257 research outputs found
Testing a novel device for accurate ultrasound delivery during crystalline lens phacoemulsification surgery
Purpose: To assess whether the use of a patented, novel feedback device intended to accurately control phacoemulsification tip elongation is effective under varying machine settings and material resistance. Methods: Sculpt mode phaco (550-mm Hg Venturi pump; elongations, 35 and 70 ÎŒm) and quadrant settings (550-mm Hg Venturi pump; elongations, 15, 30, and 60 ÎŒm) were used in agar gel of incremental density (1%, 2%, 3%, and 6% in demineralized water). Dispersed lens fragments were also simulated with 6% agar gel spherules (2â5 mm in diameter; 550-mm Hg vacuum, and 60-ÎŒm elongation). Actual phaco tip elongation was measured on voltage readings from the piezoelectric crystals and compared to nominal elongation with feedback control off and on. Results: Mismatch between nominal and actual elongation when feedback control was off in sculpt mode varied between â13.51 ÎŒm and â23.07 ÎŒm of nominal elongation; in quadrant mode, mismatch varied between â2.79 ÎŒm and â20.41 ÎŒm. When the feedback control system was switched on, mismatch varied between â0.02 ÎŒm and +0.43 ÎŒm (P < 0.001 for all matchings). When the feedback system was off, the elongation mismatch among the 1%, 3%, and 6% agar was also statistically significant (P < 0.001). Elongation was 44.72 ± 4.16 ÎŒm with feedback control off and 60.02 ± 1.63 ÎŒm with it on (nominal elongation 60 ÎŒm; P < 0.001) when emulsifying agar 6% gel fragments. Dispersion of elongation data was also significantly wider when feedback control was turned off. Conclusions: A novel feedback control system effectively controls elongation accuracy regardless of the resistance offered by incremental agar gel concentrations. Translational Relevance: Implementing feedback control in phaco handpieces dramatically improves surgical accuracy. The translational value of this research relies on its immediate applicability to routine cataract surgery, resulting in a more appropriate use of ultrasound energy
Conformational changes produced by ATP binding to the plasma membrane calcium pump
The aim of this work was to study the plasma membrane calcium pump (PMCA) reaction cycle by characterizing conformational changes associated with calcium, ATP, and vanadate binding to purified PMCA. This was accomplished by studying the exposure of PMCA to surrounding phospholipids by measuring the incorporation of the photoactivatable phosphatidylcholine analog 1-O-hexadecanoyl-2-O-[9-[[[2-[125I]iodo-4-(trifluoromethyl-3H-diazirin-3-yl)benzyl]oxy]carbonyl]nonanoyl]-sn-glycero-3-phosphocholine to the protein. ATP could bind to the different vanadate-bound states of the enzyme either in the presence or in the absence of Ca2+ with high apparent affinity. Conformational movements of the ATP binding domain were determined using the fluorescent analog 2âČ(3âČ)-O-(2,4,6-trinitrophenyl)adenosine 5âČ-triphosphate. To assess the conformational behavior of the Ca2+ binding domain, we also studied the occlusion of Ca2+, both in the presence and in the absence of ATP and with or without vanadate. Results show the existence of occluded species in the presence of vanadate and/or ATP. This allowed the development of a model that describes the transport of Ca2+ and its relation with ATP hydrolysis. This is the first approach that uses a conformational study to describe the PMCA P-type ATPase reaction cycle, adding important features to the classical E1-E2 model devised using kinetics methodology only.Fil: Mangialavori, Irene C.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; ArgentinaFil: Ferreira Gomes, Mariela S.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; ArgentinaFil: Saffioti, Nicolas A.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; ArgentinaFil: Gonzalez-Lebrero, Rodolfo Martin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; ArgentinaFil: Rossi, Rolando Carlos. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; ArgentinaFil: Rossi, Juan Pablo Francisco. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂmica y FisicoquĂmica BiolĂłgicas; Argentin
Primary Prophylaxis for Gastrointestinal Bleeding in Children With Biliary Atresia and Portal Hypertension Candidates for Liver Transplantation: A Single-Center Experience
Background. Cirrhosis for biliary atresia (BA) is associated with risk of gastrointestinal bleeding (GB) from gastroesophageal varices due to portal hypertension. Primary prophylaxis of GB is controversial in children who are candidates for liver transplantation (LT). The aim of the study was to define the management of gastroesophageal varices and to identify the benefit of primary prophylaxis for GB in BA children waiting for LT.Methods. A retrospective single-center study including all BA children listed for LT in 2008-2016. Clinical, endoscopical, and biochemical data were analyzed.Results. Of 82 children, 50 (61%) did not receive primary prophylaxis and did not present any episode of bleeding, 16 (19.5%) underwent primary prophylaxis, and 16 (19.5%) presented spontaneous GB and