396 research outputs found

    The effects of the friend networking site MySpace on adolescents\u27 global self esteem

    Get PDF
    The purpose of this study was to examine the effects of the popular friend-networking site, MySpace on young adolescents\u27 global self-esteem. The hypothesis of the present study states that adolescents who spend more time on the friend-networking site, MySpace, will experience lower overall self-esteem than their peers who spend either less time on the site, or no time on the site. Further, predictions were made on the basis of gender, suggesting that adolescent girls with adequate access will be more likely to experience these affects than will their male counterparts. Participants in this study were 95 (31 males, 64 females) seventh and eighth grade students from two middle class, suburban communities. The Rosenberg Self Esteem Scale (SES) was administered to all participants to measure global self-esteem. A Two-Way between-subjects ANOVA was performed to determine the results of the study. The results revealed that there was no significant relationship between participants\u27 MySpace use and their self-esteem. These results suggest that the amount of time adolescents spend on MySpace does not directly affect their global self-esteem. Results also revealed no differences between genders, suggesting that in the sample population of this study, males and females view themselves in relatively the same way

    Ablation of Calsequestrin-1, Ca2+ unbalance, and susceptibility to heat stroke

    Get PDF
    Introduction: Ca2+ levels in adult skeletal muscle fibers are mainly controlled by excitation-contraction (EC) coupling, a mechanism that translates action potentials in release of Ca2+ from the sarcoplasmic reticulum (SR) release channels, i.e. the ryanodine receptors type-1 (RyR1). Calsequestrin (Casq) is a protein that binds large amounts of Ca2+ in the lumen of the SR terminal cisternae, near sites of Ca2+ release. There is general agreement that Casq is not only important for the SR ability to store Ca2+, but also for modulating the opening probability of the RyR Ca2+ release channels. The initial studies: About 20 years ago we generated a mouse model lacking Casq1 (Casq1-null mice), the isoform predominantly expressed in adult fast twitch skeletal muscle. While the knockout was not lethal as expected, lack of Casq1 caused a striking remodeling of membranes of SR and of transverse tubules (TTs), and mitochondrial damage. Functionally, CASQ1-knockout resulted in reduced SR Ca2+ content, smaller Ca2+ transients, and severe SR depletion during repetitive stimulation. The myopathic phenotype of Casq1-null mice: After the initial studies, we discovered that Casq1-null mice were prone to sudden death when exposed to halogenated anaesthetics, heat and even strenuous exercise. These syndromes are similar to human malignant hyperthermia susceptibility (MHS) and environmental-exertional heat stroke (HS). We learned that mechanisms underlying these syndromes involved excessive SR Ca2+ leak and excessive production of oxidative species: indeed, mortality and mitochondrial damage were significantly prevented by administration of antioxidants and reduction of oxidative stress. Though, how Casq1-null mice could survive without the most important SR Ca2+ binding protein was a puzzling issue that was not solved. Unravelling the mystery: The mystery was finally solved in 2020, when we discovered that in Casq1-null mice the SR undergoes adaptations that result in constitutively active store-operated Ca2+ entry (SOCE). SOCE is a mechanism that allows skeletal fibers to use external Ca2+ when SR stores are depleted. The post-natal compensatory mechanism that allows Casq1-null mice to survive involves the assembly of new SR-TT junctions (named Ca2+ entry units) containing Stim1 and Orai1, the two proteins that mediate SOCE

    Store-Operated Ca 2+ Entry in Skeletal Muscle Contributes to the Increase in Body Temperature during Exertional Stress

    Get PDF
    Exertional heat stroke (HS) is a hyperthermic crisis triggered by an excessive accumulation of Ca2+ in skeletal muscle fibers. We demonstrated that exercise leads to the formation of calcium entry units (CEUs), which are intracellular junctions that reduce muscle fatigue by promoting the recovery of extracellular Ca2+ via store-operated Ca2+ entry (SOCE). Here, we tested the hypothesis that exercise-induced assembly of CEUs may increase the risk of HS when physical activity is performed in adverse environmental conditions (high temperature and humidity). Adult mice were: (a) first, divided into three experimental groups: control, trained-1 month (voluntary running in wheel cages), and acutely exercised-1 h (incremental treadmill run); and (b) then subjected to an exertional stress (ES) protocol, a treadmill run in an environmental chamber at 34â—¦C and 40% humidity. The internal temperature of the mice at the end of the ES was higher in both pre-exercised groups. During an ES ex-vivo protocol, extensor digitorum longus(EDL) muscles from the trained-1 month and exercised-1 h mice generated greater basal tension than in the control and were those that contained a greater number of CEUs, assessed by electron microscopy. The data collected suggest that the entry of Ca2+ from extracellular space via CEUs could contribute to exertional HS when exercise is performed in adverse environmental conditions

    The SMAD pathway is required for hepcidin response during endoplasmic reticulum stress

