Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stroke places a tremendous burden on health resources throughout the world. Improved detection and modification of risk factors could reduce the impact of this disease. Important non-modifiable risk factors for ischemic stroke include age, gender, ethnicity, and heredity. Modifiable risk factors include hypertension, cardiovascular disease, diabetes, hyperlipidemia, asymptomatic carotid stenosis, cigarette smoking, and alcohol abuse. Data from the Northern Manhattan Stroke Study provide new insights into these stroke risk factors. In this study, African-Americans and Hispanics had a greater incidence of stroke, with almost a twofold increase compared with Caucasians. The protective effect of physical activity and moderate alcohol consumption was confirmed and further established as modifiable risk factors. The independent effects of lipids, apolipoproteins, and lipoprotein were also clarified. High-density lipoprotein was shown to be protective against ischemic stroke (particularly atherosclerotic stroke subtypes). Conversely, lipoprotein-a increased the risk for stroke. The ratio of apolipoprotein b to apolipoprotein a-1 was shown to be associated with carotid atheroma. In addition, newer risk factors, including homocysteine and chronic infection (Chlamydia pneumoniae and periodontal disease), are being studied as predictors of ischemic stroke. With these recent advances in the understanding of risk factors, the ability to detect or modify the risk for ischemic stroke should lead to a substantial reduction in the number of people killed or disabled by stroke each year.
 ...
PMID:Newer risk factors for stroke. 1155 52

There is growing evidence that inflammatory processes may be involved in the development of atherosclerosis and its complications. Viral and bacterial pathogens have been implicated as possible causative factors in the pathogenesis of coronary artery disease (CAD) and restenosis after angioplasty. Antibiotic trials are now in progress to examine whether treatment of infection can prevent the complications of CAD. Atherosclerosis, the primary pathologic process in coronary artery disease (CAD), carotid artery disease, abdominal aortic aneurysm, and peripheral vascular disease, is no longer considered to be an obscure, slowly progressive, degenerative disease. Indeed, recent molecular studies on the atherosclerotic plaque have shown that the initiation, progression, and acute sequelae of atherosclerosis can be explained in part by a low-grade inflammatory process. Studies show that mediators of inflammation can be found at all stages of the life cycle of the atherosclerotic plaque. These include activated macrophages and lymphocytes, cytokines, growth factors, matrix degenerating proteinases, and tissue factor. It is hypothesized that risk factors such as hypertension, smoking, or elevated levels of low-density lipoprotein (LDL) cholesterol result in injury to the endothelial cell of the artery, and this injury initiates the inflammatory process. However, many patients with vascular disease do not have these established risk factors, and this observation has galvanized efforts to find new risk factors. Because inflammation is now considered to be an operative paradigm for atherosclerosis, it is not a major leap to the hypothesis that infectious agents, such as viral or bacterial, may play a role. Certainly this is not a new concept, and with the recent discovery that peptic ulcer disease, heretofore considered a disease of excess acid and reduced mucosal resistance, is caused by the ubiquitous bacterium Helicobacter pylori, interest in finding an infectious etiology for atherosclerosis has increased. Accordingly, the purpose of this discussion is to review in a historical manner the evidence that infectious agents-including herpes simplex virus (HSV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), Enterovirus (adenovirus, Coxsackie virus), Chlamydia pneumoniae, and H. pylori-may play a role in atherosclerosis and its manifestations, especially as they relate to CAD.
 ...
PMID:The role of infection in atherosclerosis and coronary artery disease: a new therapeutic target. 1172 77

There are conflicting reports of an association between Chlamydia pneumoniae (C. pneumoniae) infection and coronary artery disease (CAD); randomized trials of antibiotics for the secondary prevention of CAD are currently underway. Physicians may be tempted to believe that their choice of antibiotic class in treating any infection may alter the risk of CAD. Our objective was to determine if the use of antibiotics with antichlamydial activity in the general population reduces the risk of myocardial infarction. A healthcare claims database with 354,258 patients with continuous health and pharmacy coverage for at least 2 years between January 1, 1991 and December 31, 1997 was used for the analyses. Hazard ratios were derived from proportional hazards models with time-dependent covariates, relating antibiotic prescription to first claim related to incident first myocardial infarction during the observation period, adjusting for previous CAD, age, sex, diabetes, hypertension, hyperlipidemia, and chronic obstructive pulmonary disease. There were a total of 1,684,091 person-years of observation and 16,139 incident myocardial infarctions. The adjusted hazard ratios were 1.10 (95% confidence intervals [CI] 1.04 to 1.16) for macrolides, 1.20 (95% CI 1.13 to 1.26) for quinolones, 1.10 (95% CI 0.96 to 1.21) for cephalosporins, 1.00 (95% CI 0.96 to 1.06) for tetracyclines, 1.01 (95% CI 0.96 to 1.06) for penicillins, and 1.13 (95% CI 0.98 to 1.30) for trimetroprim-sulfamethoxazole. The hazard ratios for individual antibiotics with activity against C. pneumoniae within each group were similar. Use of antibiotics with activity against C. pneumoniae does not reduce the risk of myocardial infarction in the general population.
 ...
PMID:Relation of antibiotic use to risk of myocardial infarction in the general population. 1177 16

