Cerebral Blood Flow Velocity,Erythrocyte Deformability and Alcohol Intake

The aim of the study was to determine if there is a relationship between low blood flow velocity in the cerebral arteries and erythrocyte deformability in heavy alcohol drinkers. The study comprised 47 heavy alcohol drinkers (mean age 47 years). All of them drank daily more than 84 g of alcohol (84–400 g). Blood flow velocity (V _mean) in intracranial arteries was determined by transcranial Doppler. Erythrocyte membrane biophysical properties were estimated using the method of cation-osmotic haemolysis (COH). The present study revealed a significant decrease in V _mean in all examined arteries, with p= <0.01 in the middle (MCA) and posterior (PCA) cerebral arteries and p= <0.05 in the anterior cerebral artery (ACA) when compared with age-matched controls. Cation-osmotic haemolysis in the low ionic strength of the incubating medium (15.4 mmol/l NaCl) as well as in the high ionic strength (123.2–154.0 mmol/l NaCl) was significantly decreased (p<0.001–0.01). This means that changes in both parts of the erythrocyte membrane (actin–spectrin complex and membrane lipid bilayer) are the cause of decreased erythrocyte deformability. We conclude that one of the factors which can cause low blood flow velocity (a possible risk factor for stroke) is decreased cation-osmotic haemolysis of erythrocytes.     

Meal induced changes in hepatic and splanchnic circulation: a noninvasive Doppler study in normal humans

Summary The haemodynamic effects of a meal on the splanchnic and hepatic circulation were evaluated in 30 healthy volunteers, using Doppler ultrasonography. The resistance index (RI) of the superior mesenteric artery and of the left and right intrahepatic arteries, the portal vein blood flow as well as the ratio between maximal velocity in the left and right intrahepatic arteries and the adjacent portal vein were measured initially, then 15, 30, 45, and 60 min after the ingestion of a standard balanced liquid meal. Postprandial haemodynamic changes were maximal 30 min after the meal; at that time, mesenteric artery RI decreased significantly [mean –11% (SEM 14%)] whereas portal vein blood flow increased markedly [mean +79% (SEM 14%)]; a significant increase in hepatic artery RI was observed in both liver lobes. The ratio between maximal velocities of the intrahepatic artery and the intrahepatic portal vein was reduced significantly; this ratio decreased more markedly in the right lobe of the liver. These findings would suggest that there was an adaptation of hepatic artery to portal vein blood flow after a meal. The subsequent increase in intrahepatic portal vein flow velocity was found to be greater in the right lobe of the liver.     

Impaired cerebral and systemic hemodynamics under cognitive load in young hypotensives: a transcranial Doppler study

Reduced sympathetic outflow and deficits in cerebral hemodynamics have been considered as possible factors mediating the impaired cognitive performance in essential hypotension. However, the relationship between systemic blood pressure (BP), cerebral blood flow and cognitive functioning is still poorly understood. The present study was aimed at clarifying the physiological processes underlying cerebral and systemic hemodynamics in young hypotensives during cognitive engagement. Doppler sonography blood flow velocities in both middle cerebral arteries were measured from 17 hypotensives and 15 normotensives during a working memory task. Impedance cardiographic and BP measures were also recorded continuously. Lower increases in systolic and diastolic BP were observed in hypotensives. However, no evidence of lower sympathetic control was found for this group, as assessed by pre-ejection period. Flow velocity in middle cerebral arteries showed a lower increase in hypotensives throughout the task. Moreover, significant positive correlations between BP changes and blood flow velocities in middle cerebral arteries during the task were obtained for this group only, suggesting a less effective cerebral autoregulation. No difference was found between groups in task performance. Results suggest that during cognitive challenge hypotensives show impaired hemodynamic adjustments, both central and peripheral. However, such alterations do not directly affect cognitive performance, at least under moderate cognitive load.     

