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Leme E, Silva E, Rodrigues P, Silva I, Bondan E, Martins M, Bernardi M, Kirsten T. Astroglial reaction and behavioural changes in zebrafish exposed to water samples from the billings drinking supply reservoir (São Paulo, Brazil). J Comp Pathol 2019. [DOI: 10.1016/j.jcpa.2018.10.162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ferreira L, Moniz AC, Carneiro AS, Miranda AS, Fangueiro C, Fernandes D, Silva I, Palhinhas I, Lemos J, Antunes J, Leal M, Sampaio N, Faria S. The impact of glycemic variability on length of stay and mortality in diabetic patients admitted with community-acquired pneumonia or chronic obstructive pulmonary disease. Diabetes Metab Syndr 2019; 13:149-153. [PMID: 30641688 DOI: 10.1016/j.dsx.2018.08.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 08/27/2018] [Indexed: 01/07/2023]
Abstract
AIM To investigate the influence of glycemic variability (GV) on length of stay and in-hospital mortality in non-critical diabetic patients. METHODS A observation retrospective study was performed. Diabetic patients admitted between January and June 2016 with the diagnosis of community-acquire pneumonia (CAP) and/or acute exacerbation of chronic obstructive pulmonary disease (COPD) were enrolled and glycemic control (persistent hyperglycemia, hypoglycemia, mean glucose level (MGL) and respective standard deviation (SD) and coefficient of variation (CV)) were evaluated. Primary outcomes were length of stay and in-hospital mortality. RESULTS Data from 242 patients were analyzed. Fifty-eight percent of the patients were male, with a median age of 77 years (min-max, 29-98). Patients had on average 2.1 glucose readings-day and the MGL was 193.3 mg/dl (min-max, 84.3-436.6). Hypoglycemia was documented in 13.4% of the patients and 55.4% had persistent hyperglycemia. The median length of hospital stay was 10 days (min-max, 1-66) and in-hospital mortality was 7.4%. We found a significant higher in-hospital mortality in older patients, with history of cancer and with nosocomial infections. We did not find any correlation between MGL, SD, CV, hypoglycemia or persist hyperglycemia and in-hospital mortality. A longer length of stay was observed in patients with heavy alcohol consumption and nosocomial infections. The length of stay was negatively correlated with the mean glucose level (r2-0.147; p < 0.05) and positively correlated with the coefficient of variation (p 0.162; p < 0.05). CONCLUSION This study confirmed the negative impact of the glycemic variability in the outcomes of diabetic patients admitted with CAP or acute exacerbation of COPD.
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Correia LP, Almeida BD, Baracat EC, Silva I, Júnior JSJ, Bonduki C, Haidar MA. Efficacy and effects of transdermal hormone therapy in postmenopausal women. CLIN EXP OBSTET GYN 2018. [DOI: 10.12891/ceog4328.2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Aquino J, Parente J, Moreira J, Silva I. PNM-12 Double-blind Randomized Study on the Effect of Non-Hormonal Gel Application to the Genital Area of Women in the Menacme with Sexual Dysfunction. J Sex Med 2017. [DOI: 10.1016/j.jsxm.2017.10.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Vilhena E, Ribeiro JLP, Silva I, Pedro L, Meneses R, Cardoso H, da Silva AM, Mendonça D. Psychosocial Factors as Predictors of Adjustment to Life in Chronic Portuguese Patients. Eur J Public Health 2017. [DOI: 10.1093/eurpub/ckx189.241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Silva I, Rausch V, Peccerella T, Millonig G, Seitz H, Mueller S. S21-1HYPOXIA INDUCES HEPCIDIN IN THE LIVER: ROLE OF STAT3. Alcohol Alcohol 2017. [DOI: 10.1093/alcalc/agx075.79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Alperi A, Pascual I, Molina BD, Silva I, Lorca R, Hernández-Vaquero D, Avanzas P, Lambert JL, de la Tassa CM. Fever, Malaise, and Dyspnea in a Diabetic Heart Transplant Patient: A Case Report. Transplant Proc 2017; 49:1667-1671. [PMID: 28838461 DOI: 10.1016/j.transproceed.2017.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/10/2017] [Accepted: 04/27/2017] [Indexed: 10/19/2022]
Abstract
Patients with solid-organ transplants usually present at the emergency department with nonspecific symptoms. The physician should consider a great variety of syndromes and diseases, given the greater risk that solid-organ transplant patients carry because of immunosuppression and transplant-related conditions. Myocardial infarction caused by cardiac allograft vasculopathy must be always suspected and ruled out, even when initial symptoms do not orientate in that direction. We present a case that conjugates signs that can be present in different pathologies. It shows that fever is not always related to infection or rejection but could also appear in acute cardiac allograft vasculopathy. It emphasizes the need of a multi-disciplinary team led by a heart transplant specialist when dealing with this sort of clinical case.
