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Query: UMLS:C0042373 (vascular disease)
 17,070 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Much of the difficulty in assessing the progress of diabetic angiopathy and effects of experimental modes of therapy arises from the lack of quick, simple, inexpensive, and noninvasive tests to perform on the circulatory system of human subjects. We report here on values obtained by the use of mercury-in-rubber strain gauge plethysmography on 15 middle-aged, adult-onset diabetics who had minimal clinical evidence of microangiopathy. Standard tests are described for assessing forearm vascular function at rest, during tonic exercise of the fingers, and after interrupted repetitive exercise of the fingers. When matched against a similar aged nondiabetic group, the diabetics had slightly higher forearm vascular resistance at each level of exercise, a marked reduction (approximately 50 per cent) in capillary filtration coefficient, which is believed to be related to vascular filtering surface area, and a slight reduction in venous capacitance at all levels of exercise. The method of mercury-in-rubber strain gauge venous occlusion plethysmography provides the clinician with a sensitive and inexpensive tool with which to follow the evolution of angiopathy in diabetic patients.
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PMID:Forearm hemodynamics and responses to exercise in middle-aged adult-onset diabetic patients. 65 18

The most important adaptive mechanism to acute hypoxia is alveolar hyperventilation which improves the oxygen uptake in the lung. The delivery of oxygen to the particular organs is regulated according to their vital function. An essential adaptive mechanism can not be observed above an inspiratory O2 partial pressure of 100 mm mercury, corresponding to an altitude of about 3000 m in normals. In contrast, in patients with cardio-pulmonary disturbances adaptive mechanisms take place at far lower altitudes. Especially in patients with arterial hypoxemia, pulmonary hypertension and occlusive vascular disease moderate hypoxia may lead to decompensation of an a priori unstable equilibirum.
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PMID:[Cardiopulmonary adaptation to acute hypoxia (author's transl)]. 79 74

Platelet activation releases thromboxane A2 and serotonin, which acts on blood vessels through a specific, 5-hydroxytryptamine (5-HT2) receptor. The development of ketanserin, the selective 5HT2 receptor blocker, has made it possible to explore the role of serotonin in patients with advanced atherosclerotic disease. Ketanserin in low doses (3 to 30 micrograms/kg) was administered intra-arterially to 23 patients with symptomatic peripheral occlusive vascular disease during peripheral angiography: an additional seven patients received a placebo. The angiographic response was evaluated by coded reading and by computer-assisted measurement of arterial segments in four anatomical regions (pelvis, thigh, knee, and lower leg). Hemodynamic changes were assessed by mercury strain gauge plethysmography and Doppler pressure measurement. Unequivocal vasodilatation was observed in zero of seven placebo-treated patients and in 13 of 23 (57%) treated patients primarily at the level of collateral vessels. Dilation of the geniculate arteries, a major source of collaterals to the calf, was associated with a significant increase in the blood flow delivery to the calf. There was a moderate drop of systemic blood pressure in patients who failed to respond with peripheral vasodilatation. Ketanserin induces hemodynamically significant vasodilatation in some patients with peripheral vascular disease, suggesting that serotonin may contribute to ischemia in some patients with advanced atherosclerosis.
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PMID:Atherosclerosis, peripheral arterial disease and the vascular response to ketanserin. 234 79

There are many clinical applications for non-invasive measurements of limb and digit blood flow, but often plethysmographs are inconvenient to use. Most experimental work has been carried out on patients with vascular disease. The variation of blood flow with various environmental and physiological factors has been investigated. Little information is available on the effects of injury or surgical trauma on blood flow in limbs. Plethysmographic methods measure arterial flow or pulse volume by several techniques including volumetric displacement, electrical impedance, gravimetry and the mercury in rubber strain gauge. Calorimetric, Doppler and isotope clearance techniques have also been applied to the measurement of blood flow in digits. None of these methods fulfils all the criteria for the requirements of an ideal device and some are too complicated, uncomfortable or cumbersome for widespread use. The results from different techniques are compared and the reasons for variability are discussed. Possible mechanisms for the effects of trauma on limb blood flow are suggested. Experimental comparisons of different plethysmographs are described and the requirements for future development of these devices are defined.
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PMID:Non-invasive measurement of limb and digit blood flow. 294 20

Various non-invasive vascular studies have been reported to provide valuable data for selection of the optimum level of amputation in limbs in patients who have vascular disease. We evaluated three such methods: (1) measurement of the change in the transcutaneous PO2 after inhalation of oxygen; (2) determination, by the Doppler method, of segmental blood pressure; and (3) measurement of the temperature of the skin. The records of eighty patients (ninety amputations) were retrospectively reviewed for correlations between the results of the vascular studies and the outcome of the amputation. Measurement of transcutaneous PO2 was found to be the most accurate predictor of successful healing of an amputation; the other two measurements were less reliable. The values for transcutaneous PO2 both at rest and after inhalation of oxygen were significantly different (p less than 0.001) for the patients who had a healed amputation compared with those who had a failed amputation. Regardless of the initial value, if, after inhalation of oxygen, the transcutaneous PO2 reached ten millimeters of mercury or more, it predicted healing of the amputation stump with a sensitivity of 98 per cent. When the level of amputation was selected on the basis of clinical judgment at the time of operation, the sensitivity was only 90 per cent.
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PMID:The role of non-invasive vascular studies in determining levels of amputation. 305 9