中国五地区饮酒情况及相关问题调查Ⅱ.饮酒者健康状况调查

目的：了解我国社区普通人群饮酒者的健康状况和饮酒相关疾病的患病率，探讨饮酒与健康的关系。方法：应用定式检查问卷，调查我国五地区24992例受试者过去一年中饮酒、总体健康状况(自评)和饮酒相关疾病的患病情况。结果：97％的饮酒者和92．2％的非饮酒者认为自己的健康状况较好，3．0％的饮酒者和7．8％的非饮酒者认为较差。总体健康状况的逐步多因素回归分析结果表明是否饮酒和饮酒年限是影响健康的重要因素。饮酒相关疾病的单因素分析结果显示饮酒者胃炎或胃溃疡、偏头痛、腰背痛和失眠的患病率高于非饮酒者，心脏病、脑梗塞或脑出血、听力或视力障碍和糖尿病的患病率低于非饮酒者。分层控制年饮酒量后，胃炎、胃溃疡和失眠的患病率随年饮酒量增加而增加，二者呈非线性相关，非饮酒者和重度饮酒者心脑血管疾病的患病率高于轻中度饮酒者，患病率与饮酒量呈“V”字型关系，但趋势检验结果未表明二者直接相关。结论：我国社区普通人群中，是否饮酒及饮酒者的饮酒时间长短是饮酒健康的重要因素，饮酒能够增加消化道疾病和失眠的发病率，轻中度饮酒则对心脑血管疾病的发生具有保护作用。调查者的健康状况可能是各因素综合作用的结果。     

经颅多普勒超声检测动脉硬化症330例结果分析

目的：探讨经颅多普勒诊断脑动脉硬化症的可行性；方法：分析３３０例临床诊断为脑动脉硬化症病人的经颅多普勒检查结果；结果：２５７例（占７７．８％）病人符合脑动脉硬化血流改变，３１例（１２．１％）血流速度增快，１５０（５８．４％）血流速度降低，１２例（４．７％）有脑动脉狭窄表现。结论：经颅多普勒是一种安全、易行、无创的脑动脉硬化症辅助诊断手段。     

Differences in brain and liver blood flow during and after acute blood loss in rats with different resistance to circulatory hypoxia

Variations of blood flow and vascular resistance in the common carotid arteries and of blood flow in the hepatic artery and portal vein are examined during and after acute massive blood loss in rats with low and high resistance to circulatory hypoxia. In rats with low resistance, arterial pressure and the rates of cerebral and hepatic blood macro- and microflow, which have decreased during blood loss, continued to fall during the posthemorrhagic period. After cessation of bleeding, a transient arterial pressure rise to 70 mm Hg is observed in rats with high resistance, while the blood flow via carotid arteries increases to 65% of its initial value, being maintained at this level throughout the period of changes in carotid vascular resistance; intrinsic hepatic arterial blood flow increases to 115% of baseline value, while the portal vein blood flow and hepatic microflow increase to 75%. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 3, pp. 253–257, March, 1997     

Long-term alcohol consumption and brown adipose tissue in man

Summary The purpose of the present work was to study whether long-term alcohol consumption in man affects the develeopment of brown adipose tissue. The adipose tissue around the thoracic aorta and common carotid arteries was collected at medicolegal autopsies on adults with a positive record of heavy alcohol consumption. Adults without any evident history of alcohol consumption served as controls. Histochemical reactions of the oxidative mitochondrial enzymes, cytochrome oxidase and succinate dehydrogenase were studied in samples of this adipose tissue and the activities of the enzymes were measured biochemically.There was histological evidence of some multilocular adipose tissue around the thoracic aorta and common carotid arteries of the alcohol consumers, whereas the adipose tissue from the non-drinkers was mostly unilocular resembling white adipose tissue. Histochemical evidence of brown adipose tissue was found in all alcohol consumers, but also in some of the controls. Biochemical cytochrome oxidase (CYO) and succinate dehydrogenase measurements in isolated mitochondria showed activity in 70% of the cases of drinkers and in one of the eight controls. Activity of CYO was measurable in the mitochondria from two other controls. The protein content of the samples from the alcoholics was twice that of the controls. The results suggest that chronic alcohol intake may induce a change in the white adipose tissue around the thoracic aorta and common carotid arteries of human adults into brown fat.     