Infection with microorganisms such as Helicobacter pylori and Chlamydia pneumoniae has been associated with coronary heart disease (CAD) and hypertension (HT). Infection increases the release of pro-inflammatory cytokines, thus facilitating interactions that lead to vascular damage and other effects. We hypothesized that genetically determined differences in activity or responsiveness of cytokine(s) might contribute to HT. The interleukin-1 gene (IL1) cluster on chromosome 2q14 contains three related genes (IL1A, IL1B, and IL1RN) located within a 430-kb region. These encode IL-1alpha and IL-1beta, as well as their endogenous receptor antagonist, IL-1ra. The IL1RN gene has a penta-allelic 86-bp tandem repeat in intron 2. Allele IL1RN* 2 is associated with a wide range of chronic inflammatory and autoimmune conditions, and its combination with the -31T variant of an IL1B C(-31)T polymorphism constitutes a pro-inflammatory haplotype that leads to vigorous IL-1beta production. We therefore tested each of these polymorphisms for association with HT. Subjects were white Anglo-Celtic residents of Sydney, Australia. Frequencies of IL1B C(-31)T genotypes CC, CT, and TT were 0.50, 0.40, and 0.10 in normotensive (NT) and 0.46, 0.46, and 0.08 in HT, respectively (chi(2) = 1.2, P = 0.55). T allele frequency in NT (0.30) was similar to that in HT (0.31). For the IL1RN variant, frequencies of alleles IL1RN* 1 and * 2 and combined minor alleles * 3, * 4, and * 5 were 0.61, 0.36, and 0.03 in NT and 0.54, 0.36, and 0.10 in HT, respectively (chi(2) = 11, P = 0.004). In conclusion, no association of the IL1B C(- 31)T with HT was found, whereas combined frequency of the minor alleles of the IL1RN polymorphism was increased in the HT cohort studied.
 ...
PMID:Association analysis of polymorphisms at the interleukin-1 locus in essential hypertension. 1184 Apr 88

Elevated levels of homocyst(e)ine and infection by Chlamydia pneumoniae have been hypothesized individually to play a role in coronary artery disease (CAD), but the mechanisms are unclear. Data on a possible association are not available. We investigated the correlation between IgG antibody titers against C. pneumoniae and fasting plasma homocyst(e)ine in 234 consecutive male patients with CAD. Chlamydial antibodies to a recombinant genus-specific lipopolysaccharide (LPS) were measured with ELISA. Total homocyst(e)ine (tHcy) concentrations were measured by high-performance liquid chromatography (HPLC). Thirty-seven subjects were classified hyperhomocyst(e)inemic (fasting homocyst(e)ine>14 micromol/l, group A), and 197 subjects were below cut-off (tHcy<14 micromol/l, group B). Prevalence of IgG seropositivity against C. pneumoniae was significantly higher in group A (68%) as compared to group B (39%, P=0.002). Antibody titers were also significantly higher in hyperhomocyst(e)inemic subjects than in cases with low homocyst(e)ine levels (P=0.002). Overall titers correlated significantly with tHcy levels (r(2)=0.222, P=0.001). Hyperhomocyst(e)inemia was associated with arterial hypertension (P=0.003), intake of lipid lowering drugs (P=0.022) and quite not with low folate concentration (P=0.052). No association was seen for IgG seropositivity or homocyst(e)ine and age, body mass index, smoking, diabetes, vitamin B(6) and B(12), cholesterol and triglycerides. These data indicate an association between elevated plasma homocyst(e)ine concentrations and chlamydial IgG antibody titers in patients with CAD.
 ...
PMID:Hyperhomocyst(e)inemia and Chlamydia pneumoniae IgG seropositivity in patients with coronary artery disease. 1253 57

