perception from the neck is mentioned. In addition, an attempt has been made to conjointly discuss the effects of unilateral neck proprioception on motion perception, SSA, and walking trajectory. Neck vibration also induces persistent aftereffects on the SSA and on self-motion perception of vestibular origin. These perceptive effects depend on intensity, duration, side of the conditioning vibratory stimulation, and on muscle status. These effects can be maintained for hours when prolonged high-frequency vibration is superimposed on muscle contraction. Overall, this brief outline emphasizes the contribution of neck muscle inflow to the construction and fine-tuning of perception of body orientation and motion. Furthermore, it indicates that tonic neck-proprioceptive input may induce persistent influences on the subject’s mental representation of space. These plastic changes might adapt motion sensitiveness to lasting or permanent head positional or motor changes. © 2014 Pettorossi and Schieppati.


Cannavino J.,University of Pavia | Brocca L.,University of Pavia | Sandri M.,Venetian Institute of Molecular Medicine | Sandri M.,University of Pavia | And 4 more authors.
Journal of Physiology | Year: 2015

Key points: Skeletal muscle atrophy occurs as a result of disuse. Although several studies have established that a decrease in protein synthesis and increase in protein degradation lead to muscle atrophy, little is known about the triggers underlying such processes. A growing body of evidence challenges oxidative stress as a trigger of disuse atrophy; furthermore, it is also becoming evident that mitochondrial dysfunction may play a causative role in determining muscle atrophy. Mitochondrial fusion and fission have emerged as important processes that govern mitochondrial function and PGC-1α may regulate fusion/fission events. Although most studies on mice have focused on the anti-gravitary slow soleus muscle as it is preferentially affected by disuse atrophy, several fast muscles (including gastrocnemius) go through a significant loss of mass following unloading. Here we found that in fast muscles an early down-regulation of pro-fusion proteins, through concomitant AMP-activated protein kinase (AMPK) activation, can activate catabolic systems, and ultimately cause muscle mass loss in disuse. Elevated muscle PGC-1α completely preserves muscle mass by preventing the fall in pro-fusion protein expression, AMPK and catabolic system activation, suggesting that compounds inducing PGC-1α expression could be useful to treat and prevent muscle atrophy. The mechanisms triggering disuse muscle atrophy remain of debate. It is becoming evident that mitochondrial dysfunction may regulate pathways controlling muscle mass. We have recently shown that mitochondrial dysfunction plays a major role in disuse atrophy of soleus, a slow, oxidative muscle. Here we tested the hypothesis that hindlimb unloading-induced atrophy could be due to mitochondrial dysfunction in fast muscles too, notwithstanding their much lower mitochondrial content. Gastrocnemius displayed atrophy following both 3 and 7 days of unloading. SOD1 and catalase up-regulation, no H2O2 accumulation and no increase of protein carbonylation suggest the antioxidant defence system efficiently reacted to redox imbalance in the early phases of disuse. A defective mitochondrial fusion (Mfn1, Mfn2 and OPA1 down-regulation) occurred together with an impairment of OXPHOS capacity. Furthermore, at 3 days of unloading higher acetyl-CoA carboxylase (ACC) phosphorylation was found, suggesting AMP-activated protein kinase (AMPK) pathway activation. To test the role of mitochondrial alterations we used Tg-mice overexpressing PGC-1α because of the known effect of PGC-1α on stimulation of Mfn2 expression. PGC-α overexpression was sufficient to prevent (i) the decrease of pro-fusion proteins (Mfn1, Mfn2 and OPA1), (ii) activation of the AMPK pathway, (iii) the inducible expression of MuRF1 and atrogin1 and of authopagic factors, and (iv) any muscle mass loss in response to disuse. As the effects of increased PGC-1α activity were sustained throughout disuse, compounds inducing PGC-1α expression could be useful to treat and prevent muscle atrophy also in fast muscles. © 2015 The Physiological Society.