Evaluation of extracranial blood flow in Parkinson disease

Decreased cerebral flow velocities in Parkinsonian patients were reported previously. Because of the limited data on vascular changes in Parkinson disease (PD), which may have a vascular etiology, we aimed to disclose any possible cerebral hemodynamic alteration in Parkinsonian patients. We prospectively evaluated 28 non-demented, idiopathic parkinsonian patients and 19 age and sex matched controls with Doppler sonography. Flow volumes, peak systolic flow velocities, and cross-sectional areas of vertebral and internal carotid arteries (ICA) were measured and compared between patients and controls. Correlation of patient age and disease duration with Doppler parameters was observed; and each Doppler parameter of patients within each Hoehn-Yahr scale was compared. There was no significant difference of measured parameters between groups. No correlation was found between disease duration and age with flow volume, cross-sectional area or peak systolic velocity. Hoehn-Yahr scale was not found having significant relation with Doppler parameters. Values of vertebral, internal carotid and cerebral blood flow volumes (CBF), peak systolic velocities, and cross-sectional areas were not significantly different between Parkinsonian patients and age and sex matched controls. Although regional blood flow decreases may be seen as reported previously, Parkinson disease is not associated with a flow volume or velocity alteration of extracranial cerebral arteries.     

Cerebral blood flow in essential hypotension during emotional activation

Variations of blood flow velocity in the left and right middle cerebral arteries (MCA) were measured in 20 hypotensive women and 20 normotensive control subjects during emotional stimulation using functional transcranial Doppler sonography (fTDS). The emotional stimuli were composed of three series (neutral, pleasant, and unpleasant) of 20 pictures from the International Affective Picture System (IAPS). Both groups exhibited greater increases in right than left MCA blood flow during emotional stimulation. However hypotensive subjects showed smaller increases in blood flow than did normotensive controls. Furthermore hypotensives exhibited lower MCA blood flow velocity in both hemispheres at rest than did normotensives. Nevertheless the hypotensive group rated the emotional pictures as more arousing than did the control group. Results suggest a decreased blood flow, in addition to peripheral, in the central nervous system (CNS) of hypotensives, which was associated with normal emotional responses for both valence and hemispherical asymmetry, but also with a general increase of arousal levels. This dissociation might be related to an increase in anterior cerebral arteries (ACA) blood flow and/or to hypotension-mediated baroreceptors' up-regulation to the reticular system.     

Do insulin-like growth factors mediate the effect of alcohol on breast cancer risk?

Despite a large number of epidemiologic studies demonstrating an increased risk of breast cancer in association with alcohol consumption, a causal relationship between alcohol intake and breast cancer risk remains to be determined. Several biological mechanisms have been proposed, but none of them explains well the features of the association, i.e. a modest increase in risk, a limited range of dose-response relationship and no further increase in risk among heavy drinkers. A new mechanism underlying a possible biological role of alcohol in breast cancer is proposed in this paper. Moderate consumption of alcohol increases the production of insulin-like growth factors (IGFs) by the liver and elevated IGFs via circulation stimulate or promote the development and/or growth of breast cancer. The effect of alcohol on IGF production declines among heavy drinkers as alcohol-caused liver-function damage results in no further increase in IGF production. Therefore, compared to moderate drinkers, heavy alcohol users do not have a higher risk of breast cancer.     

Cognitive performance and cerebral blood flow in essential hypotension

In the present study cerebral blood flow was assessed in 40 subjects with chronically low blood pressure and 40 normotensive controls at resting conditions and during the execution of a cued reaction time task. Blood flow velocities were recorded by means of transcranial Doppler sonography in both middle cerebral arteries. In hypotensives flow velocity at rest was reduced bilaterally. During the anticipation of the stimuli, which the subjects had to respond to, a predominantly right hemispheric increase of flow velocity was observed in both groups. This increase was significantly less pronounced in the hypotensive group. Hypotensives showed longer reaction times, and there was a negative correlation between the extent of the flow velocity increase and the reaction times. This study is the first to demonstrate a reduced cerebral perfusion and maladaption of blood flow to cognitive demands due to essential hypotension.     

