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Evaluation of right and left ventricular strain on hemodialysis patients before and after a dialysis session with three dimensional speckle tracking echocardiography and comparison of this assessment with hemodialysis parameters
No full textHemodiyaliz sırasında akut değişimlerin miyokarda etkileri henüz net bilinmemektedir. Bu akut değişimlerin, miyokardın gerilmesini ve deformasyonunu gösteren strain analizleri ile anlaşılması mümkündür. Strain, miyokard deformasyonunun orijinal boyutuna göre değişim ölçüsüdür, miyokardın gerilmesini gösterir ve yüzde olarak ifade edilir. Hemodiyaliz (HD) tedavisi alan hastalarda, morbidite ve mortalitenin ana nedenleri olan kalp yetmezliği ve koroner arter hastalığı riski yüksektir. Kardiyak yapı ve fonksiyondaki anormalliklerin erken teşhisi, zamanında ve uygun kardiyak müdahaleler için kritik olabilir. Yeni geliştirilen üç boyutlu benek takibi ekokardiyografi (3BBTE) ile ventriküler segmentlerin hareketleri aynı anda üç uzamsal yönde değerlendirilebilir. Gereç ve Yöntem: Kasım 2017 - Mayıs 2019 tarihleri arasında Ankara Üniversitesi Tıp Fakültesi İbni Sina Hastanesi'nde bilinen kardiyovasküler hastalığı bulunmayan, HD tedavisi alan 38 hasta 3BBTE kullanılarak HD öncesi ve hemen sonrası değerlendirildi. Demografik veriler, komorbiditeler, renal replasman tedavisi özellikleri ve laboratuvar test sonuçları hakkında veri toplandı. Her iki ventrikül için diyastol sonu hacim indeksi (EDVi), sistol sonu hacim indeksi (ESVi), atım hacmi indeksi (SVi), ejeksiyon fraksiyonu (EF), sol ventrikül için ayrıca kütle indeksi (SoVMi) değerlendirildi ve 3B benek takibi analizleri kullanılarak sol ventrikül (SoV) global boyuna (GLS), global çevresel (GCS), global alan (GAS) ve global radyal (GRS) strain ve sağ ventrikül (SaV) septum ve serbest duvar boyuna strain (LS) ve fraksiyonel alan değişimi (FAC) hesaplandı. Bulgular: Hastaların ortalama yaşı 52,8±13,6 yıl ve 20 hasta (%52,6) erkekti. Ortalama diyaliz tedavi zamanı 56,5 aydı ve hastalar ortalama Kt/V 1,66±0,25 ile yeterli diyaliz tedavisi aldı. Hastaların her iki ventrikül hacim ölçümleri HD sonrası belirgin azaldı. Hastaların sol ventrikül strain değerlerinin hemodiyalizin hemen öncesinde ve sonrasında sırasıyla "GLS: -14.2±5.2, -11.1±4.6 (p<0,001); GCS: -14.8±4.2, -12.4±5.2 (p:0,009); GRS:41.5±16, 33.3±16.5 (p:0,003); AREA:-24.7±7.2, -20.1±7.6 (p:0,001)" belirgin değiştiği gözlendi. Sağ ventrikül boyuna strain değerleri de HD seansı öncesi ve sonrasında sırasıyla "LS septum:-10.5±4.9, -10.1±4.2 (p:0,675); LS Freewall: -15.2±5.1, -13.1±5,5 (p:0,127); FAC: 31.5±8.8, 29.2±7.7 (p:0.285)" olarak gözlendi fakat anlamlı değişim saptanmadı. SoV strain analizleri diyaliz seansları sırasında kan basıncı değişkenliği ile pozitif korelasyon gösterdi (p <0.001). Beta bloker (BB) veya kalsiyum kanal bloker (KKB) tedavisi alan hastalarda, bu ajanları kullanmayan hastalarla karşılaştırıldığında SoV miyokard fonksiyonları HD'den daha iyi korundu (BB p <0.001 ve CCB p <0.01). Sonuç: HD sırasında sol ventrikül miyokardiyal strain belirgin bozulmakta fakat sağ ventrikül miyokardiyal strain etkilenmemektedir. Ayrıca bu çalışma, hemodiyalizin sağ ventrikül üzerine etkilerini 3BBTE ile değerlendiren ilk çalışmadır. Kronik HD hastalarında strain değerlendirmesi, daha iyi vasküler risk sınıflandırmasına katkıda bulunabilir.The effects of acute changes during hemodialysis on the myocardium are not yet known. It is possible to understand the strain analysis that shows myocardial distension and deformation. Strain is a measure of change in myocardial deformation relative to its original size, indicating the distension of the myocardium and expressed as a percentage. Patients on maintenance hemodialysis (HD) have a high prevalence of heart failure and coronary artery disease, which are the main causes of morbidity and mortality. Early detection of