423 research outputs found

    Unconventional dc transport in Rashba electron gases

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    We discuss the transport properties of a disordered two-dimensional electron gas with strong Rashba spin-orbit coupling. We show that in the high-density regime where the Fermi energy overcomes the energy associated with spin-orbit coupling, dc transport is accurately described by a standard Drude's law, due to a non-trivial compensation between the suppression of back-scattering and the relativistic correction to the quasi-particle velocity. On the contrary, when the system enters the opposite dominant spin-orbit regime, Drude's paradigm breaks down and the dc conductivity becomes strongly sensitive to the spin-orbit coupling strength, providing a suitable tool to test the entanglement between spin and charge degrees of freedom in theseComment: 6 pages, 4 figures+Supplemental Material. To appear in Phys. Rev. Let

    Rubber hand illusion induced by touching the face ipsilaterally to a deprived hand: evidence for plastic "somatotopic" remapping in tetraplegics

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    Background: Studies in animals and humans indicate that the interruption of body-brain connections following spinal cord injury (SCI) leads to plastic cerebral reorganization.Objective: To explore whether inducing the Rubber Hand Illusion (RHI) via synchronous multisensory visuo-tactile bodily stimulation may reveal any perceptual correlates of plastic remapping in SCI.Methods: In 16 paraplegic, 16 tetraplegic and 16 healthy participants we explored whether RHI may be induced by tactile stimuli involving not only the left hand but also the left hemi-face. Touching the participants actual hand or face was either synchronous or asynchronous with tactile stimuli seen on a rubber hand. We assessed two components of the illusion, namely perceived changes in the real hand in space (indexed by proprioceptive drift) and ownership of the rubber hand (indexed by subjective responses to an ad-hoc questionnaire).Results: Proprioceptive drift and ownership were found in the healthy group only in the condition where the left real and fake hand were touched simultaneously. In contrast, no drift was found in the SCI patients who, however, showed ownership after both synchronous and asynchronous hand stroking. Importantly, only tetraplegics showed the effect also after synchronous face stroking.Conclusions: RHI may reveal plastic phenomena in SCI. In hand representation-deprived tetraplegics, stimuli on the face (represented contiguously in the somatic and motor systems), drive the sense of hand ownership. This hand-face remapping phenomenon may be useful for restoring a sense of self in massively deprived individuals

    Psoriasis and psoriasiform reactions secondary to immune checkpoint inhibitors

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    The advent of Immune Checkpoint Inhibitors (ICIs) as a standard of care for several cancers, including melanoma and head/neck squamous cell carcinoma has changed the therapeutic approach to these conditions, drawing at the same time the attention on some safety issues related to their use. To assess the incidence of psoriasis as a specific immune-related cutaneous adverse event attributing to ICIs using the Eudravigilance reporting system. All reports of adverse drug reactions (ADRs) concerning either exacerbation of psoriasis or de novo onset of psoriasis/psoriasiform reactions associated to the use of Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) inhibitors ipilimumab and tremelimumab, and the Programmed cell Death protein 1/Programmed Death-Ligand 1 (PD-1/PD-L1) inhibitors nivolumab, pembrolizumab, atezolizumab, durvalumab, avelumab, and cemiplimab were identified and extracted from the Eudravigilance reporting system, during the period between the date of market licensing (for each study drug) and 30 October 2020. 8213 reports of cutaneous ADRs associated with at least one of study drug have been recorded, of which 315 (3.8%) reporting psoriasis and/or psoriasiform reactions as ADR. In 70.8% of reports patients had pre-existing disease. ICIs-related skin toxicity is a well-established phenomenon, presenting with several conditions, sustained by an immune background based on the activity of some cells (CD4+/CD8+ T-cells, neutrophils, eosinophils, and plasmocytes), inflammatory mediators, chemokines, and tumor-specific antibodies. In this setting, psoriasis represents probably the most paradigmatic model of these reactions, thus requiring adequate recognition as no guidelines on management are now available

    Role of Pten deletion and BRafV600E mutation in the generation of testicular germ cell tumors

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    Testicular germ cell tumors (TGCT) represent the most common solid malignancy affecting males between the ages of 15 and 35, while ovarian germ cell tumours (OGCT) are a type of ovarian neoplasm principally affecting young women. Germ cell tumors (GCTs) account for about 95 % of testicular cancer cases and for only 2-3% of ovarian cancer cases (Siegel et al., 2011). Most TGCT are potentially curable, however approximately 5% of patients with TGCT develop chemoresistance and die from the disease. PTEN deletion and mutational activation of BRAF are frequent genetic alterations found in human TGCTs, suggesting that they might be directly involved in germ cell tumorigenesis. Furthermore, BRAF mutation positively correlates with the acquisition of resistence to cisplatin, the most commonly chemotherapic agent employed for the treatment of human TGCTs. We obtained heterozygous floxed Ptenloxp/+ BRafCA Spo11Cre mice showing ovarian teratomas and testicular tumors with an incidence of about 30% at 20 days post partum (dpp) . Since Spo- 11Cre is active at around 13.5 days post coitum (dpc) in female germ cells and at around 7 dpp in male germ cells (18), these results suggest that ovarian teratomas origin from early meiotic germ cells in the fetal period whereas GCT formation in males can be a postnatal event. By histological inspection, we found that cancer cells in testes showed features reminiscent of seminoma such as a diffuse, confluent multinodular pattern. However, by immunohistochemical staining, we observed that the cells within the tumor showed heterogeneous positivity for the pluripotency markers Oct4, Sox2, Nanog, Kit and Prdm14, suggesting that they can represent a mixed form of seminoma and embryonal carcinoma cells. Our results indicate that deregulated MAP and PI3 Kinase activation can lead to postnatal male germ cells transformation

    Deoxypyrimidine monophosphate bypass therapy for thymidine kinase 2 deficiency.