Middle cerebral artery blood velocity during exercise in patients with atrial fibrillation.

Atrial fibrillation limits the ability to increase cardiac output during exercise and may, in turn, affect the exercise-associated elevation in cerebral perfusion. In nine patients with atrial fibrillation (AF) and in five age-matched healthy subjects, middle cerebral artery blood velocity (MCA Vmean) was measured during incremental exercise using the transcranial Doppler. The AF patient group exhibited a lower aerobic capacity than the control group [peak work rate: 106 W (71-153 W; median and range) vs. 129 W (118-1.9 W) and maximal oxygen uptake: 1.4 l min-1 (1.0-1.9 l min-1) vs. 1.7 l min-1 (1.4-2.2 l min-1); P = 0.05]. At rest, MCA Vmean was not significantly different between the two groups [43 cm s-1 (39-56 cm s-1) vs. 52 cm s-1 (40-68 cm s-1)]. During intense cycling, the increase in MCA Vmean was to 51 cm s-1 (40-78 cm s-1) (9%) in the AF group and lower than in the healthy subjects [to 62 cm s-1 (50-81 cm s-1) 23%; P < 0.05], which corresponded with the smaller than expected increase in cardiac output [156% (130-169%) vs. 180%]. Thus, there was a correlation between the increase in MCA Vmean and the ability to increase cardiac output (r2 = 0.55, P < 0.01). We suggest that, during exercise with a large muscle mass, atrial fibrillation affects the ability to elevate cerebral perfusion, and this results from an impaired ability to increase cardiac output.     

Does a U-shaped relationship exist between alcohol use and DSM-III-R mood and anxiety disorders?

BACKGROUND: In recent community surveys, abstainers and heavy drinkers of alcohol have reported more mood and anxiety symptoms than moderate drinkers (U-shaped relationship). The present study was aimed at extending this finding by investigating this potential U-shaped relationship using structured diagnostic interviews to assess mood and anxiety disorders. METHODS: Data came from two contemporaneous surveys, the National Comorbidity Survey (NCS; N=6780) and the Mental Health Supplement of the Ontario Health Survey (OHS-MHS; N=7001). The University of Michigan Revision of the Composite International Diagnostic Interview (UM-CIDI) was used to make DSM-III-R psychiatric diagnoses in both surveys. Three mutually exclusive lifetime alcohol use categories were compared: (1) Alcohol abstainers-individuals reporting no alcohol use or less than 12 drinks in any year throughout their life. (2) Moderate drinkers-individuals that did not meet criteria for alcohol abstainers or problem drinkers. (3) Problem drinkers-DSM-III-R lifetime alcohol abuse, dependence or hazardous levels of alcohol use. RESULTS: After controlling for demographic variables, alcohol abstainers were not found to have significantly higher rates of mood and anxiety disorders in comparison with moderate drinkers. However, problem drinking was significantly associated with mood and anxiety disorders. CONCLUSIONS: Across both surveys, there was no evidence of a U-shaped relationship between lifetime alcohol consumption and lifetime mood and anxiety disorders.     

Deficient adjustment of cerebral blood flow to cognitive activity due to chronically low blood pressure

The present study aimed to investigate aberrances in the adjustment of cerebral blood flow to cognitive activity due to chronically low blood pressure. By means of transcranial Doppler sonography blood flow velocities in both middle cerebral arteries (MCA) were recorded during the execution of a serial subtraction task in 40 subjects with constitutional hypotension and 40 normotensive control persons. Additionally, blood pressure was continuously monitored. As a main result significant correlations between the task-induced changes in blood pressure and those in MCA blood flow velocities were found in hypotensives, but not in control subjects. The dependence of the regulation of cerebral blood flow on blood pressure points towards deficits in cerebral autoregulation in hypotension. Over the total sample the extent of the task-induced MCA flow velocity increase was positively related to cognitive performance. This underlines the importance of the adjustment of cerebral blood flow to current demands for optimal cognitive functioning.     