Cannavino J.,University of Pavia | Brocca L.,University of Pavia | Sandri M.,Venetian Institute of Molecular Medicine | Sandri M.,University of Pavia | And 3 more authors.
Journal of Physiology | Year: 2014

Key points: Oxidative stress is widely considered a major cause of muscle loss not only in disuse but also in most chronic diseases, triggering carbonylation of proteins and activation of catabolic pathways involved in their degradation. Here we show that administration of an antioxidant prevents redox imbalance, but does not prevent activation of catabolic pathways and muscle atrophy. We indicate that alterations of oxidative metabolism, occurring in slow soleus muscle, are not just a consequence of disuse, but a major cause of activation of catabolic pathways and loss of mass. This conclusion is confirmed by the observation that muscle-specific overexpression of PGC-1α, a master regulator of mitochondrial biogenesis, prevents activation of catabolic systems and disuse muscle atrophy. These findings contribute to a better mechanistic understanding of disuse muscle loss. Prolonged skeletal muscle inactivity causes muscle fibre atrophy. Redox imbalance has been considered one of the major triggers of skeletal muscle disuse atrophy, but whether redox imbalance is actually the major cause or simply a consequence of muscle disuse remains of debate. Here we hypothesized that a metabolic stress mediated by PGC-1α down-regulation plays a major role in disuse atrophy. First we studied the adaptations of soleus to mice hindlimb unloading (HU) in the early phase of disuse (3 and 7 days of HU) with and without antioxidant treatment (trolox). HU caused a reduction in cross-sectional area, redox status alteration (NRF2, SOD1 and catalase up-regulation), and induction of the ubiquitin proteasome system (MuRF-1 and atrogin-1 mRNA up-regulation) and autophagy (Beclin1 and p62 mRNA up-regulation). Trolox completely prevented the induction of NRF2, SOD1 and catalase mRNAs, but not atrophy or induction of catabolic systems in unloaded muscles, suggesting that oxidative stress is not a major cause of disuse atrophy. HU mice showed a marked alteration of oxidative metabolism. PGC-1α and mitochondrial complexes were down-regulated and DRP1 was up-regulated. To define the link between mitochondrial dysfunction and disuse muscle atrophy we unloaded mice overexpressing PGC-1α. Transgenic PGC-1α animals did not show metabolic alteration during unloading, preserving muscle size through the reduction of autophagy and proteasome degradation. Our results indicate that mitochondrial dysfunction plays a major role in disuse atrophy and that compounds inducing PGC-1α expression could be useful to treat/prevent muscle atrophy. © 2014 The Authors.


Manconi M.,Civic Hospital EOC of Lugano | Zavalko I.,Civic Hospital EOC of Lugano | Zavalko I.,Russian Academy of Sciences | Fanfulla F.,Scientific Institute of Pavia | And 2 more authors.
Sleep | Year: 2015

Study Objectives: Current sleep scoring rules exclude leg movements that occur near respiratory events from being scored as periodic leg movements during sleep (PLMS) but differ in whether they exclude leg movements occurring at the end (WASM/IRLSSG) or during a respiratory event (AASM). The aim of the present study was to describe the distribution of leg movements in relation to respiratory events and to contribute to an evidence-based rule for the identification and scoring of respiratory-related leg movements (RRLMs). Design: Retrospective chart review and analysis of polysomnographic recordings. Setting: Clinical sleep laboratory. Participants: 64 patients with polysomnographic recordings between January 2010 and July 2011, aged 18 to 75 years, with AHI > 20, ODI > 10, more than 50% of apneas being obstructive, > 15 leg movements of any type per hour of sleep, no more than 20% of total sleep time with artifacts and no medical condition or medication that could influence leg movements or respiratory disturbances. Interventions: None. Measurements and Results: Back-averaging of leg movement activity (LMA) with respect to respiratory events revealed that LMA was present shortly before the end of the respiratory events, but occurred mostly following respiratory events with peak onset of LMA 2.5 s after respiratory event termination. Increased LMA before the beginning of the respiratory event consisted mainly of the tail of LMA after the end of the previous respiratory event. Change-point analysis indicated that LMA was increased over an interval of -2.0 s to +10.25 s around the end of respiratory events. Changing the definition of RRLMs had a significant influence on PLMS counts. The number of patients with obstructive sleep apnea with PLMS index > 15 was 80% when considering the WASM/IRLSSG definition, 67% for the AASM criteria, and 41% when based on the interval identified by change-point analysis (-2.0 to 10.25 s). Conclusions: Leg movements are not augmented at the beginning or middle of respiratory events but are increased around the end of respiratory events over a period significantly longer than specified in the AASM and the WASM/IRLSSG rules. Both rules underestimate the number of respiratory-related leg movements and thus overestimate the number of periodic leg movements during sleep in patients with obstructive sleep apnea.