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Singer D, Silva I, Mavris. Medicines Communications Using Digital Media: Findings from a Survey of Member Organisations of the European Medicines Agency’s Patients and Consumers and Health Professionals Working Parties (PCWP and HCPWP). Clin Ther 2017. [DOI: 10.1016/j.clinthera.2017.05.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Lugo L, Marcano A, Gomez-Polo J, Silva I, Gomez-Hospital J, Vivas D, De La Hera J, Tello-Montoliu A, Marin F, Cequier A, Roldan I, Ferreiro J. P3692Underuse of prasugrel and ticagrelor in patients with chronic kidney disease despite achieving a more effective platelet inhibition than clopidogrel. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx504.p3692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Monteiro D, Silva I, Egipto P, Magalhães A, Filipe R, Silva A, Rodrigues A, Costa J. Inhalation injury in a burn unit: a retrospective review of prognostic factors. ANNALS OF BURNS AND FIRE DISASTERS 2017; 30:121-125. [PMID: 29021724 PMCID: PMC5627549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 03/18/2017] [Indexed: 06/07/2023]
Abstract
Inhalation injury (InI) is known to seriously affect the prognosis of burn patients, as it is strongly associated with high morbidity and mortality. Despite major advances in the treatment of burn patients in the past years, advances in the treatment of smoke InI have been somewhat limited; mortality reduction mostly results from improvements in critical care. It is difficult to separate the contribution of InI from other mechanisms that also affect respiratory tract and lungs. The aim of this study was to compare patients with and without InI and to identify prognostic factors among patients with smoke InI. Patients with InI displayed higher total body surface area (TBSA) burned, higher incidence of pneumonia and acute respiratory distress syndrome (ARDS), a higher rate of positive blood cultures and a significantly higher death rate. We could conclude that older age, higher TBSA, ARDS and pneumonia were independent predictive factors for mortality in our global study population. Older age and higher TBSA were the only independent factors found to be predictive of mortality in patients with InI.
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Guillén-Gómez E, Dasilva I, Silva I, Arce Y, Facundo C, Ars E, Breda A, Ortiz A, Guirado L, Ballarín JA, Díaz-Encarnación MM. Early Macrophage Infiltration and Sustained Inflammation in Kidneys From Deceased Donors Are Associated With Long-Term Renal Function. Am J Transplant 2017; 17:733-743. [PMID: 27496082 DOI: 10.1111/ajt.13998] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 07/28/2016] [Accepted: 07/29/2016] [Indexed: 01/25/2023]
Abstract
Kidney transplants from living donors (LDs) have a better outcome than those from deceased donors (DDs). Different factors have been suggested to justify the different outcome. In this study, we analyzed the infiltration and phenotype of monocytes/macrophages and the expression of inflammatory and fibrotic markers in renal biopsy specimens from 94 kidney recipients (60 DDs and 34 LDs) at baseline and 4 months after transplantation. We evaluated their association with medium- and long-term renal function. At baseline, inflammatory gene expression was higher in DDs than in LDs. These results were confirmed by the high number of CD68-positive cells in DD kidneys, which correlated negatively with long-term renal function. Expression of the fibrotic markers vimentin, fibronectin, and α-smooth muscle actin was more elevated in biopsy specimens from DDs at 4 months than in those from LDs. Gene expression of inflammatory and fibrotic markers at 4 months and difference between 4 months and baseline correlated negatively with medium- and long-term renal function in DDs. Multivariate analysis point to transforming growth factor-β1 as the best predictor of long-term renal function in DDs. We conclude that early macrophage infiltration, sustained inflammation, and transforming growth factor-β1 expression, at least for the first 4 months, contribute significantly to the difference in DD and LD transplant outcome.
