TBARS and cardiovascular disease in a population-based sample

BACKGROUND: Oxygen radicals might play a crucial role in the pathogenesis of various diseases, including atherosclerosis. Thiobarbituric acid reaction substances (TBARS), a biomarker of oxidative stress, have been proposed as a summary measure of total circulating oxidation. However, there is no strong indication that circulating levels of TBARS are increased in patients with atherosclerosis. DESIGN: We evaluated the relation between TBARS and cardiovascular disease (CVD) in a cross-sectional random sample of white men and women from Buffalo, New York. METHODS: Logistic regression was used to estimate the risk associated with high levels of TBARS. The area under the ROC curve was used to evaluate the discriminating power of TBARS. RESULTS: After adjusting for age and gender, TBARS levels were significantly higher in those with prevalent CVD (OR= 1.73, 95% CI=1.32-2.38), compared to those without a CVD diagnosis. These OR were almost 50% higher after correcting for measurement error (ME) (OR=1.93, 95% CI=1.07-3.40). The area under the ROC curve was 0.69 (95% CI=0.62-0.77) and when corrected for ME reached 0.80 (95% CI=0.65-0.89). CONCLUSIONS: Our results indicate that elevated levels of TBARS were associated with increase risk of the prevalence of CVD, but this effect was no longer significant after adjusting for glucose.     

Oxidative stress and glucose levels in a population-based sample.

OBJECTIVES: To examine the relationship between markers of oxidative status and glucose on a population basis. STUDY DESIGN AND SETTING: We report here on a population-based sample of 1315 women and 981 men, aged 35-79 years, randomly selected from residents of Erie and Niagara Counties in western New York between 1996 and 1999. Thiobarbituric reactive substances (TBARS), erythrocyte glutathione (GSH) and plasma glutathione peroxidase (GSH-Px) were measured as markers of oxidative status. Study sample was categorized by quartiles of glucose, degree of abnormality of fasting glucose, and level of metabolic control in patients with diabetes. RESULTS: Men and women in the uppermost quartiles of glucose had higher levels of TBARS (men: Quartile 4 = 1.55 +/- 0.03, Quartile 1 = 1.36 +/- 0.03, women: 1.49 +/- 0.02, 1.30 +/- 0.02 nmol/ml) and lower levels of GSH (men: Quartile 4 = 1.57 +/- 0.03, Quartile 1 = 1.69 +/- 0.03, women: 1.71 +/- 0.03, 1.97 +/- 0.0 mmol/l packed RBCs). In women, compared with normal fasting glucose, impaired fasting glucose was associated with higher levels of TBARS (1.29 +/- 0.01 vs. 1.84 +/- 0.04 nmol/ml), lower levels of GSH (1.85 +/- 0.02 vs. 1.76 +/- 0.05 mmol/l packed RBCs), and higher GSH-Px activity (618.94 +/- 2.64 vs. 644.77 +/- 8.90 IU/l). In women, abnormal fasting glucose was associated with higher levels of TBARS (1.84 +/- 0.04 nmol/ml), lower levels of GSH (1.68 +/- 0.06 mmol/l packed RBCs), and higher levels of GSH-Px (647.72 +/- 9.87 IU/l) than normal or impaired fasting glucose. In men, abnormal fasting glucose was associated with higher TBARS (1.76 +/- 0.04 vs. 1.37 +/- 0.07 nmol/ml), and lower GSH (1.62 +/- 0.05 vs. 2.78 +/- 0.02 mmol/l packed RBCs), than normal fasting glucose. Poor metabolic control was associated with higher TBARS (men: 2.07 +/- 0.08 vs. 1.33 +/- 0.14 nmol/l, women: 2.02 +/- 0.09 vs. 1.35 +/- 0.18 nmol/l) and GSH-Px activity (men: 654.34 +/- 13.45 vs. 599.86 +/- 24.76, women: 660.61 +/- 13.25 vs. 579.42 +/- 27.42 IU/l). CONCLUSIONS: Glucose levels play a role in determining oxidative status in a population sample. The balance between oxidative and antioxidant processes appears to be sensitive to glucose levels with moderate elevations of glucose affecting the oxidative status.     

急性缺血性脑卒中的治疗

在中国急性缺血性卒中是引起死亡及致残的首要原因。每年新发卒中病人约 15 0～ 2 0 0万人。病死率约 80～ 12 0 / 10万人口。 1996年美国食品和药物管理局 (ＦＤＡ )通过了组织纤维溶酶原激活物(ｔＰＡ)静脉溶栓是治疗卒中安全、有效的方法。随后对抗血小板、抗血栓及神经保护剂进行了大规模的临床研究。晚近发现动脉溶栓对治疗大脑中动脉(ＭＣＡ)闭塞效果良好。然而对于卒中治疗单元(ｓｔｒｏｋｅｕｎｉｔ)及卒中综合治疗小组 (ｉｎｔｅｇｒａｔｅｄｓｔｒｏｋｅ ｉｎｔｅｖｅｎｔｉｏｎｔｅａｍ)及早期康复效果则比较难予评价。现结合当…     

Thrombolytic therapy in cerebrovascular disorders.

