ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Key WordsEditorials, heart diseases, heart block, myocardium.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

Key WordsEditorials, heart rate, exercise.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundTo explore pathophysiological mechanisms of cigarette smoking involved in atherogenesis, we compared adhesiveness of isolated blood monocytes with endothelium and plasma levels of the aqueous phase antioxidant vitamin C in nonsmokers and smokers before and after supplementation, using a novel monocyte adhesion assay with fixed human endothelial cells.Methods and ResultsMonocyte adhesion to unstimulated human umbilical vein endothelial cells ranged from 0.17% to 0.51% in the nonsmoker group (0.37 plus/minus 0.09%, mean plus/minus SD, n = 13). In smokers with a 1 to 2 packs per day consumption, monocyte adhesion was increased to 0.71 plus/minus 0.17% (mean plus/minus SD, n = 10, P < .001), ranging from 0.46% to 0.99%. Increased adhesiveness was mediated by the integrin CD11b/CD18, as shown by inhibition with a monoclonal antibody to CD11b but not associated with altered CD11b surface expression. Plasma vitamin C levels were reduced in smokers (48.2 plus/minus 14.1 micro mol/L) versus nonsmokers (67.7 plus/minus 17.6 micro mol/L; P < .025), while no significant differences were found in retinol, vitamin E, or beta-carotene levels. This confirms that the radical scavenger vitamin C reacts sensitively to oxidative stress induced by cigarette smoke in human plasma. Consistently, dietary supplementation with vitamin C (2 g per day) for 10 days raised plasma levels to 82.6 plus/minus 11.0 micro mol/L (n = 10, P < .001) in smokers and decreased monocyte adhesion to values found in nonsmokers (0.38 plus/minus 0.18%, P < .001). In contrast, vitamin C intake did not affect monocyte adhesiveness in nonsmokers (0.37 plus/minus 0.14%, n = 6) despite increasing plasma levels to 82.9 plus/minus 11.8 micro mol/L.ConclusionsOur data show that cigarette smoking increases CD11b-dependent monocyte adhesiveness in humans. Restoring reduced plasma vitamin C concentrations in smokers by oral supplementation decreased monocyte adhesion to values found in nonsmokers. (Circulation. 1996;93:1488-1492.)Key Wordssmoking, antioxidants, endothelium.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundVascular endothelial growth factor (VEGF) is an endothelial cell-specific growth factor and a regulator of physiological and pathological angiogenesis. Four different proteins are produced by alternative splicing of a unique transcript generated from a single-copy gene. Knowledge of the chromosomal location of the VEGF gene would help in determining a linkage to any known human congenital syndrome and/or to known chromosomal rearrangements in tumors.Methods and ResultsA human chromosome mapping panel was used to assign the VEGF gene to human chromosomes by polymerase chain reaction using VEGF-specific oligonucleotide primers. Amplified DNA fragments were fractionated on a 1% agarose gel. A single band of the expected size was obtained only from the DNA of those hybrid cell lines that contained the human chromosome 6. Three YAC clones containing the VEGF gene were obtained by screening the ICI Diagnostics library. In situ hybridization was then used to locate the VEGF gene in the 6p21.3 region.ConclusionsThe location of the VEGF gene in the 6p21.3 region is a potential starting point for a linkage study. In addition, the isolation of YAC clones containing the VEGF gene will contribute to the construction of the physical map of this chromosomal region. (Circulation. 1996;93:1493-1495.)Key Wordsangiogenesis, growth substances, genes.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundPrognosis after myocardial infarction (MI) is influenced by the presence of post-MI ischemia and possibly the patency of the infarct-related artery. The purpose of this study was to compare long-term outcome (reinfarction and death) in patients with open versus closed coronary arteries after percutaneous transluminal coronary angioplasty performed for MI complicated by persistent ischemia.Methods and ResultsBetween 1981 and 1989, 505 patients underwent percutaneous transluminal coronary angioplasty for post-MI ischemia at the Deaconess Hospital. Long-term incidence (mean follow-up, 34 months) of death, nonfatal reinfarction, repeated coronary angioplasty, and coronary bypass surgery was determined for 479 patients and then compared on the basis of the status of the artery, open versus closed, at the end of angioplasty. The 5-year Kaplan-Meier actuarial mortality rate was 4.9% for 456 patients with open infarct-related arteries and 19.4% for 23 patients with closed infarct-related arteries (P = .0008). Multivariate Cox proportional hazards analyses controlling for age, sex, number of diseased vessels, type and location of MI, and year of coronary angioplasty revealed a hazard ratio for death for closed compared with open arteries of 6.1 (95% CI, 1.8 to 20.0). Among patients with ejection fractions < 50%, a closed artery was associated with a higher mortality (P = .0014) compared with patients with open arteries. The status of the artery was not associated with a difference in mortality in patients with ejection fractions greater or equal to 50%.ConclusionsAn open artery after coronary angioplasty for post-MI ischemia is associated with significantly lower long-term mortality, particularly in patients with ejection fractions < 50%. (Circulation. 1996;93:1496-1501.)Key Wordsangioplasty, ischemia, mortality, myocardial infarction.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundThe noninvasive measurement of absolute epicardial coronary arterial flow and flow reserve would be useful in the evaluation of patients with coronary circulatory disorders. Phase-contrast magnetic resonance imaging (PC-MRI) has been used to measure coronary arterial flow in animals, but its accuracy in humans is unknown.Methods and ResultsTwelve subjects (7 men, 5 women; age, 44 to 67 years) underwent PC-MRI measurements of flow in the left anterior descending coronary artery or one of its diagonal branches at rest and after administration of adenosine (140 micro gram (times) kg sup -1 (times) min sup -1 IV). Immediately thereafter, intracoronary Doppler velocity (IDV) and flow measurements were made during cardiac catheterization at rest and after intravenous administration of adenosine. For the 12 patients, the correlation between MRI and invasive measurements of coronary arterial flow and coronary arterial flow reserve was excellent: coronary flowMRI(mL/min) = 0.85 x coronary flowIDV(mL/min) + 17 (mL/min), r = .89, and coronary flow reserveMRI= 0.79x coronary velocity reserveIDV+ 0.34, r = .89. For the range of coronary arterial flows (18 to 161 mL/min) measured by MRI, the limit of agreement between MRI and catheterization measurements of flow was -13 plus/minus 30 mL/min; for the range of coronary reserves (0.7 to 3.7) measured by MRI, the limit of agreement between the two techniques was 0.1 plus/minus 0.4.ConclusionsCine velocity-encoded PC-MRI can noninvasively measure absolute coronary arterial flow in the left anterior descending artery in humans. PC-MRI can detect pharmacologically induced changes in coronary arterial flow and can reliably distinguish between those subjects with normal and abnormal coronary artery flow reserve. (Circulation. 1996;93:1502-1508.)Key Wordsmagnetic resonance imaging, coronary disease, regional blood flow.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundLeft ventricular (LV) diastolic dysfunction is common in heart failure and is an important predictor of prognosis and mortality. Less attention has been paid to right ventricular (RV) diastolic function. In this study, we compared RV diastolic function in a large cohort of patients with heart failure (HF) with two groups: patients with pulmonary hypertension and normal LV function (the PHT group) and normal subjects.Methods and Results40 mm Hg), and 40 normal subjects. A subset was matched for age and heart rate. The results showed a high prevalence of RV diastolic abnormalities: HF patients had lower tricuspid E-A ratios, lower peak E-wave velocity, and prolonged RV isovolumic relaxation time (all P < .0001). Tricuspid E-wave deceleration time was significantly shorter only in those who had an LV restrictive filling pattern. The PHT group had similar findings. Compared with a normal range, more than half of the patients had lower tricuspid E-A ratios (HF, 55%; PHT, 69%), and 61% of HF and 58% of PHT patients had a prolonged RV isovolumic relaxation time. In the PHT group, RV diastolic parameters (E-wave deceleration time, E-A ratio, and isovolumic relaxation time) correlated significantly with pulmonary artery systolic pressure (P < .05). In the HF group, however, only tricuspid E-wave deceleration time correlated significantly with pulmonary artery systolic pressure, and HF patients with normal pulmonary artery systolic pressures had significantly lower tricuspid E-A ratios and prolonged RV isovolumic relaxation times compared with normal subjects. A close correlation existed between individual RV and LV diastolic parameters, suggesting that LV diastolic dysfunction may directly affect RV function, but there was no relation between LV size or systolic function and RV diastolic dysfunction.ConclusionsRV diastolic function is frequently abnormal in HF patients, and this is not related to elevated pulmonary artery systolic pressure alone, although high pulmonary artery pressure by itself also is associated with impaired RV diastolic function. Assessment of the role of right ventricular diastolic function in determining the symptoms and prognosis of heart failure is warranted. (Circulation. 1996;93:1509-1514.)Key Wordsventricles, diastole, heart failure.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID

