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The linear analysis for heart rate variability (HRV), including time domain method, frequency domain method and time-frequency analysis, has reached a lot of consensus. The non-linear analysis has also been widely applied in biomedical and clinical researches. However, for non-linear HRV analysis, especially for short-term non-linear HRV analysis, controversy still exists, and a unified standard and conclusion has not been formed. This paper reviews and discusses three short-term non-linear HRV analysis methods (fractal dimension, entropy and complexity) and their principles, progresses and problems in clinical application in detail, in order to provide a reference for accurate application in clinical medicine.
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Humanos , Eletrocardiografia , Entropia , Fractais , Frequência CardíacaRESUMO
Ischemic stroke is mainly seen in the elderly,and more than 90％ of the patients have suffered hypertension.Thiazide diuretic is one of the five types of the first-line antihypertensive drugs,its characteristics include relaxation in action,a broad spectrum of anti-hypertension,exact effect,safety,and low price.It has been used for antihypertensive treatment for more than 50 years.As global evidence-based medicine,it is especially suitable for the elderly patients.Thiazide diuretic can effectively reduce the incidence and recurrence of stroke for the elderly hypertensive patients,no matter how it is used alone or in combination with other antihypertensive drugs,the efficiency of thiazide diuretic has withstood the test of time and practice and has been confirmed with clear evidences.Thus,in the elderly patients at high-risk for ischemic stroke,the use of this effective antihypertensive drug should be further emphasized.
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The J-curve phenomenon in the antihypertensive treatment of cardiovascular disease has had more theoretical and experimental evidence and has been recognized by most researchers.However,there are a few related studies and reports about whether antihypertensive treatment has the J-curve phenomenon in ischemic stroke.It has not yet reached a consensus.This article reviews this phenomenon and expecting it to contribute to the blood pressure mangement of ischemic stroke.
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Objective To study the clinical type and features of cerebral watershed infarction (CWI)in eldedy patients and its relationship with plasma lysophosphatidic acid(LPA).Method Analyzed the clinical data of 106 cases of CWI patients(CWI group)confirmed by cranial MRI,and compared plasma LPA levels in patients with different types of CWI,non-CWI patients(non-CWI group,36 cases)and healthy controls(control group,32 cases).Results In CWI group,anterior-cortex type 22 cases,LPA(4.93±0.72)μmol/L,posterior-cortex type 17 cases,LPA(4.75±0.81)μmoi/L,subcortical type 47 cases,LPA (5.46±1.03)μmol/L,mixed type 20 cages,LPA(6.02±1.12)μmol/L.In non-CWIgroup,LPA(5.37±1.24)μmol/L.In control group,LPA(2.92 ±0.36)μmol/L.The levels of LPA significandy increased in various types of CWI(P<0.05 or<0.01).of which mixed type and subcortical type were the highest,and the level of LPA in mixed type WaS higher than that in anterior-cortex type and posterior-cortex type(P<0.05).The level of LPA in non-CWI group was higher than that in control group,but there wss no significant difference compared with various types of CWI.Conclusions Subcortical type is the primal type in elderly CWI patients,the main cause of which is the atherosclerotic plaque formation and lumen stenosis.Platelet activation and its microemboli play an important role in the pathophysiology.LPA levels are significantly higher in various types of CWI,of which mixed type is the highest.LPA can be used as an important molecular marker to guide the sub-type treatment of CWI in elderly patients.
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Objective To investigate the protective effect and its mechanism of prescription Zu Zhong 1 Hao (a traditional Chinese medical prescription, including Astragalus membranaceus, Atractylodes macrocephala, Arisaema cure Bile, Rhizoma pinelliae, the seed of Prunus persiea , Angelica sinensis , Ligusticum Chuanxiong, Paeonia lactiflora , and Pueraria ,etc) pretreatment on focal cerebral ischemia-reperfusion in rats. Methods Sixty SD rats were randomly divided into sham-operation, ischemia-reperfusion, flunarizine and prescription Zu Zhong 1 Hao low-, medium-and high-dose groups (n=10 in each group). A rat model of focal cerebral ischemia-reperfusion was induced by suture method (ischemia for 3 hours followed by reperfusion for 24 hours). Nitric oxide (NO) was measured by the nitrate reductase method; superoxide dismutase (SOD) activity was assessed by the xanthine oxidase method; maiondialde-hyde (MDA) was determined by the thiobarbiturie acid method; and tumor necrosis factor-a(TNF-α) was detected by the enzyme-linked immunosorbent assay (ELISA) method. Results Prescription Zu Zhong 1 Hao significantly improved neurological deficits in focal cerebral ischemia-reperfusion in rats, reduced the content of NO and MDA in brain tissue, increased SOD activity, and down-regulated the expression of TNF-α. Among them, the role of the high-dose group was more significant (P<0. 01). There were also significant differences between the low-and medium-dose groups and the ischemia-reperfusion group (P<0. 05). Conclusions The pretreatment of prescription Zu Zhong 1 Hao has the protective effect on focal cerebral ischemia-reperfusion injury, and its mechanism may be associated with the decreased content of NO and MDA in brain tissue, increased SOD activity, and down-regulated TNF-α expression.