The knowledge obtained from the ongoing investigational trials of tPA for acute ischemic stroke will not only help establish the appropriate dose range and complication rates but will also further develop the clearly mandatory rapid, aggressive team approach needed to truly treat acute ischemic strokes successfully. Experimental cerebral ischemia data have pointed to the need to treat acute clinical stroke within only a few hours or less to effectively reduce stroke morbidity and mortality. Specifically, with reversible MCA occlusion models of focal cerebral ischemia (dogs and cats), the animals uniformly survive without neurological deficit if the occlusion is for less than 2 to 3 hours. Similarly in primates, MCA occlusion for 3 hours or less will lead to clinical improvement and a decrease in infarct size, with complete recovery generally associated with less than 2 hours of MCA occlusion. Therefore, it appears unlikely that ischemic brain can be salvaged if vascular occlusion persists longer than 4 to 6 hours (similar to the pathophysiology of myocardial ischemia). Further, at least one third of ischemic stroke patients reperfuse spontaneously (and obviously too late) within 48 hours of stroke onset. Several factors believed to be related to successful outcome after thrombolytic therapy are summarized in Table 16. A schematic approach to determining the response to thrombolytic agents in acute ischemic stroke is outlined in Table 17. Zivin succinctly reviews thrombolysis for stroke, both experimental and clinical, and summarizes some of the difficulties of the early clinical stroke trials with thrombolytic agents and speculates about future prospects. He believes tPA may prove valuable in the treatment of some forms of thromboembolic stroke. Its usefulness may depend in part on how quickly the drug can be initiated and the risk of side effects; factors that will require further study. The currently used doses of tPA may be too low to lyse large cerebral arterial clots and, therefore, if current trials do not show a positive treatment response, further trials with higher doses may be indicated. The implications of a potentially effective treatment for truly acute stroke are enormous: stroke will need to be considered by all (lay public through to caregivers) as a true medical emergency, analogous to MI and trauma.(ABSTRACT TRUNCATED AT 400 WORDS)     

Day-to-day dynamics of experience--cortisol associations in a population-based sample of older adults

In 156 older adults, day-to-day variations in cortisol diurnal rhythms were predicted from both prior-day and same-day experiences, to examine the temporal ordering of experience-cortisol associations in naturalistic environments. Diary reports of daily psychosocial, emotional, and physical states were completed at bedtime on each of three consecutive days. Salivary cortisol levels were measured at wakeup, 30 min after awakening, and at bedtime each day. Multilevel growth curve modeling was used to estimate diurnal cortisol profiles for each person each day. The parameters defining those profiles (wakeup level, diurnal slope, and cortisol awakening response) were predicted simultaneously from day-before and same-day experiences. Prior-day feelings of loneliness, sadness, threat, and lack of control were associated with a higher cortisol awakening response the next day, but morning awakening responses did not predict experiences of these states later the same day. Same-day, but not prior-day, feelings of tension and anger were associated with flatter diurnal cortisol rhythms, primarily because of their association with higher same-day evening cortisol levels. Although wakeup cortisol levels were not predicted by prior-day levels of fatigue and physical symptoms, low wakeup cortisol predicted higher levels of fatigue and physical symptoms later that day. Results are consistent with a dynamic and transactional function of cortisol as both a transducer of psychosocial and emotional experience into physiological activation and an influence on feelings of energy and physical well-being.     

Correlates of regular cigarette smoking in a population-based sample of Australian twins

AIMS: To investigate the role of measured risk factors and the influence of genetic and environmental factors on regular cigarette smoking. Design Members of monozygotic and dizygotic, including unlike-sex twin pairs (n = 6257) from a young adult cohort from the Australian Twin Registry. METHODS: Cox proportional hazards models were used to determine whether putative risk factors were significantly associated with regular cigarette smoking. Risk factors were classified into four tiers: tier 1 (parental history, including parental education, alcoholism and cigarette smoking), tier 2 (early home and family influences), tier 3 (early life events, e.g. trauma) and tier 4 (psychiatric symptoms/disorders with onset prior to 14 years), after controlling for gender, zygosity and their interactions. Genetic models were fitted to examine the heritability of smoking behavior before and after controlling for significant covariates from the four tiers. FINDINGS: Parental history of cigarette smoking and alcoholism, parental closeness and home environment, as well as incidence of childhood sexual abuse or other trauma, a history of early onset panic attacks and conduct problems were associated with regular cigarette smoking. Important age interactions were found, particularly for family background risk factors. Regular cigarette smoking was moderately heritable, even after accounting for significant covariates. CONCLUSIONS: Several measured risk factors are associated with regular smoking. While some of the genetic influences on regular smoking may be shared with these risk factors, a significant proportion of the genetic vulnerability to regular smoking is phenotype-specific.     