Moderate alcohol intake is related to increased heart rate variability in young adults: Implications for health and well‐being

Epidemiological literature indicates that the relationship between alcohol consumption and health outcomes reflects a J‐shaped curve such that moderate alcohol consumption confers a protective effect in comparison to abstinence, while heavy consumption is associated with poorer health. While heart rate variability (HRV) may underpin the relationship between drinking and poor health in heavy drinkers, it is unclear whether HRV is increased in moderate, habitual drinkers relative to nonhabitual drinkers. HRV and drinking habits were assessed in 47 volunteers. Results supported hypotheses suggesting that moderate, habitual drinking increases HRV. Although not supported by a significant interaction between drinking group and sex, planned follow‐up analysis also revealed that these findings may be specific to males. Regardless, results highlight HRV as a candidate mechanism for the findings reported in the epidemiological literature.     

Attenuated cortisol response to alcohol in heavy social drinkers.

Individual differences in response to stress may play a role in the development and maintenance of addictive behaviors. While there is evidence that people with a biological family history for alcoholism have a blunted cortisol response to alcohol, data are lacking in other at-risk subgroups, such as heavy social drinkers. The present study examined salivary cortisol response to administration of 0.0, 0.4 (2 drink equivalent), and 0.8 g/kg (4 drink equivalent) alcohol in two groups of social drinkers: heavy drinkers (n=32) and light social drinkers (n=23). The study was conducted double-blind and drink-order was counterbalanced between groups. Salivary cortisol and subjective measures were obtained at predrink baseline, and 15, 45, 105, and 165 min after beverage consumption. Results showed a significant groupxdosextime interaction (p<0.005), with alcohol (0.8 g/kg) producing an attenuated cortisol response in heavy drinkers compared to the light drinkers during the declining phase of the BAC. This outcome remained even after controlling for the effects of smoking status, family history of alcoholism, sex, and negative affect ratings during the session. Neither placebo nor the lower dose of alcohol significantly increased cortisol levels. In sum, a relatively high dose of alcohol produced a smaller increase in cortisol in heavy drinkers compared to light drinkers. The reduced cortisol reactivity in the heavier drinkers is consistent with reports that individuals at risk for alcoholism are hyporesponsive to physical and psychological stress. Further research may help determine whether alteration in cortisol response to alcohol is a biological marker of the propensity to abuse alcohol.     

Alcohol and cardiovascular health

The substantial medical risks of heavy alcohol drinking as well as the probable existence of a less harmful or safe drinking limit have been evident for centuries. Modern epidemiology studies suggest lowered risk of morbidity and mortality among lighter drinkers. Thus, defining “heavy” drinking as ≥ 3 standard drinks per day, the alcohol-mortality relationship is a J-curve with risk highest for heavy drinkers, lowest for light drinkers and intermediate for abstainers. A number of non-cardiovascular and cardiovascular problems contribute to the increased mortality risk of heavier drinkers. The lower risk of light drinkers is due mostly to lower risk of the most common cardiovascular condition, coronary heart disease (CHD). These disparate relationships of alcoholic drinking to various cardiovascular and non-cardiovascular conditions constitute a modern concept of alcohol and health. Increased cardiovascular risks of heavy drinking include: (1) alcoholic cardiomyopathy, (2) systemic hypertension (high blood pressure), (3) heart rhythm disturbances, and (4) hemorrhagic stroke. Lighter drinking is not clearly related to increased risk of any cardiovascular condition and, in observational studies, is related to lower risk of CHD, ischemic stroke, and diabetes mellitus. A protective hypothesis for CHD is supported by evidence for plausible biological mechanisms attributable to ethyl alcohol. International comparisons and some prospective study data suggest that wine is more protective against CHD than liquor or beer. Possible non-alcohol beneficial components in wine (especially red) support possible extra protection by wine, but a healthier pattern of drinking or more favorable risk traits in wine drinkers may be involved.     