abnormalities in cardiac structure and function may be critical for timely and appropriate cardiac interventions. The newly-developed three dimensional speckle tracking echocardiography (3DSTE) has the potential to assess the movements of ventricular segments in three spatial directions simultaneously. Methods: Thirthy-eight patients on maintenance HD without any cardiovascular diseases at Ankara University School of Medicine Ibni Sina Hospital between November 2017 and May 2019 were examined just before and immediately after HD using 3DSTE. Data on demographics, comorbidities, renal replacement treatment characteristics and laboratory test results were collected. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF) of both ventricules, left ventricule mass index (LVMi) were evaluated and 3D speckle tracking analysis was performed to calculate left ventricule(LV) global longitudinal (GLS), circumferential (GCS), area (GAS) and radial (GRS) peak systolic strain and right ventricule (RV) septum and freewall longitudinal strain (LS) and fractional area change (FAC). Results: In our study group, patients were aged 52,8 ± 13,6 years and 52,6 % of them were male. Mean dialysis vintage time was 56 months and patients were on adequate dialysis treatment with mean Kt/V 1,66±0,25. Volume measurements of both ventricules were significantly lower after HD. The left ventricular strain values of the patients were markedly change before and after hemodialysis, respectively "GLS: -14.2 ± 5.2, -11.1 ± 4.6 (p <0.001); GCS: -14.8 ± 4.2, -12.4 ± 5.2 (p: 0.009); GRS: 41.5 ± 16, 33.3 ± 16.5 (p: 0.003); AREA: -24.7 ± 7.2, -20.1 ± 7.6 (p: 0.001)". No improvement was seen in RV strain values before and after HD, respectively "LS septum: -10.5±4.9, -10.1±4.2 (p:0,675), LS freewall: -15.2±5.1, -13.1±5,5 (p:0,127), FAC: 31,5±8,8, 29,2±7,7 (p:0,285)". LV strain analysis were positively correlated with blood pressure variability during dialysis sessions (p<0.001). LV myocardial functions were preserved better after HD in patients on beta-blocker (BB) or calcium channel blocker (CCB) therapy compared with patients who don't use these agents (BB p<0.001 and CCB p<0.01 for all LV strain values). Conclusion: HD treatment results in improvement in all LV strain directions but not in RV. This is the first study that evaluated the effects of HD on RV using 3DSTE. Strain assessment in maintenance HD patients may contribute to better vascular risk stratification
Factors determining arterial stiffness in chronic hemodialysis patients and their relation with sclerostin
No full textGiriş: Arteryel sertlik, kronik böbrek hastalığının (KBH) tüm evrelerinde kardiyovasküler olay ve mortalitede önemli bir risk faktörüdür. Yakın zamanlı çalışmalar bir Wnt inhibitörü olan sclerostinin KBH'de vasküler/valvüler kalsifikasyon ve düşük döngülü kemik hastalığı ile ilişkisini göstermiştir. Bu çalışmada kronik hemodiyaliz (HD) hastalarında arteryel sertliği belirleyen faktörler ve sclerostin ile ilişkilerinin değerlendirilmesi amaçlanmıştır. Metod: Bu prospektif çalışmaya Ankara Üniversitesi Tıp Fakültesi Nefroloji Bilim Dalı Hemodiyaliz merkezinde haftada 3 gün ve en az 6 aydır hemodiyaliz uygulanan 73 hasta ve 40 sağlıklı gönüllü kontrol grubu olarak alındı. Kontrol grubunda sclerostin ve hastalarda ise sclerostin ve karotid-femoral nabız dalga hızı (NDH) ölçümü yapıldı. Demografik veriler, laboratuvar verileri ve hastalara ait medikasyonlar kaydedildi. Bulgular: 35 kadın ve 38 erkekten oluşan HD hasta grubumuzun yaş ortalaması 55±15'ti. NDH ortalaması 9.2±2.7m/sn (kadınlarda 8.4 m/sn ve erkeklerde 9 m/sn, p:0.145). Hasta grubunda sclerostin, kontrol grubuna göre belirgin yüksek saptandı (327±207 pg/mL ve 141±88 pg/mL, p<0.001 ). Hasta grubunda cinsiyetler arası sclerostin değerlerinde anlamlı farklılık saptandı (kadınlarda 235 pg/mL ve erkeklerde 319 pg/mL, p:0.007). Tek değişkenli korelasyon analizinde NDH'nin