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The Study of Dyslipidemia and the Cardiac Electromechanical Dysfunction
No full text許多動物實驗及人類研究結果顯示出,高膽固醇血症可以經由非動脈硬化的病生理機制
來增加心肌缺氧時的損害,例如改變心肌細胞膜上的鈉或鈣離子孔道,影響血小板的活性等
等。通常冠狀動脈粥狀硬化的過程需要數年的時間,而血脂異常所造成的心肌細胞功能上之
失全或“易感性”早在這以前便已發生。因此,臨床實驗所觀察到的降血脂藥物可以很快
的降低冠心病之併發症,其大部份的機轉應該是經由改善這些血脂異常所造成的非動脈粥狀
硬化因素而來。過去的研究顯示在誘發致死性的心室性纖維顫動時,一個“易感的”心肌
可能與“刺激 (比如心肌缺氧 )”或危險因子的存在同樣重要。心肌細胞膜的生理機制在
誘發心律不整的電氣生理機轉中佔有中心性之地位,因此改變心肌細胞膜的功能亦可改變心
肌的“易感度”。過去已有許多的研究顯示生物細胞膜的脂質成分改變是造成細胞功能變
化的基礎。我們過去的研究也顯示高膽固醇血症會降低心肌細胞膜上鈉離子流的活性。
由於原三年期之研究計劃被刪減為一年之經費,故本年度主要完成原第一年度欲達成之目
標。本研究選取58 位因急性心肌梗塞(AMI)住入本院加護病房中而在第一天併發心室性心律
不整(VT/VF)之病患(A 組),及另58 位性別、年齡及血栓溶解治療相稱的AMI 病患(B 組)。
吾人登錄其冠心病之危險因子,血壓,心跳及檢測其一週內及三個月後的血中總膽固醇(TC)、
高密度膽固醇(HDL-C)、低密度膽固醇(LDL-C)、三酸甘油酯(TG)含量。吾人發現,病人住院當
中的血中脂值濃度均較出院後三個月低。在急性期,A 組病人之LDL-C 較B 組高(137.6 ±35.6
對122.5 ±31.3mg/dl,p=0.002),其平均血壓較低(89.0 ±18.7 對99.8 ±17.4mmHg),而Killip
分類為Ⅲ或Ⅳ者亦較多(16 對5%,p=0.127)。在三個月之慢性期,A 組病患之TC (224.6 ±42.2
對198.2 ±33.2mg/dl,p<0.001),LDL-C (159.4 ±38.1 對128.3 ±30.0mg/dl,p<0.0001)及TG
(179.8 ±102.3 對136.6 ±68.4mg/dl,p=0.009)均較B 組為高。以多變數分析法發現,慢性
期之LDL-C 值(p=0.0009),急性期之平均血壓(p=0.0029),慢性及急性期之TG 值差
(p=0.0466)與急性期病患是否會發生VT/VF 非常有關,為獨立之危險因子。
因此,吾人可據以結論,血脂異常可使急性心肌梗塞病患較易發生心室性心律不整。它可
部份解釋為何近年來發表的大型藥物研究報告中,降血脂藥物可以降低冠心病的猝死率。Background Ventricular tachycardia/fibrillation (VT/VF) developing in the acute stage
of myocardial infarction is a primary factor of sudden cardiac death that still remains as
a major problem in contemporary cardiology. Several animal studies have shown that
dyslipidemia can alter the lipid composition of myocardial membrane and subsequently
increases the susceptibility of cardiac arrhythmia. To the best of our knowledge, there
have been no previous human studies providing the longitudinal evidence of a
relationship between plasma dyslipidemia and arrhythmia. The aim of this study is to
determinate whether dyslipidemia is a predisposing factor of the occurrence of VT/VF
during the acute stage of myocardial infarction.
Methods and Results A total of 58 patients experiencing VT/VF within 24 hours after
the onset of chest pain were matched to 58 patients without such clinical events. Sex
(104 males), age (58+10 years), and the use of thrombolytic therapy (n=82) were
required to matched in both groups initially. To diagnose a patient with dyslipidemia,
the lipid profiles including total cholesterol (TC), high-density lipoprotein cholesterol
(HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were
measured during patients’ hospitalization period (day 1 and day 7) and the outpatient
follow up at the 3rd month after the index event. Other coronary risk factors, as well as
clinical, hemodynamic, and angiographic characteristics were also included in our
assessment. The mean serum levels of TC, HDL-C, LDL-C, and TG measured during
hospitalization were all lower than those measured 3 months later (-9%, P=0.0003; -6%,
P=0.08; -10%, P=0.004; and –9%, P=0.16, respectively). A unique and intriguing
pattern was observed in the patients with incidence of VT/VF. During the acute stage,
they had a higher level of LDL-C (137.6+35.6 vs. 122.5+31.3 mg/dl, P=0.02), a lower
mean blood pressure (89.0 ±18.7 vs. 99.8 ±17.4 mmHg, P=0.002), and a higher
percentage with Killip class III or IV (16 vs. 5%, P=0.127) on the initial arrival. At the
3-month follow up, these patients with experience of VT/VF had a higher level of TC
(224.6+42.2 vs. 198.2+33.2 mg/dl, P<0.001), LDL-C (159.4+38.1 vs. 128.3+30.0 mg/dl,
P<0.0001), and TG (179.8+102.3 vs. 136.6+68.4 mg/dl, P=0.009). In multivariate
analysis, the LDL cholesterol ( P=0.0009) at the 3-month follow up, the mean blood
pressure on arrival ( P=0.0025), and the difference in level of triglyceride between the
first week and the third month ( P=0.0466) were all accounted the independent
predictors for the occurrence of VT/VF in the acute stage of myocardial infarction.
Conclusions This study suggested that dyslipidemia imposed a higher risk of
developing VT/VF in the acute phase of myocardial infarction. It might partly explain
the reason why the current treatment with lipid-lowering drugs could reduce the risk of major coronary events, including sudden cardiac death, in recently published large-scale
study trials
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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