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Objective: To observe the characteristics of dynamic changes of lysophosphatidic acid (LPA) levels in cerebrospinal fluid (CSF) in patients with subarachnoid hemorrhage (SAH) and its relationship with cerebral vasospasm (CVS) and to explore the pathogenesis of CVS. Methods: Sixty-seven patients with SAH diagnozed by clinical and accessory examinations were selected. The LPA levels in CSF were measured at 24 hours, day 7,14, and 28 respectively after the onset of symptoms,and they were compared with a control group. The correlation between LPA levels and CVS on the time course was also observed at the same time. Results: Of the 67 patients with SAH, a total of 29 patients (43.3%) occurred CVS, the average time of occurrence was 6. 6 days. There was no significant difference between the LPA levels in CSF in patients with SAH and the control group at 24 hours after the onset of symptoms; they were significantly higher than the control group at day 7 (P ＜0. 001); they were significantly higher than the control group at day 14 (P ＜ 0. 001), but they were significantly lower than those at day 7 (P ＜ 0. 01); they decreased to baseline at day 28, and there was significant difference compared with the control group. There was no significant difference between the LPA levels in the CVS group and those in the non-CVS group at 24 hours, they were significantly higher than those in the non-CVS group at day 7 (P ＜0. 001), they were still significantly higher than those in the non-CVS group at day 14 (P ＜0. 01); and there was no significant difference between the 2 groups at day 28. Conclusions: The LPA levels in CSF in patients with SAH increased significantly from day 7 to day 14 after the onset of symptoms, and they had obvious association with CVS on the time course. The detection of the LPA levels in CSF may have important significance in predicting the occurrence of CVS.
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Objective To research the significance of the levels of neuron-specific enolase(NSE), S100B and myelin basic protein(MBP) in predicting the severity and prognosis in patients with subarachnoid hemorrhage (SAH). Methods The serum levels ofNSE, SI00B and MBPwere measured within 72 hours after the injury in 36 patients with SAH(SAH group), then the severity of illness and prognosis was evaluated by world federation of neurosurgical societies(WFNS) grade and Glasgow outcome scale(GOS) respectively. Twenty healthy persons were selected as controls(control group). Results After the injury, the serum levels of NSE,SI00B and MBP in SAH group increased significantly compared with those in control group. Moreover, there were significant difference in the serum levels of NSE, S100B and MBP among different groups in different severity of illness and prognosis. Assessed the severity and prognosis by serum levels of NSE 25 μg/L, S100B 1.2 μg/L and MBP 10.0 μg/L after 72 hours of SAH, the specificity of assessing the severity by NSE, SI00B and MBP was 71.43%,61.90%, 66.67%, and the sensitivity was 73.33%,86.62% and 73.33%. At assessment of prognosis,the specificity of NSE, S100B, MBP was 69.57%, 60.87%,65.22%, and the sensitivity was 61.54%,76.92% and 69.23%. Conclusion There are higher specificity and sensitivity in evaluating the severity of illnoss and prognosis in patients with SAH by serum levels of NSE, S100B and MBP.
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Long-term prognosis of stroke rehabilitation is associated with a number of factors, such as age, sex, race, lesion sites and sides, lesion nature and various complications. Under-standing these related factors not only contribute to clinical judgement of prognosis, but also provide the basis for the targeted rehabilitation therapy.
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With the rapid development of medicine,medical ethics and medical philosophy have also made a far step forward.Under the new historical conditions,they are endowed with a new scientific connotation,which is elaborated in the modern version of Hippocratic Oath.