摘要:

BackgroundCongestive heart failure is associated with blood volume expansion caused by stimulation of the renin-aldosterone system and arginine vasopressin. The use of left ventricular assist devices as bridges to heart transplantation has improved the survival of patients during this critical period. In studying heart failure physiology on support devices, we hypothesized that improvement of cardiac function by a left ventricular assist device is associated with normalization of volume load secondary to normalization of its regulatory substances.Methods and ResultsWe studied 15 patients (13 men, 2 women; age, 51 plus/minus 8 years) with end-stage heart failure who were cardiac transplant candidates eligible for HeartMate implantation. We measured plasma volume and plasma levels of atrial natriuretic peptide, aldosterone, renin, and arginine vasopressin sequentially before HeartMate implantation (baseline), after HeartMate implantation (weeks 4 and 8), and after transplantation. Baseline plasma volume was 123 plus/minus 20% of normal; it was 122 plus/minus 22% at week 4 and decreased to 115 plus/minus 14% at week 8. Atrial natriuretic peptide was 359 plus/minus 380 pg/mL at baseline, 245 plus/minus 175 pg/mL at week 4, and 151 plus/minus 66 pg/mL at week 8. Plasma aldosterone fell from 68 plus/minus 59 ng/dL at baseline to 17 plus/minus 16 ng/dL at week 4 (P < .05 versus baseline) and was 32 plus/minus 50 ng/dL at week 8. Plasma renin activity decreased from 80 plus/minus 88 ng/dL at baseline to 11 plus/minus 12 ng/dL at week 4 and was 16 plus/minus 38 ng/dL at week 8 (both P < .05 versus baseline). Arginine vasopressin fell from 5.0 plus/minus 4.8 fmol/mL at baseline to 1.1 plus/minus 0.7 fmol/mL at week 4 and 1.2 plus/minus 0.8 fmol/mL at week 8 (both P < .05 versus baseline).ConclusionsThe reduction of plasma renin activity, plasma aldosterone, and arginine vasopressin occurred earlier than the reduction of plasma volume and atrial natriuretic peptide after HeartMate implantation, possibly because of decreased pulmonary congestion and improved renal perfusion. The reduction of atrial natriuretic peptide cannot be responsible for the lack of adequate decrease of plasma volume; its reduction can be taken as a marker of improved cardiac pump function and decreased atrial stretch. (Circulation. 1996;93:1515-1519.)Key Wordsplasma, heart-assist device, heart failure.

ISSN:0009-7322    

出版商:OVID    

年代:1996

数据来源: OVID