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Mourão M, Silva I, Almeida C, Neng N, Nogueira J. Application of polyurethane-based devices as sorption-desorption phases for microextraction analysis – The all-in-one microextraction concept. J Chromatogr A 2017; 1485:1-7. [DOI: 10.1016/j.chroma.2017.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/28/2016] [Accepted: 01/02/2017] [Indexed: 11/24/2022]
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Silva I, Cardemil C, Kashani H, Bazargani F, Tarnow P, Rasmusson L, Suska F. Quality of life in patients undergoing orthognathic surgery – A two-centered Swedish study. J Craniomaxillofac Surg 2016; 44:973-8. [DOI: 10.1016/j.jcms.2016.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/03/2016] [Accepted: 04/06/2016] [Indexed: 10/21/2022] Open
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Figueiredo A, Serafim P, Azzolini A, lo Turco E, Silva I, Forones N. P-008 Plasma lipidome of patients with advanced colorectal cancer. Ann Oncol 2016. [DOI: 10.1093/annonc/mdw199.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Saldanha do Carmo C, Nunes AN, Silva I, Maia C, Poejo J, Ferreira-Dias S, Nogueira I, Bronze R, Duarte CMM. Formulation of pea protein for increased satiety and improved foaming properties. RSC Adv 2016. [DOI: 10.1039/c5ra22452g] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pea protein was successfully encapsulated into a lipophilic carrier through PGSS®. HPT-scCO2of pea protein has enabled higher foam stability.
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Dall Cortivo P, Bretas A, Silva I, Braccini J, McManus C. Curvas de crescimento morfológico para suínos localmente adaptados no Brasil. ARCHIVOS DE ZOOTECNIA 2015. [DOI: 10.21071/az.v64i248.429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
No presente estudo objetivou-se determinar curvas de crescimento para quatro raças de suínos naturalizados do Brasil (Moura, Piau, Nilo e Monteiro) através de ajustes não lineares. Foram coletados dados de 13 medidas morfológicas de 220 exemplares de ambos os sexos entre os 30 dias de vida até a idade adulta. As curvas foram ajustadas usando regressão não linear, pelas equações de Gompertz, Weibull, Logística, Brody e Richards. A melhor função foi selecionada pelo maior R² e menor erro quadrático médio, sendo a função de Weibull a mais apropriada para todas as raças e sexos. No geral, as fêmeas de todas as raças atingiram as medidas adultas com mais precocidade, porém os machos cresceram mais do que as fêmeas. O crescimento da raça Moura é o que mais se assemelha ao crescimento das raças industriais, isso pode estar relacionado ao fato de grande parte dos exemplares serem criados em sistemas de engorda. Por outro lado, a raça Monteiro foi a que apresentou um crescimento mais tardio. Conclui-se que as raças de suínos naturalizados brasileiros possuem crescimento diferenciado, que está relacionado com a origem genética da raça e adaptação ao ambiente.