yaş, DM, periferik, aort ve HD giriş sistolik arter basıncı, vücut kitle indeksi (VKİ), sclerostin, total kolesterol ve LDL ile pozitif; Kt/V, cinacalcet ve D vitamini kullanımıyla ise negatif korelasyon gösterdiği saptandı. Çoklu değişkenli regresyon analizinde ise NDH; yaş (β:0.068, p:0.003), DM (β:1.440, p:0.038) ve HD giriş sistolik arter basıncı (β:0.058, p:0.001) ile pozitif korelasyon gösterdi. Sclerostin için tek değişkenli korelasyon analizinde yaş, erkek cinsiyet, ASKH, statin kullanımı, VKİ ve NDH ile pozitif; ALP, PTH, Kt/V, cinacalcet ve D vitamini kullanımıyla ise negatif korelasyon gösterdiği saptandı. Çoklu değişkenli regresyon analizinde sclerostinin, erkek cinsiyet (β:174.82, p<0.001) ve statin kullanımı (β:168.96, p:0.05) ile pozitif; PTH (β:-0.282, p<0.001) ile negatif korelasyon gösterdiği saptandı. Sonuç: NDH ile sclerostin tek değişkenli korelasyon analizinde pozitif korelasyon gösterirken; çoklu değişkenli regresyon analizinde NDH ile sclerostin arasında ilişki saptanmamıştır. Hastaların seyrindeki sclerostin değişimlerinin, NDH değişimlerini predikte edip etmediğine dair daha geniş çalışmalara ihtiyaç bulunmaktadırIntroduction: Arterial stiffness is an important risk factor for cardiovascular events and mortality in all stages of chronic kidney disease (CKD). Recent studies have demonstrated that sclerostin, which is a Wnt inhibitor, is associated with vascular/valvular calcification in CKD and low cycle bone diseases. The aim of the present study was to evaluate the factors determining arterial stiffness in chronic hemodialysis (HD) patients and their relation with sclerostin. Method: 73 patients undergoing hemodialysis three times weekly for at least 6 months in hemodialysis center of nephroology department of Ankara University Medical School and 40 healthy volunteers as control group were included in this prospective study. In the control group sclerostin and in patients sclerostin and carotid-femoral pulse wave velocity (PWV) was measured. Demographic data, laboratory data, and medications of patients were recorded. Results: In HD patient group including 35 female and 38 male cases, mean age was 55±15. Mean pulse wave velocity was 9.2±2.7m/sec (in females 8.4 m/sec and in males 9 m/sec, p:0.145). In the patient groups, sclerostin level was found to be significantly higher than control group (327±207 pg/mL and 141±88 pg/mL respectively , p<0.001 ). In the patient groups, significant difference was found between genders in terms of sclerostin values (in females 235 pg/mL and in males 319 pg/mL, p:0.007). In single variable correlation analysis, it was established that PWV had positive correlation with age, DM, peripheral, aorta and HD onset systolic artery pressure, body mass index (BMI), sclerostin, total cholesterol and LDL cholesterol and negative correlation with Kt/V, cinacalcet and D vitamin use. In multi variable regression analysis, PWV has positive correlation with age (β:0.068, p:0.003), DM (β:1.440, p:0.038) and HD onset systolic artery pressure(β:0.058, p:0.001). In single variable correlation analysis, sclerostin had positive correlation with age, male sex, atherosclerotic cardiovascular disease, statin use, BMI and PWV and negative correlation with ALP, PTH, Kt/V, cinacalcet and D vitamin use. In multi variable regression analysis, sclerostin had positive correlation with male sex (β:174.82, p<0.001) and statin use (β:168.96, p:0.05) and negative correlation with PTH (β:-0.282, p<0.001) . Conclusion: While PWV and sclerostin had positive correlation in single variable correlation analysis, they had no correlation in multi variable regression analysis. Further studies with larger series are requiered in order to determine whether changes in sclerostin levels during the course of disease predict alterations in PWV
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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