received secondary prophylaxis. Children without primary prophylaxis and GB were younger than patients with primary prophylaxis and those with GB (7.7 years [range, 4.1-37.9 years] vs 11.2 years [range, 5.1-43 years]; P = .03 vs 10.7 years [range, 6.9-39.9 years], respectively; P = .004). Seventy-five percent of GB occurred in children older than 8 months. Fifteen (93.8%) children with GB presented esophageal varices (grade III = 10 [62.5%]) and 10 (62.5%) required endoscopic treatments, consisting mainly of sclerotherapy. Median time to LT was similar for children with or without bleeding (2 months [range, 0-17.7 months] vs 2.2 months [0-17.9 months], respectively; P = .89). After 45.5 months (range, 13.7-105.5 months) of follow-up, the overall patient survival was 97.6%. At the intention-to-treat analysis, the survival rate was 100% for patients without bleeding episode and 87.5% for children with GB (P = .16).Conclusions. Despite the risk of GB being not clinically predictable in children with BA waiting for LT, our experience suggests that primary prophylaxis of GB might be unnecessary in children younger than 6 months, while it should be considered in older children. Thus, the occurrence of GB does not delay the timing of transplantation
Life-saving vascular access after combined liver and kidney transplantation: A challenging access to the right atrium
Exhaustion of vascular accesses is a major complication in patients undergoing hemodialysis, especially in pediatric setting. We report the case of a boy treated for loss of hemodialysis access after a combined liver-kidney transplantation and transient renal dysfunction. An interventional dilatation of calcific superior vena cava allowed to insert a stable central venous line for dialysis until full graft recovery. Careful management of central lines allows to spare the main vessels and reduces the need for unusual accesses
Defective spleen function in autoimmune gastrointestinal disorders
Defective spleen function increases susceptibility to bacterial infections which can be prevented by vaccine prophylaxis. Splenic hypofunction can be found in a number of autoimmune disorders; however, no data are available regarding autoimmune atrophic gastritis (AAG), autoimmune enteropathy (AIE) and autoimmune liver disease (AILD). Peripheral blood samples from patients with AAG (nâ=â40), AIE (nâ=â3) and AILD (nâ=â40) were collected. Patients affected by autoimmune disorders already known to be associated with splenic hypofunction, i.e. coeliac disease (CD) and ulcerative colitis (UC), were included as disease controls, while splenectomised patients and healthy subjects were evaluated as positive and negative controls, respectively. Counting of erythrocytes with membrane abnormalities, i.e. pitted red cells, was used as an indicator of spleen function (normal upper limit 4%). Defective splenic function was observed in 22 of the 40 patients with AAG (55.0%), in two of the three patients with AIE (66.6%) and in 35 of the 40 patients with AILD (87.5%). As expected, in untreated CD, refractory CD and UC there was a high prevalence of hyposplenism (43.7%, 88.2% and 54.4%, respectively). Due to the high prevalence of splenic hypofunction, patients with AAG, AILD and AIE should undergo pitted red cell evaluation and, if hyposplenic, they should be candidate to vaccine prophylaxis against encapsulated bacteria
Serological markers of extracellular matrix remodeling predict transplantâfree survival in primary sclerosing cholangitis
BACKGROUND: Primary sclerosing cholangitis is a progressive liver disease with a remarkably variable course. Biomarkers of disease activity or prognostic models predicting outcome at an individual level are currently not established. AIM: To evaluate the prognostic utility of four biomarkers of basement membrane and interstitial extracellular matrix remodeling in patients with primary sclerosing cholangitis. METHODS: Serum samples were available from 138 largeâduct primary sclerosing cholangitis patients (of which 102 [74%] with IBD) recruited 2008â2012 and 52 ulcerative colitis patients (controls). The median followâup time was 2.2 (range 0â4.3) years. Specific biomarkers of type III and V collagen formation (PROâC3 and PROâC5, respectively) and type III and IV collagen degradation (C3M and C4M, respectively) were assessed. The Enhanced Liver Fibrosis test, including procollagen type III Nâterminal peptide, tissue inhibitor of metalloproteinaseâ1 and hyaluronic acid was assessed for comparison. RESULTS: All markers were elevated in primary sclerosing cholangitis compared to ulcerative colitis patients (P < 0.001). PROâC3 showed the largest difference between the two groups with a threefold increase in primary sclerosing cholangitis compared to ulcerative colitis patients. Patients with high baseline serum levels of all markers, except C3M, had shorter survival compared to patients with low baseline serum levels (P < 0.001). Combining PROâC3 and PROâC5 the odds ratio for predicting transplantâfree survival was 47 compared to the Enhanced Liver Fibrosis test's odds ratio of 11. CONCLUSIONS: Extracellular matrix remodeling is elevated in primary sclerosing cholangitis patients compared to ulcerative colitis patients. Furthermore, the interstitial matrix marker PROâC3 was identified as a potent prognostic marker and an independent predictor of transplantâfree survival in primary sclerosing cholangitis