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Castro Afonso A, Silva I. ORAL HEALTH-RELATED QUALITY OF LIFE AND ASSOCIATED VARIABLES: INTEGRATIVE REVIEW. PSICOLOGIA, SAÚDE & DOENÇAS 2015. [DOI: 10.15309/15psd160304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Silva-Ramos M, Silva I, Faria M, Magalhães-Cardoso MT, Correia J, Ferreirinha F, Correia-de-Sá P. Impairment of ATP hydrolysis decreases adenosine A1 receptor tonus favoring cholinergic nerve hyperactivity in the obstructed human urinary bladder. Purinergic Signal 2015; 11:595-606. [PMID: 26521170 DOI: 10.1007/s11302-015-9478-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022] Open
Abstract
This study was designed to investigate whether reduced adenosine formation linked to deficits in extracellular ATP hydrolysis by NTPDases contributes to detrusor neuromodulatory changes associated with bladder outlet obstruction in men with benign prostatic hyperplasia (BPH). The kinetics of ATP catabolism and adenosine formation as well as the role of P1 receptor agonists on muscle tension and nerve-evoked [(3)H]ACh release were evaluated in mucosal-denuded detrusor strips from BPH patients (n = 31) and control organ donors (n = 23). The neurogenic release of ATP and [(3)H]ACh was higher (P < 0.05) in detrusor strips from BPH patients. The extracellular hydrolysis of ATP and, subsequent, adenosine formation was slower (t (1/2) 73 vs. 36 min, P < 0.05) in BPH detrusor strips. The A(1) receptor-mediated inhibition of evoked [(3)H]ACh release by adenosine (100 μM), NECA (1 μM), and R-PIA (0.3 μM) was enhanced in BPH bladders. Relaxation of detrusor contractions induced by acetylcholine required 30-fold higher concentrations of adenosine. Despite VAChT-positive cholinergic nerves exhibiting higher A(1) immunoreactivity in BPH bladders, the endogenous adenosine tonus revealed by adenosine deaminase is missing. Restoration of A1 inhibition was achieved by favoring (1) ATP hydrolysis with apyrase (2 U mL(-1)) or (2) extracellular adenosine accumulation with dipyridamole or EHNA, as these drugs inhibit adenosine uptake and deamination, respectively. In conclusion, reduced ATP hydrolysis leads to deficient adenosine formation and A(1) receptor-mediated inhibition of cholinergic nerve activity in the obstructed human bladder. Thus, we propose that pharmacological manipulation of endogenous adenosine levels and/or A(1) receptor activation might be useful to control bladder overactivity in BPH patients.
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Costa D, Barata P, Silva I, Cardoso C, Moita F, Cunha M, Nunes A, Guerreiro F, Miranda N. 3225 Hyperbaric oxygen therapy for the management of late-onset haemorrhagic cystitis after allogeneic bone marrow transplantation - Experience of a Hyperbaric Medicine Centre. Eur J Cancer 2015. [DOI: 10.1016/s0959-8049(16)31802-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ramírez I, Paiva VH, Fagundes I, Menezes D, Silva I, Ceia FR, Phillips RA, Ramos JA, Garthe S. Conservation implications of consistent foraging and trophic ecology in a rare petrel species. Anim Conserv 2015. [DOI: 10.1111/acv.12227] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Branco J, Rodrigues A, Gouveia N, Pereira L, Eusébio M, Ramiro S, Machado P, Mourão A, Silva I, Laires P, Sepriano A, Araújo F, Gonçalves S, Coelho P, Tavares V, Cerol J, Mendes J, Carmona L, Canhão H. OP0052 Prevalence and Physical and Mental Health Patterns of Rheumatic and Musculoskeletal Diseases in Portugal: Results from Epireumapt, A National Health Survey. Ann Rheum Dis 2015. [DOI: 10.1136/annrheumdis-2015-eular.3854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Reis I, Alves J, Silva I, Ormonde T, Ferreira C, Moita J. Characterizing a population of smokers: An observational, transversal, non-randomized pilot study based on smoking history and spirometry changes. REVISTA PORTUGUESA DE PNEUMOLOGIA 2015; 21:169-70. [PMID: 25926259 DOI: 10.1016/j.rppnen.2015.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 01/26/2015] [Accepted: 02/07/2015] [Indexed: 11/28/2022] Open
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Sala P, Machado N, Belarmino G, Ishida R, Guarda I, Giannella‐Neto D, Santo MA, Moura E, Sakai P, Silva I, Ye J, Heymsfield S, Waitzberg D. Reduced Transcobalamin I Gene Expression Following Roux‐en‐Y Gastric Bypass Surgery Can Contribute to B12 Deficiency. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.lb350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Silva I, Almeida J, Vasconcelos C. A PRISMA-driven systematic review for predictive risk factors of digital ulcers in systemic sclerosis patients. Autoimmun Rev 2014; 14:140-52. [PMID: 25449678 DOI: 10.1016/j.autrev.2014.10.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 10/04/2014] [Indexed: 01/20/2023]
