In patients with distal symmetric polyneuropathy we assessed non-nociceptive Aβ- and nociceptive Aδ-afferents to investigate their role in the development of neuropathic pain. We screened 2240 consecutive patients with sensory disturbances and collected 150 patients with distal symmetric polyneuropathy (68 with pain and 82 without). All patients underwent the Neuropathic Pain Symptom Inventory to rate ongoing, paroxysmal and provoked pains, a standard nerve conduction study (NCS) to assess Aβ-fibre function, and laser-evoked potentials (LEPs) to assess Aδ-fibre function. Patients with pain had the same age (P > 0.50), but a longer delay since symptom onset than those without (P < 0.01). Whereas the LEP amplitude was significantly lower in patients with pain than in those without (P < 0.0001), NCS data did not differ between groups (P > 0.50). LEPs were more severely affected in patients with ongoing pain than in those with provoked pain (P < 0.0001). Our findings indicate that the impairment of Aβ-fibres has no role in the development of ongoing or provoked pain. In patients with ongoing pain the severe LEP suppression and the correlation between pain intensity and LEP attenuation may indicate that this type of pain reflects damage to nociceptive axons. The partially preserved LEPs in patients with provoked pain suggest that this type of pain is related to the abnormal activity arising from partially spared and sensitised nociceptive terminals. Because clinical and neurophysiological abnormalities followed similar patterns regardless of aetiology, pain should be classified and treated on mechanism-based grounds.
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Carpal tunnel syndrome (CTS), a common entrapment neuropathy involving the median nerve at the wrist, frequently manifests with neuropathic pain. We sought information on pain mechanisms in CTS. We studied 70 patients with a diagnosis of CTS (117 CTS hands). We used the DN4 questionnaire to select patients with neuropathic pain, and the Neuropathic Pain Symptom Inventory (NPSI) to assess the intensity of the various qualities of neuropathic pain. All patients underwent a standard nerve conduction study (NCS) to assess the function of non-nociceptive Abeta-fibres, and the cutaneous silent period (CSP) after stimulation of the IIIrd and Vth digits, to assess the function of nociceptive Adelta-fibres. In 40 patients (75 CTS hands) we also recorded laser-evoked potentials (LEPs) in response to stimuli delivered to the median nerve territory and mediated by nociceptive Adelta-fibres. We sought possible correlations between neurophysiological data and the various qualities of neuropathic pain as assessed by the NPSI. We found that the median nerve sensory conduction velocity correlated with paroxysmal pain and abnormal sensations, whereas LEP amplitude correlated with spontaneous constant pain. Our findings suggest that whereas paroxysmal pain and abnormal sensations reflect demyelination of non-nociceptive Abeta-fibres, spontaneous constant pain arises from damage to nociceptive Adelta-fibres.
The electrodeposition of zinc coatings is one of the most common surface treatments for providing corrosion resistance to metallic components. From the thermodynamic point of view, zinc is located in a sweet spot, with its reduction potential being lower than most other common metals, while at the same time being not too susceptible to atmospheric corrosion; overall these features make zinc the ideal candidate for the electroplating of sacrificial coatings for corrosion protection. Owing it to its low cost and scalability, zinc electroplating has cemented itself as a cornerstone process in a variety of industrial sectors in the last decades. [1] While zinc coatings corrosion resistance has proved to be satisfactory in most cases, it could still be improved to operate even in more aggressive environments. For this purpose, electrodeposition of zinc alloys with transition metals from the iron group (Ni, Co, Fe) has proven to be a successful method to enhance zinc coatings corrosion resistance. In particular, zinc-nickel alloys have found the greater success among them, due to improved corrosion resistance and mechanical properties. [2] Zinc-chromium alloys also present a good opportunity to improve coatings performance, thanks to the passivating effect of Cr. In fact, electrodeposited ZnCr alloys with a Cr content up to 10.4% were found to exhibit a corrosion potential shifted by up 150 mV in the anodic direction with respect to the pure zinc counterpart. [3] This shift led to a significant decrease in the coating dissolution rate but was sufficiently small that the layers could still preserve their sacrificial nature towards the underlying steel. In this work, ZnCr coatings are deposited on low carbon steel from an acidic sulfate formulation containing Cr(III) ions at various concentrations. The properties of ZnCr coatings are explored by varying the most common parameters such as current density, composition, and pH. Furthermore, the resulting coatings are characterized through conventional surface analysis techniques such as SEM, EDS, XRD and XRF. Finally, the corrosion resistance performance of the ZnCr coatings is compared to pure Zn coatings to highlight the benefits of the alloy. Bibliography [1] R. Winand, “Electrodeposition of Zinc and Zinc Alloys,” Mod. Electroplat. Fifth Ed. , pp. 285–307, Feb. 2011. [2] N. Lotfi, M. Aliofkhazraei, H. Rahmani, and G. B. Darband, “Zinc–Nickel Alloy Electrodeposition: Characterization, Properties, Multilayers and Composites,” Prot. Met. Phys. Chem. Surfaces , vol. 54, no. 6, pp. 1102–1140, Nov. 2018. [3] V. Chakarova, T. Boiadjieva-Scherzer, D. Kovacheva, H. Kronberger, and M. Monev, “Corrosion behaviour of electrodeposited Zn-Cr alloy coatings,” Corros. Sci. , vol. 140, pp. 73–78, Aug. 2018.
Background Patients with dementia may have limited capacity to give informed consent to participate in clinical research. One possible way to safeguard the patients' interests in research is the involvement of a proxy in the recruitment process. In Italy, the system of proxy is determined by the courts. In this study we evaluate the timing for appointment of a legal proxy in Italy and identify predictive variables of appointment. Methodology/Principal Findings Subjects were recruited among the outpatients seeking medical advice for cognitive complaints at the Centre for Research and Treatment of Cognitive Dysfunctions, University of Milan, “Luigi Sacco” Hospital. The Centre was participating to the AdCare Study, a no-profit randomised clinical trial coordinated by the Italian National Institute of Health. The requirement that informed consent be given by a legal representative dramatically slowed down the recruitment process in AdCare, which was prematurely interrupted. The Centre for Research and Treatment of Cognitive Dysfunctions collected data on the timing required to appoint the legal representatives. Patients diagnosed with dementia and their caregivers were provided information on the Italian law on legal agency (law 6/2004). At each scheduled check-up the caregiver was asked whether she/he had applied to appoint a legal proxy for the patient and the time interval between the presentation of the law, the registration of the application at the law court chancellery and the sentence of appointment was registered. The study involved 169 demented patients. Seventy-eight patients (46.2%) applied to appoint a legal proxy. These subjects were usually younger, had been suffering from dementia for a longer time, had less than two children and made more use of memantine. The mean interval time between the presentation of the law and the patients' application to the law court chancellery was two months. The mean interval time between the patient's application to the law court chancellery and the sentence of appointment was four months. Conclusions/Significance In Italy the requirement that legal representatives be appointed by the courts slows down subjects' participation in research. Other procedures for legal agency of the incapacitated patients may be adopted, taking as examples other EU countries' systems.