Suitable image parameters and analytical method for quantitatively measuring cerebral blood flow volume with phase-contrast magnetic resonance imaging

The aim of this study was to determine suitable image parameters and an analytical method for phase-contrast magnetic resonance imaging (PC-MRI) as a means of measuring cerebral blood flow volume. This was done by constructing an experimental model and applying the results to a clinical application. The experimental model was constructed from the aorta of a bull and circulating isotonic saline. The image parameters of PC-MRI (repetition time, flip angle, matrix, velocity rate encoding, and the use of square pixels) were studied with percent flow volume (the ratio of actual flow volume to measured flow volume). The most suitable image parameters for accurate blood flow measurement were as follows: repetition time, 50 msec; flip angle, 20 degrees; and a 512 x 256 matrix without square pixels. Furthermore, velocity rate encoding should be set ranging from the maximum flow velocity in the vessel to five times this value. The correction in measuring blood flow was done with the intensity of the region of interest established in the background. With these parameters for PC-MRI, percent flow volume was greater than 90%. Using the image parameters for PC-MRI and the analytical method described above, we evaluated cerebral blood flow volume in 12 patients with occlusive disease of the major cervical arteries. The results were compared with conventional xenon computed tomography. The values found with both methods showed good correlation. Thus, we concluded that PC-MRI was a noninvasive method for evaluating cerebral blood flow in patients with occlusive disease of the major cervical arteries.     

Perception of posture and cerebral blood flow.

The perception of posture in man is made possible by the information of the vestibular organs, the visual system, the proprioception and the blood volume distribution. The present study examined the cerebral blood flow velocity (CBFV) and the fluid volume of the thoracic cavity under different pressure conditions and their effects on the perception of posture. Changes in blood flow velocity were measured by transcranial Doppler sonography (TCD), and changes in the blood volume distribution of the upper torso were registered by impedance plethysmography. The results indicated that the cerebral blood flow volume and the thoracic blood volume changed in the same manner. Lower Body Positive Pressure (+30 mmHg) led to an increase in central volume and CBFV. During the Lower Body Negative Pressure Treatment (-30 mmHg), the central blood volume and the cerebral blood flow velocity decreased while venous pooling occurred. Additionally, the changes in both parameters were associated with an altered posture perception. The correlations between the SHP and the two physiological parameters cerebral blood flow velocity and fluid shift in the upper thorax indicate that the fluid shift in the thoracic cavity was more closely related to the SHP than to the changes in cerebral blood volume.     

Alcohol use, urinary cortisol, and heart rate variability in apparently healthy men: Evidence for impaired inhibitory control of the HPA axis in heavy drinkers.

Alcoholism and heavy drinking are associated with a number of physiological, behavioral, affective, and cognitive problems. One such problem involves dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, with alcoholics showing higher basal cortisol levels and reduced inhibitory feedback control. In addition, alcohol consumption is associated with decreased heart rate variability (HRV). In the present study we examined the relationships among alcohol consumption, cortisol excretion, and HRV in 542 apparently healthy men. Men in the top tertile of self-reported alcohol consumption had higher cortisol levels and lower HRV compared to men in the lower two tertiles of alcohol consumption. In addition, the inverse relationship between cortisol and HRV was greatly attenuated in the heavy drinking group even after accounting for a number of potential confounding factors. These results support prior research on the HPA axis dysregulation in alcoholics and suggest impaired inhibitory control of the HPA axis in heavy drinkers. The findings are consistent with the neurovisceral integration model, which links central and peripheral processes, and may provide a comprehensive framework for the future investigation of the complex mix of physiological, behavioral, affective, and cognitive factors which comprise the heavy drinking phenotype.