Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.01 seconds)

The principal emphasis in the past has been on the physical characteristics of the vein wall and to some extent the flow characteristics of the blood it contains. The interaction between the blood cells and the venous endothelium has been largely neglected until recently. This brief review summarises the secretion by the endothelium of such important substances as fibrinolytic agents, antiplatelet agents and venodilators. Many of these secretory activities are modulated by the wall shear stress which in turn is related to the rheological properties of the blood. The rheological properties of bulk venous blood have been shown to be significantly abnormal in patients with venous hypertension. Such haemodynamic and haemorheological alterations also play an important role in the interaction between the formed elements of blood and the vessel wall. Most recently this has assumed the importance in relation to the margination and adhesion of white cells to the endothelium and the subsequent activation of the white cells. Interaction between the circulatory blood and the venous endothelium probably plays an important role in the pathophysiology of both simple varicose veins and the more serious complications of venous disease such as thrombosis.
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PMID:Influence of blood cells and blood flow on venous endothelium. 880 35

The non-healing leg ulcer is examined by discussing three disease processes: peripheral vascular occlusive disease (PVOD), chronic venous insufficiency (CVI), and vasculitis. For PVOD, management decisions are based on risk factors and disease history. Comprehensive management includes the discontinuation of smoking, exercise conditioning and regulation of diabetes, hyperlipidemia, hypertension, and the appropriate application of anticoagulant/antiplatelet drugs. Methods of surgical management include bypass with autogenous or synthetic material in addition to reconstructive surgery with patch angioplasty or extra-anatomic bypass, amputation, percutaneous transluminal angioplasty/stents, thrombolytic infusion, atherectomy, intraluminal ultrasound, and angioscopy. The optimal healing environment for all ulcers prevents contamination, pain, and fluid loss. In CVI, higher venous pressure in the veins of the lower limb during exercise results in ambulatory venous hypertension and ulceration. Various theories are associated with the disease and ulceration process; the classic treatment of elevation, ambulation, and compression for venous disease remains unchallenged. Diagnosis is based on history, physical examination, invasive venography, and/or non-invasive studies. Two groups of vasculitic disorders that share varying degrees of vascular inflammation and necrosis are arteritis (lupus, erythematosus, periarteritis nodosa, dermatomyositis) and blood dyscrasias (sickle cell disease, thalassemia). Leg ulcers associated with vasculitis are due to inadequate tissue oxygenation at the local level, are typically chronic, slow to heal, and commonly recur.
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PMID:The non-healing leg ulcer: peripheral vascular disease, chronic venous insufficiency, and ischemic vasculitis. 939 80

Obesity may either be unspecific as indicated by an increased body mass index (BMI) or due to an abnormal fat-distribution as indicated by an increased waist-to-hip ratio (WHR). The latter is frequently associated with deteriorations of glucose tolerance, hypertriglyceridaemia and hypertension (the metabolic syndrome), a syndrome which is among the strongest risk factors of ischemic heart disease. It is important to note that visceral obesity is a frequent feature of the polycystic ovary syndrome. Also, weight gain after menopause is often associated with a particular increase of the WHR. Obesity as indicated by an increased BMI (> 30 kg/m2) is a weak but easily detectable risk marker of venous thrombotic disease. This risk needs to be considered in clinical practice since obesity was shown to enhance the power of precipitating risk factors of venous disease such as pregnancy, surgery or estrogen treatment.
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PMID:[Obesity and thrombotic vascular diseases]. 962 33