Adjustment of several spirometric reference equations to a population-based sample in Mexico

OBJECTIVE: To compare several forced spirometry reference equations used in Mexico in order to know which of them have a better fit to a population-based sample. MATERIAL AND METHODS: Spirometric values of 225 healthy subjects 40 years of age or older from Metropolitan area of Mexico City, were compared to several reference equations. The sample is population-based and it was done from June to December 2003. The difference between observed and expected values was calculated. A concordance analysis between both observed and expected values was done and the percentage of subjects under normality lower limit was obtained. RESULTS: The equations with better fit for FEV1 and FVC were: NHANES III for Mexican-Americans and Euro-Americans; and from PLATINO. Predicted values according to Knudson were lower, and those from Cruz-Mérida, larger than observed values. Percentage of subjects below lower limit of normal was closest to 5% in the reference values from PLATINO. CONCLUSIONS: We recommend the use of reference values from the study NHANES III (for Mexican-Americans or European-Americans) and PLATINO.     

Association of arginine vasopressin and arterial blood pressure in a population-based sample

BACKGROUND: The role of arginine vasopressin (AVP) in the development and maintenance of arterial hypertension is controversial. Furthermore, it remains unclear whether chronic treatment with antihypertensive agents modulates levels of AVP, with potential secondary effects on vascular tone and fluid homeostasis. OBJECTIVE: To investigate the relation between plasma AVP and arterial blood pressure in a population-based sample of 534 middle-aged subjects. RESULTS: Overall, levels of AVP were higher in hypertensive subjects (2.15 +/- 0.26 pg/ml; n = 289) than in normotensive subjects (1.45 +/- 0.15 pg/ml; n = 245; P < 0.05). (Hypertension was defined as systolic blood pressure > 160 mmHg and/or diastolic blood pressure > 95 mmHg, or receiving antihypertensive medication.) In untreated individuals, plasma levels of AVP were found to be correlated with both systolic (r = 0.15, P = 0.002) and diastolic (r = 0.14, P = 0.005) blood pressure. The differences between the lowest and highest quartile of AVP levels were 5.1 mmHg (P = 0.03) and 2.6 mmHg (NS) for systolic and diastolic blood pressure, respectively, after adjustment for age and sex. Moreover, it appeared that the relation between AVP and blood pressure was particularly strong in subjects with low levels of renin (< 10 mU/l; n = 118; systolic blood pressure r = 0.24, P = 0.007; diastolic blood pressure r = 0.19, P = 0.03). Specifically, patients receiving monotherapy with diuretics (n = 39) or beta-blockers (n = 54) displayed elevated plasma levels of AVP (2.93 +/- 0.98 pg/ml and 2.74 +/- 0.74 pg/ml respectively); however, only in patients taking diuretics was this finding apparently independent of confounding variables. Other monotherapies with angiotensin-converting enzyme inhibitors (n = 9) or Ca(2+)-antagonists (n = 19) were not associated with levels of AVP. CONCLUSION: The data suggest that plasma levels of AVP display a discernible relationship with arterial blood pressure and hypertension, particularly when renin levels are low. In addition, with the exception of diuretics, no modulation of AVP levels is attributable to the intake of antihypertensive agents as it occurs in a population-based sample.     

Post-prandial triglyceride profile in a population-based sample of Type 2 diabetic patients

Aims/hypothesis Postprandial lipaemia is considered an emerging risk factor for cardiovascular disease also in the Type 2 diabetic population. However, little information exists on the daily triglyceride profile of these patients, especially during everyday life. The aim of the study was to evaluate the daily triglyceride profile of Type 2 diabetic patients during their everyday life.Methods 145 Type 2 diabetic patients (66 men/79 women, age range 45–65 years) at a health district near Naples, Italy, participating in a screening survey for the evaluation of diabetic complications, and 30 non-diabetic subjects of the same area underwent four daily capillary triglyceride profiles by Accutrend (Roche)—a previously validated method.Results Triglyceride values (mmol/l; Means ± SE) were 2.22±0.08 at fasting, decreased before lunch (2.03±0.07), reached a peak 3 h after lunch (2.73±0.09) and remained substantially high before dinner (2.47±0.09) (all p<0.001 vs fasting). The triglyceride profile of non-diabetic subjects was significantly lower at each point (average difference of 0.73 mmol/l). The percentage of patients with values above 2.25 mmol/l was 61% 3 h after lunch and 49% before dinner. Moreover, in 30% of patients with optimal fasting values (<1.69 mmol/l) triglyceride concentrations 3 h after lunch ranged between 1.69 and 2.25 mmol/l, and in 31% they were above 2.25 mmol/l.Conclusion/interpretation Most Type 2 diabetic patients have postprandial triglycerides above optimal concentrations for several hours after meals. Moreover, optimal fasting concentrations are not always a good predictor of postprandial triglycerides.Abbreviations GCT Glucose-cholesterol triglycerides     

脑血管病患者的睡眠异常

脑血管病患者常合并睡眠异常,主要与病变部位、精神心理因素有关.对合并睡眠异常的脑血管病患者应引起重视,积极寻找病因,早期治疗,减少并发症,有利于提高患者的生活质量.文章对脑血管病患者睡眠异常的病因、临床特点、诊断和防治等做了综述.