Abstract
Vasculopathy has a major role in the pathogenesis and tissue injury in systemic sclerosis (SSc). Raynaud's phenomenon (RP) is frequently the first clinical manifestation of SSc preceding by years other clinical manifestations. RP in SSc patients is frequent, often very severe and long lasting. The repeated bouts of RP lead to prolonged digital ischemia that may progress to digital ulceration or in extreme to critical digital ischemia with gangrene. Digital ulcers (DU) are a true burden for all patients. They are very painful, with a long and slow healing course, have high risk of infection and are extremely disabling. In adults, up to 40-50% of patients will experience at least one DU in the course of the disease and of these 31-71% will have recurrent ulcers. In order to try to identify predictive risk factors for DU in SSc patients, an extensive literature review was conducted, according to the guidelines proposed at the PRISMA statement. MEDLINE database (PubMed) and Thomson Reuters Web of Knowledge platform were searched for articles published in peer-reviewed journals since 1990 with the last search run on June 2014 and published in English language. The keyword search terms included: digital ulcer/s, systemic sclerosis, scleroderma, digital scars, ischemic complications, autoantibodies, biomarkers, endothelium dysfunction, endothelin-1, vascular endothelial growth factor (VEGF), endostatin, ADMA, endoglin, angiostatin, and capillaroscopy. The following criteria were included: (1) cohorts of SSc patients including patients with DU, (2) endothelium dysfunction and angiogenesis biomarkers compared with a healthy control group, (3) autoantibodies, capillary morphology and distribution, endothelium dysfunction and angiogenesis biomarkers compared between patients with and without digital ulcers, (4) detailed description of the statistical methods used to conclude for predictive factors, and (5) English language. Our search provided a total of 376 citations. Of these, 297 studies were discarded for not meeting the criteria proposed.
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Oliveira L, Costa AC, Noronha-Matos JB, Silva I, Cavalcante WLG, Timóteo MA, Corrado AP, Dal Belo CA, Ambiel CR, Alves-do-Prado W, Correia-de-Sá P. Amplification of neuromuscular transmission by methylprednisolone involves activation of presynaptic facilitatory adenosine A2A receptors and redistribution of synaptic vesicles. Neuropharmacology 2014; 89:64-76. [PMID: 25220030 DOI: 10.1016/j.neuropharm.2014.09.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 08/19/2014] [Accepted: 09/02/2014] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying improvement of neuromuscular transmission deficits by glucocorticoids are still a matter of debate despite these compounds have been used for decades in the treatment of autoimmune myasthenic syndromes. Besides their immunosuppressive action, corticosteroids may directly facilitate transmitter release during high-frequency motor nerve activity. This effect coincides with the predominant adenosine A2A receptor tonus, which coordinates the interplay with other receptors (e.g. muscarinic) on motor nerve endings to sustain acetylcholine (ACh) release that is required to overcome tetanic neuromuscular depression in myasthenics. Using myographic recordings, measurements of evoked [(3)H]ACh release and real-time video microscopy with the FM4-64 fluorescent dye, results show that tonic activation of facilitatory A2A receptors by endogenous adenosine accumulated during 50 Hz bursts delivered to the rat phrenic nerve is essential for methylprednisolone (0.3 mM)-induced transmitter release facilitation, because its effect was prevented by the A2A receptor antagonist, ZM 241385 (10 nM). Concurrent activation of the positive feedback loop operated by pirenzepine-sensitive muscarinic M1 autoreceptors may also play a role, whereas the corticosteroid action is restrained by the activation of co-expressed inhibitory M2 and A1 receptors blocked by methoctramine (0.1 μM) and DPCPX (2.5 nM), respectively. Inhibition of FM4-64 loading (endocytosis) by methylprednisolone following a brief tetanic stimulus (50 Hz for 5 s) suggests that it may negatively modulate synaptic vesicle turnover, thus increasing the release probability of newly recycled vesicles. Interestingly, bulk endocytosis was rehabilitated when methylprednisolone was co-applied with ZM241385. Data suggest that amplification of neuromuscular transmission by methylprednisolone may involve activation of presynaptic facilitatory adenosine A2A receptors by endogenous adenosine leading to synaptic vesicle redistribution.
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