Atherogenesis is a disease of middle-sized and large-caliber blood vessels that can be divided into three major phases. The initial lesions of early atherosclerosis are characterized by the adhesion and subendothelial emigration of blood-borne monocytes, which differentiate into macrophages and provide the morphologic basis for the formation of foam cells and fatty streak lesions. These lesions are found in most children and teenagers in industrialized nations. The next key event in atherogenesis is the proliferation of smooth muscle cells within the intima and media, resulting in the gradual compromise of the vessel lumen. Myofibroblastic cells also contribute to lesion growth through the production of excessive amounts of extracellular matrix. Such lesions are clinically silent unless progression to the next phase continues: the lesions degenerate, forming a mostly necrotic "lipid core" consisting of extracellular lipid, cholesterol crystals, inflammatory cells and necrotic debris. A fibrous cap is formed which prevents the interaction of blood cells, particularly of platelets with the highly proaggregatory material found in the lipid core. However, continuous inflammatory activity and/or heightened mechanical stress (i.e., in hypertension) tends to weaken the fibrous caps. Eventually, plaque rupture ensues, platelets aggregate, and the lesions become clinically manifest in such dramatic events as myocardial infarction, stroke, or mesenteric ischemia. Research into lesion formation and progression is limited by the fact that lesions develop in silence over many decades and that animal models only incompletely model the situation in humans. Most currently debated concepts accept the "response to injury" hypothesis formulated by the late Russell Ross and the multi-factorial nature of atherogenesis. The discussion today circles around the relative contributions of low density lipoproteins (oxidized or enzymatically modified LDL?), the immune response (adaptive or innate?), infectious agents (CMV, Chlamydia pneumoniae?), and/or hereditary factors, to name only a few of the most widely debated concepts. Irrespective of the outcome of this pathomechanistic discussion, the knowledge of established risk factors (hypercholesterolemia, hypertension, diabetes, smoking, etc.) and protective interventions (lifestyle changes, physical exercise, "healthy" diets, effective dietary and pharmacologic control of hyperglycemia, blood pressure or hyperlipidemia) has helped to define atherosclerosis as a "new entity" that has little to do with the archaic concept of a "degenerative" vessel disease. The new concept takes us into the responsibility--puts us in charge of our own and our patients' cardiovascular risk--whether we like it or not. The smoking obese doctor no longer fits into the modern medical landscape.
 ...
PMID:[Atherosclerosis--progression by nonspecific activation of the immune system]. 1197 79

The established risk factors for atherosclerosis such as hypertension, smoking, diabetes mellitus, hyperlipidemia, and hyperhomocysteinemia do not explain clinical and epidemiological features of coronary heart disease (CHD). The role of infectious disease as a CHD risk factor may partly explain these features. Chronic infection with various microorganisms, particularly, Chlamydia pneumoniae, Cytomegalovirus (CMV) and Helicobacter pylori may play a role in etiological factors, linking inflammation and atherogenesis. Results from epidemiological studies, pathology of atherosclerotic plaques, animal studies, molecular biology and clinical antibiotic trials indicated a positive association between C. pneumoniae infection and CHD. Chronic infection might also influence preexisting plaque by enhancing T cell activation, which participate in destabilization of intimal cap. However, the exact nature of pathophysiological link between the organisms and CHD remains to be elucidated. Future antibiotic interventional studies may help to further clarify the role of chronic infection and inflammation in CHD.
 ...
PMID:Chronic infections and atherosclerosis. 1200 6

Pathogenesis of the atherosclerotic process is deemed as multifactorial. To the most important risk factors, besides certain family predisposition, there belongs hypercholesterolemia, arterial hypertension, obesity, diabetes mellitus, smoking and others. In the last years there are more and more data about the role of inflammation and infection in the whole development of atherosclerosis. The witness for this hypothesis is the findings of high parameters of inflammation in involved vessels as well as in the blood of atherosclerosis suffering persons. Opinions about the inflammation theory appear from the 90th. Local sterile inflammation in the subendotelium of the middle and big arteries has been proved to consist of specific immune reaction (activation of the T-lymphocytes) as well as nonspecific characteristic by elevated monocytes in the artery wall during the whole process of atherogenesis. Inflammation in the plaque can trigger and hold several factors engaged in the atherosclerotic process, such as oxidized LDL cholesterol, elevated production of various superoxides, activated macrophages, activated T-lymphocytes, cytokines (IL-1, IL-6, interferon gamma) and lipoprotein Lp (a). In this inflammation process levels of CRP (acute phase protein), fibrinogen and erythrocyte sedimentation are elevated as a reaction of the organism to nonspecific chronic infections. Because of this it is thought that elevated fibrinogen and erythrocyte sedimentation are markers of the cardiovascular risk. Some papers deal with antiinflammatory effects of statins, because these lower CRP levels so they also lower atherosclerotic risk through not only lowering of cholesterol levels. Also asprine, as an antiinflammation agent, changing the CRP levels, would be of benefit for patients with vascular disease because its antiaggregation and antiinflammatory effects. ACE inhibitors are also antiinflamatory through blocking of tissue production of angiotensin II (artery wall and atherosclerotic plaque). Enzymatic inhibitors changing angiotensin can also have a partial antiinflammatory effect. The infection theory is supported also by tracing of some microorganisms in the atherosclerotic plaque or in the blood, as e.g. Helicobacter pylori or Chlamydia pneumoniae; to the autoimmune origin is indicated the presence of the specific immunity reaction against heat shock proteins (HSP) or oxidized LDL. This infection theory offers new therapy possibilities. Therefore eradication for example by antibiotics can lead to stabilization of the atherosclerotic plaque with positive consequences, as it was discovered by many studies.
 ...
PMID:[The role of infection and inflammation in the pathogenesis of atherosclerosis]. 1219 10