Blackfoot disease (BFD) is an endemic peripheral vascular disorder resulting in gangrene of the lower extremities, especially the feet, among residents in a limited area on the southwest coast of Taiwan. In the present study, the concentrations of zinc, cadmium, lead, and copper in urine of BFD patients with matched normal controls are investigated by differential pulse anodic stripping voltammetry (DPASV) on a hanging mercury drop electrode (HMDE). The analytical results indicate that urinary copper, cadmium, and lead of the BFD patients are significantly higher than those of the controls. In addition, the patients showed a significantly lower concentration of zinc in the urine than the normal controls. The possible connection of these elements with the etiology of the disease is discussed.
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PMID:Simultaneous determination of Zn, Cd, Pb, and Cu in urine of patients with blackfoot disease using anodic stripping voltammetry. 750 41

Clinical practice often conflicts with epidemiologic evidence in the management of blood pressure. Antihypertensive therapy is generally prescribed if blood pressure exceeds some arbitrary level, thus committing many persons with minimal cardiovascular risk to long-term drug therapy. By contrast, below that level, regardless of cardiovascular risk, blood pressure reduction is rarely sought. Epidemiologic data, however, consistently show a continuous, positive, linear relationship of the height of both systolic and diastolic blood pressure with the incidence of stroke and heart attack. No threshold level distinguishes those who will have a cardiovascular event from those who will not. In fact, most heart attacks and many strokes occur among persons with "normal" blood pressures. Observational experience suggests that benefit could be obtained from universal blood pressure reduction of even a few millimeters of mercury. This public health strategy can be augmented by identifying those individuals, at every level of blood pressure, whose risk for cardiovascular disease justifies the cost of pharmacologic intervention. Antihypertensive drug therapy will be most efficient and effective if directed at those who, by virtue of their constellation of risk factors or evidence of preclinical vascular disease, are likely to have a heart attack or stroke. The resulting redirection of clinical resources will spare many hypertensive persons whose absolute risk for a cardiovascular event is small, from life-long treatment. At the same time, other persons, currently classified as normotensive, will become candidates for blood pressure reduction because their cardiovascular risk is high.
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PMID:Blood pressure management: individualized treatment based on absolute risk and the potential for benefit. 825 86

In this study, compliance, a mechanical characteristic of the lower leg arteries, was measured noninvasively. Changes in blood volume and pressure were measured using impedance plethysmography and a mercury sphygmomanometer, respectively. Compliance was calculated by dividing the change in blood volume by the change in pulse pressure (systolic-diastolic pressure). Subjects were 24 asymptomatic persons ranging from 30 to 58 years and 14 diabetics ranging from 41 to 59 years. Peak compliance, mean pressure, and systolic pressure were statistically analyzed using a t test between the asymptomatic and diabetic groups. The average peak compliance of the asymptomatic and diabetic groups was measured as 2.79 and 1.82 microL/mmHg/cm, respectively, and these were significantly different (p < 0.01). It was also found that compliance is a better parameter in differentiating vascular disease than the mean or systolic blood pressure.
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PMID:Measurement of leg arterial compliance of normal subjects and diabetics using impedance plethysmography. 1037 58

Epidemics of vascular disease caused by toxins and infectious agents affecting both humans and animals have been common in history. Examples of agents implicated include anorexients, ergotamine, mercury, arsenic, vinyl chloride, thorotrast, plant alkaloids, nitrites, toxic oil, tryptophan and bacterial, viral and parasitic infections. A major characteristic of these disorders is endothelial dysfunction, which may manifest itself in vasospastic disorders, sclerodermiform skin lesions, fibrosis, osteolytic lesions, polyneuropathy and portal and pulmonary hypertension. Angiosarcoma may also be a late outcome. These diseases are more common than is generally appreciated. The aetiology is usually multifactorial. This and other factors contribute to delayed recognition.
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PMID:Epidemics of vascular toxicity and pulmonary hypertension: what can be learned? 1067 26

Mercury, cadmium, and other heavy metals have a high affinity for sulfhydryl (-SH) groups, inactivating numerous enzymatic reactions, amino acids, and sulfur-containing antioxidants (NAC, ALA, GSH), with subsequent decreased oxidant defense and increased oxidative stress. Both bind to metallothionein and substitute for zinc, copper, and other trace metals reducing the effectiveness of metalloenzymes. Mercury induces mitochondrial dysfunction with reduction in ATP, depletion of glutathione, and increased lipid peroxidation; increased oxidative stress is common. Selenium antagonizes mercury toxicity. The overall vascular effects of mercury include oxidative stress, inflammation, thrombosis, vascular smooth muscle dysfunction, endothelial dysfunction, dyslipidemia, immune dysfunction, and mitochondrial dysfunction. The clinical consequences of mercury toxicity include hypertension, CHD, MI, increased carotid IMT and obstruction, CVA, generalized atherosclerosis, and renal dysfunction with proteinuria. Pathological, biochemical, and functional medicine correlations are significant and logical. Mercury diminishes the protective effect of fish and omega-3 fatty acids. Mercury, cadmium, and other heavy metals inactivate COMT, which increases serum and urinary epinephrine, norepinephrine, and dopamine. This effect will increase blood pressure and may be a clinical clue to heavy metal toxicity. Cadmium concentrates in the kidney, particularly inducing proteinuria and renal dysfunction; it is associated with hypertension, but less so with CHD. Renal cadmium reduces CYP4A11 and PPARs, which may be related to hypertension, sodium retention, glucose intolerance, dyslipidemia, and zinc deficiency. Dietary calcium may mitigate some of the toxicity of cadmium. Heavy metal toxicity, especially mercury and cadmium, should be evaluated in any patient with hypertension, CHD, or other vascular disease. Specific testing for acute and chronic toxicity and total body burden using hair, toenail, urine, serum, etc. with baseline and provoked evaluation should be done.
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PMID:The role of mercury and cadmium heavy metals in vascular disease, hypertension, coronary heart disease, and myocardial infarction. 1740 90


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