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    Autosomal recessive mutations in the thymidine kinase 2 gene (TK2) cause mitochondrial DNA depletion, multiple deletions, or both due to loss of TK2 enzyme activity and ensuing unbalanced deoxynucleotide triphosphate (dNTP) pools. To bypass Tk2 deficiency, we administered deoxycytidine and deoxythymidine monophosphates (dCMP+dTMP) to the Tk2 H126N (Tk2(-/-)) knock-in mouse model from postnatal day 4, when mutant mice are phenotypically normal, but biochemically affected. Assessment of 13-day-old Tk2(-/-) mice treated with dCMP+dTMP 200 mg/kg/day each (Tk2(-/-200dCMP/) (dTMP)) demonstrated that in mutant animals, the compounds raise dTTP concentrations, increase levels of mtDNA, ameliorate defects of mitochondrial respiratory chain enzymes, and significantly prolong their lifespan (34 days with treatment versus 13 days untreated). A second trial of dCMP+dTMP each at 400 mg/kg/day showed even greater phenotypic and biochemical improvements. In conclusion, dCMP/dTMP supplementation is the first effective pharmacologic treatment for Tk2 deficiency

    Considerations on surgery invasiveness and response and toxicity patterns in classic palliative radiotherapy for acrometastases of the hand: a hint for a potential role of stereotactic body radiation therapy? A case report and literature review

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    BackgroundThe rarity of hand acrometastases hampers the consensus-building for their optimal management among the involved oncology professionals. In the current literature, demolitive surgery overcomes the use of palliative radiotherapy, which proved to be ineffective in more than 30% of cases treated with classic palliative dose schemes, carrying also a not negligible radiation-related adverse event rate. Against this background, stereotactic body radiation therapy (SBRT) could emerge as a well-balanced therapeutic option.Case summaryHere we describe the methods and outcomes of a SBRT treatment of a painful and function-limiting hand acrometastasis in a patient with a history of stage IIIB lung adenocarcinoma. We delivered a total dose of 30 Gy in five daily fractions to a soft-tissue metastasis abutting the fifth metacarpal bone through the SBRT protocol generally used for intracranial treatments. A few weeks later, the patient reported a clinical complete response with acrometastasis and pain disappearance, function recovery, and no significant toxicity. The acrometastasis was the first sign of an atypical cancer progression.ConclusionsSBRT for hand acrometastases is feasible and might have the best therapeutic profile among the currently available treatment options for this rare clinical scenario. Larger investigations are needed to confirm the present single-case experience

    Superinfections caused by carbapenem-resistant Enterobacterales in hospitalized patients with COVID-19: a multicentre observational study from Italy (CREVID Study)

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    Objectives To describe clinical characteristics and outcomes of COVID-19 patients who developed secondary infections due to carbapenem-resistant Enterobacterales (CRE). Methods Retrospective observational study including COVID-19 patients admitted to 12 Italian hospitals from March to December 2020 who developed a superinfection by CRE. Superinfection was defined as the occurrence of documented bacterial infection >48 h from admission. Patients with polymicrobial infections were excluded. Demographic, clinical characteristics and outcome were collected. Isolates were classified as KPC, metallo-beta-lactamase (MBL) and OXA-48-producing CRE. A Cox regression analysis was performed to identify factors independently associated with 30 day mortality. Results Overall, 123 patients (median age 66 years, IQR 59-75) were included. The majority of infections occurred in the ICU (81, 65.9%), while 42 (34.1%) in medical wards. The most common types of infection were bloodstream infections (BSI) (n = 64, 52%), followed by urinary-tract infections (UTI) (n = 28, 22.8%), hospital-acquired/ventilator-associated pneumonia (HAP/VAP) (n = 28, 22.8%), intra-abdominal infections (n = 2, 1.6%) and skin infections (n = 1, 0.8%). Sixty-three (51.2%) infections were caused by KPC-, 54 (43.9%) by MBL-, and 6 (4.8%) by OXA-48-producing CRE. Thirty-day mortality was 33.3% (41/123). On Cox regression analysis, HAP/VAP compared with UTI (HR 7.23, 95% CI 2.09-24.97, P = 0.004), BSI compared with UTI (HR 3.96, 95% CI, 1.33-11.77, P = 0.004), lymphopenia on admission (HR 3, 95% CI 1.44-6.26, P = 0.003) and age (HR 1.05, 95% CI 1.02-1.08, P = 0.002) were predictors of 30 day mortality. Conclusions Superinfections by CRE were associated with high risk of 30 day mortality in patients with COVID-19. HAP/VAP was the strongest predictor of death in these patients
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