Fanfulla F.,Scientific Institute of Pavia | Camera A.,University of Pavia | Fulgoni P.,Scientific Institute of Pavia | Chiovato L.,University of Pavia | Nappi R.E.,University of Pavia
Sleep Medicine | Year: 2013

Background: Female sexual dysfunction (FSD) is diagnosed when an impairment in the sexual response cycle is associated with distress in women. The association between obstructive sleep apnea (OSA) and FSD has been poorly investigated with conflicting results. Aim: To assess the role of OSA in determining FSD in pre menopausal obese women. Methods: Forty-six women underwent standard polysomnography. Data on sexual function and sexual-related distress were obtained using the Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale (FSDS). Women with both abnormal FSFI and FSDS scores were classified as having FSD. Results: Thirty-one women were classified as having OSA. Fourteen (30.4%) women had both sexual difficulties and sexual distress resulting in FSD; they showed higher values of sleep time spent with SpO2 <90% (T90 16.8±24.4 vs. 3.2±5.2%; p=0.004). FSD was present in 10 women with OSA (32.2%); in this group T90 was higher (23.5±26.3) in women with FSD than in those without FSD (4.8±5.8; p=0.003). In a logistic multiple regression analysis, T90 was the only factor associated with an increased risk for FSD (odds ratio [OR] 1.07) (confidence interval [CI]) 1.006-1.13]; p=0.03). Conclusions: In premenopausal obese women the presence of FSD is correlated with OSA only when nocturnal hypoxia is present. © 2013 Elsevier B.V.


Buonocore M.,Scientific Institute of Pavia | Bodini A.,Scientific Institute of Pavia | Demartini L.,Scientific Institute of Pavia | Bonezzi C.,Scientific Institute of Pavia
Minerva Anestesiologica | Year: 2012

Background. Spinal cord stimulation (SCS) has been widely used for pain relief of patients with neuropathic chronic pain, frequently with only partial efficacy. Further advancements probably need a better understanding of SCS mechanisms, yet largely unknown. Aims of this paper were to answer the question if the lumbar SCS inhibits the tibial nerve somatosensory evoked potentials (SEPs) and to discuss the role of lemniscal afferents modulation in the antalgic mechanism of SCS. Methods. Ten consecutive patients successfully treated with implanted SCS devices for chronic pain in the lower limbs (four males, six females, age range 42-72 years) were enrolled. All the patients had an implanted system with an epidural lead connected to a pulse generator. The vertebral level ranged from T9 to T12. The cortical SEPs complex P39-N50-P60 was recorded at the basal (T0) evaluation, during the stimulation (T1) and immediately after the stimulation (T2). Results. In two of ten patients (20%) the complex P39-N50-P60 became unrelievable at the T1 control (stimulator on). In the remaining eight patients statistical analysis showed a significant reduction of the P39/N50 amplitude at T1 recording. In all patients considered, T0 and T2 recordings were not significantly different, suggesting a fast recovery of the SCS effect on SEPs. Conclusion. The results obtained in the present study show an inhibitory effect of SCS on SEPs and support the hypothesis that in some forms of neuropathic pain the antalgic effect of SCS could be attributed to the collision of action potentials travelling in opposite direction on peripheral large diameter fibres. © 2012 EDIZIONI MINERVA MEDICA.

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