    Get PDF
    Hepcidin, the iron hormone, is regulated by a number of stimulatory and inhibitory signals. The cAMP responsive element binding protein 3-like 3, CREB3L3, mediates hepcidin response to endoplasmic reticulum (ER) stress. In this study we asked whether hepcidin response to ER stress also requires the SMAD1/5/8 pathway that has a major role in hepcidin regulation in response to iron and other stimuli. We analyzed hepcidin mRNA expression and promoter activity in response to ER stressors in HepG2 cells in the presence of the BMP type I receptor inhibitor LDN-193189, mutated hepcidin promoter or siRNA against different SMAD proteins. We then used a similar approach in vivo in wild-type, Smad1/5 or Creb3l3 -/- animals undergoing ER stress. In vitro, LDN-193189 prevented hepcidin mRNA induction by different ER stressors. Seemingly, mutation of a BMP-responsive element in the hepcidin promoter prevented ER stress-mediated upregulation. Moreover, in vitro silencing of SMAD proteins by siRNA, in particular SMAD5, blunted hepcidin response to ER stress. On the contrary, hepcidin induction by ER stress was maintained when using antibodies against canonical BMP receptor ligands. In vivo, hepcidin was induced by ER stress and prevented by LDN-193189. In addition, in Smad1/5 knock-out mice, ER stress was unable to induce hepcidin expression. Finally, in Creb3l3 knock-out mice, in response to ER stress, SMAD1/5 were correctly phosphorylated and hepcidin induction was still appreciable, although to a lesser extent as compared to control mice. In conclusion, our study indicates that hepcidin induction by ER stress involves the central regulatory SMAD1/5 pathway

    Tiny percutaneous needle biopsy: An efficient methodfor studying cellular and molecular aspectsof skeletal muscle in humans

    Get PDF
    Needle biopsy is widely used to obtain specimens for physiological, anatomical and biochemical studies of skeletal muscle (SM). We optimized a procedure which we termed tiny percutaneous needle biopsy (TPNB), to efficiently gather good numbers of human satellite cells and single dissociated fibers for the functional study of skeletal muscle; these samples permit isolation of high-quality RNA and sufficient amounts of proteins to allow molecular analysis. Moreover, TPNB showed a clear advantage in that the technique was easier than other procedures used on healthy volunteers in human trials. TPNB is a very safe minor surgical procedure. It is less traumatic than needle aspiration biopsy, and significant complications are improbable. TPNB should become established as an important tool in the investigation of SM and may be employed to study various physiological aspects of SM in human subjects. We suggest that TPNB should also be used in the study of muscle diseases and disorders including muscular dystrophy, congenital myopathy, and metabolic defects

    Efficacy and microbiota modulation induced by limpial 2.5%, a new medical device for the inverse psoriasis treatment

    Get PDF
    (1) Inverse psoriasis (IP), also known as intertriginous, typically affects the groin, armpits, navel, intergluteal fissure, and external genitalia. Skin lesions are erythematous plaques of inflammatory nature, smooth, well-delimited, non-scaly, and non-infiltrated. Lesions may be accompanied by itching, pain, or burning sensation. The aim of this study is both to investigate the modulation of the skin microbiota induced by IP and, on the other hand, to test the effectiveness of the new biotechnological product LimpiAL 2.5%. (2) Patients affected by IP were recruited in a private practice and treated for 4 weeks with LimpiAL 2.5% exclusively. The clinical effects on the lesion skin were evaluated, and the skin microbiotas before and after treatment were compared. (3) The clinical outcomes reveled a significant beneficial effect of the tested product. At the same time, LimpiAL increased the biological diversity of the skin microbiota and exerted a significant decrease of some Corynebacterium species, and the increase of some Staphylococcus species. (4) Together, the clinical outcomes and the microbiota analysis suggest that LimpiAL treatment improves the skin condition of affected patients, basically restoring the eubiosis conditions of the affected sites and modulating the bacterial composition of the resident microbiota

    Signal transduction events induced by extracellular guanosine 5′triphosphate in excitable cells

    Get PDF
    A better understanding of the physiological effects of guanosine-based purines should help clarify the complex subject of purinergic signalling. We studied the effect of extracellular guanosine 5′triphosphate (GTP) on the differentiation of two excitable cell lines that both have specific binding sites for GTP: PC12 rat pheochromocytoma cells and C2C12 mouse skeletal muscle cells. PC12 cells can be differentiated into fully functional sympathetic-like neurons with 50′00 ng ml−1 of nerve growth factor, whereas serum starvation causes C2C12 cells to differentiate into myotubes showing functional excitation–contraction coupling, with the expression of myosin heavy chain proteins. Our results show that GTP enhances the differentiation of both of these excitable cell lines. The early events in guanosine-based purine signal transduction appear to involve an increase in intracellular Ca2+ levels and membrane hyperpolarization. We further investigated the early activation of extracellular-regulated kinases and phosphoinositide 3-kinase in GTP-stimulated PC12 and C2C12 cells, respectively. We found that GTP promotes the activation of both kinases. Together, our results suggest that, even if there are some differences in the signalling pathways, GTP-induced differentiation in both cell lines is dependent on an increase in intracellular Ca2+

    Subclinical liver fibrosis in patients with idiopathic 1 pulmonary fibrosis.

