46 research outputs found
Subthreshold bipolar atrial stimulation affects the discharge rate of the sinus node: an animal study
Aim of this study was to verify whether the electrical field generated inside the right atrium by sub-threshold electrical impulses (impulses unable to induce cells activation) may condition the discharge rate of the sinus node cells. An electrophysiological study was performed on seven young farm pigs before and after denervation. After general anesthesia, pigs were stimulated with impulses delivered at constant rate by a bipolar catheter positioned inside the right atrium. The amplitude of the stimulus was set to avoid atrial capture. A 10-minute atrial stimulation was performed at a rate above and below the spontaneous heart rate, both before and after denervation. Three animals showed a conditioning of the sinus rhythm, observed as phase synchronization. The different response, or even the no response, of animals to stimulation could be due to different factors, concerning biological, pharmacological and "geometric" conditions. The important result remains that a perturbation of the sinus rhythm can be induced by a very low electrical field, as the one generated by the activity of artificial pacemakers, and it could help explaining the onset of rhythm disturbances in paced patients
SYNCHRONIZATION INDUCED BY PACED ATRIAL SUBTHRESHOLD STIMULATION ON THE SINUS NODE ACTIVITY IN ANIMAL EXPERIMENT
Synchronization is the well-known phenomenon that indicates adjustment of frequencies of weakly interacting self-sustained periodic oscillators [1]. Besides the physics environment, synchronization is often encountered even in physiological systems exhibiting oscillatory behaviour. Above all others, the heart, the biological oscillator par excellence, has been object of a number of investigations. At the cellular level interesting experiments were carried out on spontaneously beating aggregates of cardiac cells from embryonic chicken heart stimulated with single impulse or impulses of different amplitudes and frequencies [2]. These experiments evidenced the interaction between stimuli and cardiac cells activity in terms of phase resetting (single stimulus) and synchronization (train of impulses). Aim of this study was to verify whether the electrical field generated inside the right atrium by subthreshold electrical impulses (impulses unable to induce cells activation) may condition the discharge rate of the sinus node cell
Case Report: Microangiopathic Hemolytic Anemia With Normal ADAMTS13 Activity
Thrombotic microangiopathies (TMAs) include a heterogeneous group of diseases characterized by abnormalities in the vessel walls of arterioles and capillaries resulting in microvascular thrombosis that typically presents with a microangiopathic hemolytic anemia (MAHA) and severe thrombocytopenia. We describe here the case of an 82-year-old woman, who came to our attention for a clinical condition consistent with thrombotic microangiopathy. Even if initially highly suggestive for a thrombotic thrombocytopenic purpura (TTP), the elevated ADAMTS13 activity together with the alteration of the main coagulation parameters (D-dimer elevation, fibrinogen consumption, slightly prolonged prothrombin time), induced us to consider several other diseases in the differential diagnostic process. The case evolved toward a suspected overlapped secondary hemophagocytic syndrome, though the hyperferritinemia was finally interpreted within the frame of a cytokine storm. After a complex diagnostic workup, the clinical and biochemical parameters guided us toward the diagnosis of a cancer-related microangiopathic hemolytic anemia (CR-MAHA) secondary to a relapsing breast cancer with multiple metastatic localizations. Prednisone 1 mg/kg body weight was started, and several units of fresh frozen plasma were infused, obtaining a good control of the hemolysis. No specific oncological therapies were, however, possible, due to the older age and the critically compromised general condition of the patient; therefore, after clinical stabilization, the patient was discharged for treatment in a palliative care Hospital
The Third Dose of BNT162b2 COVID-19 Vaccine Does Not “Boost” Disease Flares and Adverse Events in Patients with Rheumatoid Arthritis
Data on the risk of adverse events (AEs) and disease flares in autoimmune rheumatic diseases (ARDs) after the third dose of COVID-19 vaccine are scarce. The aim of this multicenter, prospective study is to analyze the clinical and immunological safety of BNT162b2 vaccine in a cohort of rheumatoid arthritis (RA) patients followed-up from the first vaccine cycle to the third dose. The vaccine showed an overall good safety profile with no patient reporting serious AEs, and a low percentage of total AEs at both doses (40/78 (51.3%) and 13/47 (27.7%) patients after the second and third dose, respectively (p < 0.002). Flares were observed in 10.3% of patients after the end of the vaccination cycle and 12.8% after the third dose. Being vaccinated for influenza was inversely associated with the onset of AEs after the second dose, at both univariable (p = 0.013) and multivariable analysis (p = 0.027). This result could allow identification of a predictive factor of vaccine tolerance, if confirmed in larger patient populations. A higher disease activity at baseline was not associated with a higher incidence of AEs or disease flares. Effectiveness was excellent after the second dose, with only 1/78 (1.3%) mild breakthrough infection (BI) and worsened after the third dose, with 9/47 (19.2%) BI (p < 0.002), as a probable expression of the higher capacity of the Omicron variants to escape vaccine recognition
Management of psoriatic arthritis: a consensus opinion by expert rheumatologists
Background: Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disease involving several articular and extra-articular structures. Despite the important progresses recently made in all of the aspects of this disease, its management is still burdened by unresolved issues. The aim of this exercise was to provide a set of statements that may be helpful for the management of PsA. Methods: A group of 38 Italian rheumatologists with recognized expertise in PsA selected and addressed the following four topics: "early PsA," "axial-PsA," "extra-articular manifestations and comorbidities," "therapeutic goals." Relevant articles from the literature (2016-2022) were selected by the experts based on a PubMed search. A number of statements for each topic were elaborated. Results: Ninety-four articles were selected and evaluated, 68 out of the 1,114 yielded by the literature search and 26 added by the Authors. Each of the four topic was subdivided in themes as follows: transition from psoriasis to PsA, imaging vs. CASPAR criteria in early diagnosis, early treatment for "early PsA"; axial-PsA vs. axialspondyloarthritis, diagnosis, clinical evaluation, treatment, standard radiography vs. magnetic resonance imaging for "axial PsA"; influence of inflammatory bowel disease on the therapeutic choice, cardiovascular comorbidity, bone damage, risk of infection for "comorbidities and extra-articular manifestations"; target and tools, treat-to-target strategy, role of imaging for "therapeutic goals." The final document consisted of 49 statements. Discussion: The final product of this exercise is a set of statements concerning the main issues of PsA management offering an expert opinion for some unmet needs of this complex disease
Surface CD52, CD84, and PTGER2 mark mature PMN-MDSCs from cancer patients and G-CSF-treated donors
Precise molecular characterization of circulating polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) is hampered by their mixed composition of mature and immature cells and lack of specific markers. Here, we focus on mature CD66b+CD10+CD16+CD11b+ PMN-MDSCs (mPMN-MDSCs) from either cancer patients or healthy donors receiving G-CSF for stem cell mobilization (GDs). By RNA sequencing (RNA-seq) experiments, we report the identification of a distinct gene signature shared by the different mPMN-MDSC populations under investigation, also validated in mPMN-MDSCs from GDs and tumor-associated neutrophils (TANs) by single-cell RNA-seq (scRNA-seq) experiments. Analysis of such a gene signature uncovers a specific transcriptional program associated with mPMN-MDSC differentiation and allows us to identify that, in patients with either solid or hematologic tumors and in GDs, CD52, CD84, and prostaglandin E receptor 2 (PTGER2) represent potential mPMN-MDSC-associated markers. Altogether, our findings indicate that mature PMN-MDSCs distinctively undergo specific reprogramming during differentiation and lay the groundwork for selective immunomonitoring, and eventually targeting, of mature PMN-MDSCs