The purpose of this review is to define animal models of chronic venous disease and to demonstrate how animal studies can impact our understanding and treatment of this disorder. To this end an extensive literature search was conducted highlighting potential animal models of chronic lower extremity venous disease. Scientific investigations using animals to study particular aspects of this disease are also reviewed. This review was conducted by members of the Committee on Research of the American Venous Forum to help provide direction for future venous research endeavors. Useful models of chronic venous occlusive disease involve controlled ligation of a major lower limb vein and multiple tributaries. Such a model can provide sustained venous hypertension and studies using this model have confirmed that an isodiametric graft can provide early hemodynamic relief. Models of primary, postphlebitic, and isolated chronic deep venous insufficiency are available for study. Valve repair or transplantation can positively impact the insufficiency observed in these models. Investigations into valve substitutes have generally been disappointing or are undergoing early evaluation. In conclusion, animal models for the study of some aspects of chronic venous disease do exist and have already affected our clinical approach to patients. The scientific study of basic pathophysiology, diagnostics, end-organ response, and long-term surgical treatments of this disorder in well-controlled animal experiments have not been conducted.
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PMID:Animal models for the study of lower extremity chronic venous disease: lessons learned and future needs. 973 30

Skin damage in the presence of chronic venous disease is partially mediated through leukocytes. The endothelium is activated and exhibits proliferation in the skin. Up-regulation of vascular endothelial growth factor (VEGF) expression in the skin of patients with chronic venous disease has been demonstrated with immunohistologic techniques. Abnormal VEGF expression can have local deleterious effects. The aim of this study was to determine whether patients with chronic venous disease have elevated plasma levels of VEGF. We conducted a prospective study with 30 patients with varicose veins of clinical, etiologic, anatomic, and pathologic class C3 (normal skin, n = 15) and C4 (trophic skin changes, n = 15) and 25 control subjects with no clinical evidence of venous or arterial disease of the lower limb. Blood samples were collected from a foot vein of each subject before and after a period of experimental venous hypertension produced by means of standing. Assay of VEGF protein was performed with a sandwich enzyme-linked immunosorbent assay. Plasma VEGF level was elevated in both groups of patients with venous disease compared with the control group. The median VEGF levels among patients were 81 pg/mL (interquartile range [IQR] 56 to 122) supine and 98 pg/mL (IQR 63 to 153) after standing for 30 minutes. Median VEGF levels among control subjects were 52 pg/mL (IQR 35 to 71) lying supine and 60 pg/mL (IQR 39 to 105) after standing for 30 minutes. Experimental venous hypertension caused a small rise in VEGF levels among the patients but not the control subjects. Further studies are required to determine whether increased VEGF expression contributes to tissue injury in chronic venous disease.
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PMID:Increased plasma vascular endothelial growth factor among patients with chronic venous disease. 973 65

The superior vena cava obstruction is a relatively rare condition. We report the case of a 42 year old man suffering of hypertension for about fifteen years. He reported a cervical and thoracic pain for one year, that was related to a 95% of occlusion on the right coronary artery. An angioplasty has been done but the patient still related the thoracic pain. Afterwards the patient had recurrent episodes of right hemiplegia and hypertensive emergencies that have been treated with anti-hypertensive agents. A venous disease was suspected because of cyanosis in the face especially when episodes of transient ischemic attacks occurred. A venography showed obstruction of the right jugular vein near the junction with the superior vena cava. In conclusion, it was not possible to define with certainty the relationship between the two pathologies presented by the patient, even so, we call attention to the improvement of the neurological symptoms after the control of superior vena cava obstruction with the treatment.
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PMID:[Transient ischemic attacks in a patient with superior vena cava obstruction: case report]. 975 35

Perforator incompetence, caused by primary valvular incompetence or by previous deep venous thrombosis, contributes to ambulatory venous hypertension and the development of chronic venous disease. Although the exact role and contribution of perforators to the development of ulcers are still debated, poor results of nonoperative management to prevent ulcer recurrence justify surgical attempts at perforator ligation, in addition to ablation of superficial reflux. The endoscopic technique of perforator interruption has significantly fewer wound complications than the open technique and is the preferred method for ablation of medial perforating veins. Interruption of incompetent perforators with ablation of the superficial reflux, if present, effectively and durably decreases symptoms of CVI and rapidly heals ulcers. Ulcer recurrence following correction of perforator and superficial reflux in patients with post-thrombotic syndrome is much higher than in patients with primary valvular incompetence. A prospective randomized trial is needed to define the long-term benefits of interrupting incompetent perforators in all patients with advanced chronic venous disease and which patients with post-thrombotic syndrome should undergo perforator interruption.
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PMID:Endoscopic perforating vein surgery. 1041 Jun 94