It is known that local and systemic inflammatory processes play an important role in the genesis and development of atheroclerotic lesions and in the pathophysiology of acute coronary syndromes. This hypothesis is supported by findings of elevated parameters of the "inflammatory" reaction in the affected blood vessels but also in the blood of atherosclerotic patients. Known risk factors do not explain quite satisfactorily epidemiological cardiovascular phenomena and different manifestations of coronary heart disease. It is very probable that also Chlamydia pneumoniae is a risk factor. This assumption is based on evaluation of seroepidemiological data, examination of atherosclerotic plaques not only in humans but also in animal models with chlamydial infection. Based on retrospective and prospective evaluation of case-records the authors analyzed the incidence of cardiovascular complications in 83 patients with acute myocardial infarction (AIM), incl. 51 patients (31 men and 20 women, mean age 64.4 +/- 3.4 years who had a non-specific inflammation and chlamydial infection, and 32 patients (24 men and 8 women, mean age 64.7 +/- 3.6 years) who had chlamydial infections but no non-specific inflammation (in the blood). These patients were selected from all patients hospitalized during 1998-2001. When diagnosing acute myocardial infarction we applied WHO criteria, and the presence of at least two of three criteria was necessary: a history of prolonged (more than 20 min). stenocardia, electrocardiographic changes typical for ischaemia and/or necrosis and elevation of myocardial enzymes in serum, Non-specific inflammatory activity was present in patients (i.e. positive) if the following laboratory parameters were recorded: C-reactive protein > 5 mg/l assessed by the radial immunodiffusion method; fibrinogen > 4 mg/l assessed by the coagulation method according to Claus; leukocytes > 9.6 x 10(3)/microliter, leukocytes were counted automatically in a Coulter chamber; lymphocytes > 3.4 x 10(3)/microliter. Red cell sedimentation rate > 20 mm/hour. The activity was evaluated as positive when all parameters were elevated. The presence of chronic infection with Chlamydia pneumoniae was assessed qualitatively by antibody positivity (IgG) in serum using the microimmunoflurescent method (using a set from Labsystems Co.). The incidence of associated risk factors (obesity, smoking, diabetes, hyperlipidaemia and hypertension) is higher in the sub-group of patients with Chlamydia infections without inflammation, however, the difference is not statistically significant. The incidence of cardiovascular attacks was higher in the sub-group of patients with chlamydial infection and concurrent inflammation as compared with the sub-group of patients with chlamydial infection without inflammation. In case of re-infarction of the myocardium, a sudden cerebrovascular attack, death and arrhythmia the difference was statistically significant, while in case of cardiac failure and cardiogenic shock the difference was not significant. Patients with acute myocardial infarction with chlamydial infection and a concurrent non-specific inflammation had to be treated more often by combined (i.e. more intense) treatment, thrombolytic treatment, PTCA and surgery (bypass) of the coronary vessels as compared with patients with Chlamydia infections but without inflammation. The authors assume therefore that not only different risk factors but also the effect of non-specific inflammation and Chlamydia infection contribute towards the increased number of cardiovascular postinfarction complications. Therefore a therapeutic approach involving eradication of infection and suppression of the inflammatory reaction should be considered.
 ...
PMID:[Effect of chronic Chlamydia infection with non-specific inflammation on cardiovascular complications in acute myocardial infarct]. 1272 71

Current topics and new developments in risk factors for ischemic stroke were reviewed. Hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, cigarrette smoking, and heavy alcohol drinking have been established as being common treatable risk factors for stroke. Recent studies have clarified that homocysteine, various cardiac sources of embolism such as patent foramen ovale, antiphopholipid antibodies, lipoprotein (Lp) abnormalities including Lp(a) and remnant-like particle, insulin resistance or hyperinsulinemia, infectious diseases such as Chlamydia Pneumoniae, and CRP are additional risk factors for stroke. In addition, genetic studies using single nucleotide polymorphisms have suggested that many gene polymorphisms are significant risk factors for certain subpopulations of stroke, which is recognized to be a polygenic disease. Management of these risk factors is crucial for primary prevention of stroke, which is the leading cause of death or disability all over the developed countries.
 ...
PMID:[Risk factors for cerebral infarction: current topics and new developments]. 1278 67


<< Previous 1 2 3 4 5 6 7 Next >>