    Get PDF
    Background - Data on the presence of subclinical fibrosis across multiple organs in patients with idiopathic lung fibrosis (IPF) are lacking. Our study aimed at investigating through hepatic transient elastography (HTE) the prevalence and clinical impact of subclinical liver fibrosis in a cohort of patients with IPF. Methods - Patients referred to the Centre for Rare Lung Disease of the University Hospital of Modena (Italy) from March 2012 to February 2013with established diagnosis of IPF and without a documented history of liver diseases were consecutively enrolled and underwent HTE. Based on hepatic stiffness status as assessed through METAVIR score patients were categorized as \u201c with liver fibrosis \u201d (corresponding to a METAVIR score of F1-F4) and \u201c without liver fibrosis\u201d (METAVIR F0). Potential predictors of liver fibrosis were investigated through logistic regression model among clinical and serological variables. The overall survival (OS) was assessed according to liver fibrosis and multivariate Cox regression analysis was used to identify independent predictors. Results - In 13 out of 37 patients (35%) with IPF a certain degree of liver fibrosis was documented.No correlation was found between liver stiffness and clinical-functional parameters. OS was lower in patients \u2018 with liver fibrosis\u2019 than in patients \u2018 without liver fibrosis\u2019 (median months 33[23-55] vs. 63[26-94], p=0.038). Patients \u2018 with liver fibrosis\u2019 presented a higher risk of death at seven years as compared to patients \u2018without liver fibrosis\u2019 (HR=2.6, 95%CI[1.003\u20136.7],p= 0.049). Higher level of AST to platelet ratio Index (APRI)was an independent predictor of survival (HR=4.52 95%CI[1.3\u201315.6], p=0.02). Conclusions - In our cohort, more than one third of IPF patients had concomitant subclinical liver fibrosis that negatively affected OS. These preliminary claims further investigation aimed at clarifying the mechanisms beyond multiorgan fibrosis and its clinical implication in patients with IPF

    Randomised controlled trial comparing efficacy and safety of high versus low Low-Molecular Weight Heparin dosages in hospitalized patients with severe COVID-19 pneumonia and coagulopathy not requiring invasive mechanical ventilation (COVID-19 HD): a structured summary of a study protocol.

    Get PDF
    To assess whether high doses of Low Molecular Weight Heparin (LMWH) (i.e. Enoxaparin 70 IU/kg twice daily) compared to standard prophylactic dose (i.e., Enoxaparin 4000 IU once day), in hospitalized patients with COVID19 not requiring Invasive Mechanical Ventilation [IMV], are: a)more effective in preventing clinical worsening, defined as the occurrence of at least one of the following events, whichever comes first: 1.Death2.Acute Myocardial Infarction [AMI]3.Objectively confirmed, symptomatic arterial or venous thromboembolism [TE]4.Need of either: a.Continuous Positive Airway Pressure (Cpap) or Non-Invasive Ventilation (NIV) orb.IMV in patients who at randomisation were receiving standard oxygen therapy5.IMV in patients who at randomisation were receiving non-invasive mechanical ventilationb)Similar in terms of major bleeding risk TRIAL DESIGN: Multicentre, randomised controlled, superiority, open label, parallel group, two arms (1:1 ratio), in-hospital study

    Development of post-COVID-19 cardiovascular events: An analysis of clinical features and risk factors from a single hospital retrospective study

    Get PDF
    Cardiovascular complications after a SARS-CoV-2 infection are a phenomenon of relevant scientific inter-est. The aim of this study was to analyze the onset of post-COVID-19 cardiovascular events in patients hospitalized in a tertiary care center. This is a retrospective study conducted on patients hospitalized over a period of three months. The patients were older than 18 years of age and had a diagnosis of COVID-19 infection confirmed from a nasopharyngeal swab sample. Anamnestic and clinical-laboratory data were collected. Cardiovascular events at 30 days were defined as follows: arrhythmias, myocardial infarction, myocarditis, and pulmonary embolism. Univariate analysis (Student\u2019s t-test or Mann-Whitney U test, as appropriate) and multivariate analysis (multinomial logistic regression) were applied to the data. A total of 394 patients were included; they were mostly males and had a median age of 65.5 years. Previous cardiovascular disease was present in 14.7% of patients. Oxygen therapy was required for 77.9%, and 53% received anticoagulant therapy. The overall 30-day mortality was 20.3%. A cardiovascular event developed in 15.7% of the subjects. These were mainly pulmonary embolism (9.4%), followed by arrhythmias (3.3%), myocardial infarction (2.3%), and myocarditis (0.8%). Patients who developed cardiovascular events upon univariate analysis were significantly older, with major comorbidities, a more compromised respiratory situation, and a higher mortality rate. Multivariate analysis revealed independent factors that were significantly associated with the development of cardiovascular events: hypertension, endotracheal intubation, and age older than 75 years. In patients with COVID-19, the development of a cardiovascular event occurs quite frequently and is mainly seen in elderly subjects with comorbidities (especially hypertension) in the presence of a severe respiratory picture
    • …
    corecore