The effect of venous hypertension on the state of activation of leucocytes has been investigated in patients with venous disease and control subjects. Leucocytes become 'trapped' in the circulation of the leg during periods of venous hypertension produced by sitting or standing. This is greater in the limbs of patients with chronic venous disease than controls. Studies of the plasma levels of neutrophil granule enzymes show that these are increased during periods of venous hypertension, suggesting that this causes activation of the neutrophils. Investigation of the leucocyte surface ligand CD11b shows that the more activated neutrophils and monocytes are sequestered during venous hypertension. Measurement of plasma levels of the soluble parts of the vascular (VCAM), intercellular (ICAM) and endothelial leucocyte (ELAM) adhesion molecules show that these are all elevated in patients with chronic venous disease compared to controls. Following 30 min of venous hypertension produced by standing, these levels are further increased. These data suggest that venous hypertension causes neutrophil and monocyte activation, which in turn causes injury to the endothelium. I believe that this may be the mechanism that initiates the pathological processes which lead to venous ulceration. It has recently been shown that the venotonic drug Daflon 500 mg (450 mg diosmin, 50 mg hesperidin, Servier, France) influences these processes. Surface expression of CD62L is reduced in neutrophils and monocytes, and plasma levels of soluble endothelial adhesion molecules are reduced. These observations may explain the anti-inflammatory effects of Daflon 500 mg.
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PMID:Neutrophil activation and mediators of inflammation in chronic venous insufficiency. 1047 48

Subfascial endoscopic perforator surgery (SEPS) is a new, minimally invasive technique performed in patients with advanced chronic venous insufficiency. The objective of the operation is to interrupt incompetent medial calf perforating veins to decrease venous reflux and reduce ambulatory venous hypertension in critical areas above the ankle where venous ulcers most frequently develop. Patients with stasis skin changes and healed or active venous ulcerations are potential candidates for the operation. Preoperative evaluation is performed with duplex scanning of the superficial, deep and perforator system, to diagnose both obstruction and valvular incompetence. Results of the North American SEPS Registry (NASEPS) as well as experience in several individual centers confirmed that the operation has significantly fewer wound complications than the classic open surgical techniques, and that rapid ulcer healing can be achieved. At the Mayo Clinic an ulcer recurrence rate of 12% was observed, with recurrence significantly more frequent in post-thrombotic limbs than in patients with primary venous valvular incompetence. The NASEPS Registry report confirmed a 2-year cumulative ulcer recurrence rate of 28%; ulcer recurrence was significantly more frequent in post-thrombotic limbs, especially in those with deep venous obstruction. SEPS is a new, low-risk, outpatient procedure that effectively decreases perforator reflux in patients with venous ulcerations, and should be added to our armamentarium to treat patients with advanced chronic venous disease. Long-term prospective and randomized studies are, however, still required to provide level I evidence of late efficacy.
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PMID:Subfascial endoscopic perforator vein surgery: indications and results. 1051 97

Until recently, studies dealing with veins have almost always been the neglected part of vascular research. Recent data show an increasing rate of venous disease, and increasing evidence supports a role for veins in systemic diseases. The authors discuss and comment on findings of recent studies on venous drug reactivity. Alterations in venous reactivity to alpha- and beta-adrenergic, NO-dependent, and other drugs have been shown in many genetically determined and acquired conditions, such as hypertension, smoking, and aging. In some of them, the changes of venous responsiveness are most likely secondary to another process, while in others the they seem to play a primary role in the development of systemic disease states. Studying the drug reactivity of the venous system more extensively provides useful information for clinicians and researchers and will no doubt help to further knowledge of the normal and pathologic processes of the vasculature.
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PMID:Alterations of venous drug reactivity in humans: acquired and genetic factors. 1082 52


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