A disease-associated gene desert directs macrophage inflammation through ETS2
Increasing rates of autoimmune and inflammatory disease present a burgeoning threat to human health1. This is compounded by the limited efficacy of available treatments1 and high failure rates during drug development2, highlighting an urgent need to better understand disease mechanisms. Here we show how functional genomics could address this challenge. By investigating an intergenic haplotype on chr21q22âwhich has been independently linked to inflammatory bowel disease, ankylosing spondylitis, primary sclerosing cholangitis and Takayasuâs arteritis3â6âwe identify that the causal gene, ETS2, is a central regulator of human inflammatory macrophages and delineate the shared disease mechanism that amplifies ETS2 expression. Genes regulated by ETS2 were prominently expressed in diseased tissues and more enriched for inflammatory bowel disease GWAS hits than most previously described pathways. Overexpressing ETS2 in resting macrophages reproduced the inflammatory state observed in chr21q22-associated diseases, with upregulation of multiple drug targets, including TNF and IL-23. Using a database of cellular signatures7, we identified drugs that might modulate this pathway and validated the potent anti-inflammatory activity of one class of small molecules in vitro and ex vivo. Together, this illustrates the power of functional genomics, applied directly in primary human cells, to identify immune-mediated disease mechanisms and potential therapeutic opportunities
Use of colistin in adult patients: A cross-sectional study
Objectives: The aim of this study was to assess colistin use in a country endemic for multidrug-resistant Gram-negative bacteria (MDR-GNB). Methods: Colistin prescription patterns were evaluated in 22 Italian centres. Factors associated with use of colistin in combination with other anti-MDR-GNB agents were also assessed. Results: A total of 221 adults receiving colistin were included in the study. Their median age was 64 years (interquartile range 52\u201373 years) and 134 (61%) were male. Colistin was mostly administered intravenously (203/221; 92%) and mainly for targeted therapy (168/221; 76%). The most frequent indications for colistin therapy were bloodstream infection and lower respiratory tract infection. Intravenous colistin was administered in combination with at least another anti-MDR-GNB agent in 80% of cases (163/203). A loading dose of 9 MU of colistimethate was administered in 79% of patients receiving i.v. colistin and adequate maintenance doses in 85%. In multivariable analysis, empirical therapy [odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.24\u20138.53;P = 0.017] and targeted therapy for carbapenem-resistant Enterobacterales infection (OR = 4.76, 95% CI 1.69\u201313.43; P = 0.003) were associated with use of colistin in combination with other agents, whilst chronic renal failure (OR = 0.39, 95% CI 0.17\u20130.88; P = 0.024) was associated with use of colistin monotherapy. Conclusion: Colistin remains an important option for severe MDR-GNB infections when other treatments are not available. Despite inherent difficulties in optimising its use owing to peculiar pharmacokinetic/pharmacodynamic characteristics, colistin was mostly used appropriately in a country endemic for MDR-GNB
Um estudo bibliomĂ©trico sobre a violĂȘncia de gĂȘnero
Resumo A violĂȘncia de gĂȘnero, apesar de global, Ă© socialmente invisĂvel, sendo urgente o avanço de produção cientĂfica sobre esse tema. Um estudo bibliomĂ©trico majora a demanda de debates ao demonstrar que as pesquisas abrangeram poucos paĂses, ignoraram as consequĂȘncias dos danos e ainda sĂŁo, apesar de sua ampliação, incipientes. Este artigo objetivou descrever o panorama da produção cientĂfica sobre violĂȘncia de gĂȘnero, procurando tecer uma anĂĄlise crĂtica diante da magnitude da demanda. Buscaram-se artigos em inglĂȘs, pelos descritores gender e violence, na base de dados Web of Science, de 1982 a 2012, excluindo-se os textos de ĂĄreas especĂficas, que tratavam da violĂȘncia geral ou adotaram "gĂȘnero" em substituição a sexo, restando 450 artigos. A bibliometria ratificou que as mulheres encontram-se em mais situaçÔes de violĂȘncias, apesar da referĂȘncia a crianças e adolescentes, homossexuais e homens. A produtividade das pesquisas em diversas ĂĄreas do conhecimento Ă© crescente, revelando sua natureza multidisciplinar. Apenas 26 paĂses sediaram estudos, nĂșmero reduzido diante da amplitude do problema. A maioria dos estudos nĂŁo abordou as consequĂȘncias da violĂȘncia de gĂȘnero, demonstrando uma importante lacuna na produção cientĂfica. Esta pesquisa evidenciou pontos pouco explorados pela produção cientĂfica, servindo de orientação para futuros estudos
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