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Biomedical subjects

S D Eilen

Publications and source records attributed to S D Eilen.

8 recordsLinked to original sources
PubMed1986

Alterations in regional myocardial blood flow after nitroprusside and nitroglycerin in patients with and without significant coronary artery disease.

To evaluate vasodilator-induced redistribution of regional myocardial blood flow, intravenous sodium nitroprusside and nitroglycerin were administered in doses producing matched reductions (15%) in mean arterial pressure at constant heart rate. Anterior left ventricular great cardiac vein blood flow (thermodilution) was measured in 14 patients without angiographic anterior collateral supply. Global coronary sinus blood flow remained constant with both nitroprusside and nitroglycerin administration, despite significant reductions in mean arterial pressure. However, nitroglycerin reduced great vein flow by 25 +/- 17% and nitroprusside by 10 +/- 16% (p less than 0.01). Subgroup analysis indicated that the nitroglycerin-nitroprusside regional blood flow differences were more pronounced in patients without significant left anterior descending coronary artery narrowing. Neither vasodilator produced significant differences in arterial-coronary sinus oxygen or lactate contents, calculated myocardial oxygen consumption, left ventricular dP/dt, or electrocardiographic or clinical signs of myocardial ischemia. Despite qualitatively similar hemodynamic effects, comparisons of vasodilator-induced relative reductions in normally supplied anterior left ventricular regional coronary blood flow suggest a mechanism of the reported beneficial effects of nitroglycerin on potentially ischemic myocardial regions.

Adult↗
PubMed1985

Regional coronary vasoconstriction after combined beta-adrenergic and calcium channel blockade in patients with coronary artery disease.

The beta-adrenergic and calcium channel blocking drugs, which individually and combined have proven efficacious in the treatment of angina pectoris, appear to have opposing effects on coronary artery vasomotion. Previous studies have shown that beta-adrenergic blockade may potentiate and calcium channel blockade reverse coronary vasoconstriction during adrenergic cold stimulation in patients with coronary artery disease. To assess the coronary hemodynamic effects of combined drug therapy, thermodilution coronary sinus and great cardiac vein flow and mean arterial pressure were measured during serial cold pressor testing, both before and after 0.1 mg/kg of intravenous propranolol and again after the addition of 10 mg of sublingual nifedipine in 21 patients (9 without [group A1] and 12 with [group A2] greater than 50% narrowing of the left anterior descending coronary artery). In an additional 15 patients (6 patients without [group B1] and 9 with [group B2] left anterior descending artery stenosis), serial cold pressor testing was performed reversing the drug order. Despite significant increases in mean arterial pressure (p less than 0.01) during cold pressor testing, coronary sinus resistance responses after propranolol plus nifedipine were not statistically significant for any group. However, regional coronary resistance responses differed between patients with and without left anterior descending artery stenosis. In group A1, great cardiac vein resistance was unchanged after propranolol plus nifedipine. In group A2, great cardiac vein flow decreased significantly after propranolol plus nifedipine from 8 +/- 17 to -4 +/- 12% (p less than 0.01 versus control), and great cardiac vein resistance increased from 4 +/- 21 to 15 +/- 19% (p less than 0.01 versus control). A similar significant response was observed for groups B1 and B2. Regional coronary vasoconstriction during adrenergic stimulation after combined drug therapy was only observed in patients with significant left anterior descending artery stenosis. These data suggest that in some patients with severe coronary artery disease, combined beta-adrenergic and calcium channel blockade modified regional coronary responses to adrenergic stimulation with an inhomogeneous distribution of blood flow to potentially ischemic regions without affecting total coronary blood flow. These data also imply that an improvement in anginal symptoms after combined drug therapy may be due primarily to mechanisms that reduce myocardial oxygen demand rather than to improved myocardial oxygen supply.

Adrenergic beta-Antagonists↗
PubMed1983

Chemiluminescence and superoxide anion production by leukocytes from diabetic patients.

Stimulated neutrophils exhibit a burst of oxidative metabolism which results in the formation of superoxide anion and other oxygen species that participate in bacterial killing. Chemiluminescence is also produced and is a sensitive measure of oxidative metabolism and correlates well with antimicrobial activity. Since infection is an important cause of morbidity and mortality in diabetic patients we examined chemiluminescence and superoxide production by leukocytes from diabetics in the resting state and in response to a soluble (phorbol myristate acetate) and to a particulate stimulus (opsonized zymosan). No significant difference in the resting chemiluminescence was observed. However, the resting superoxide anion production by patients' leukocytes was significantly higher in autologous serum; when patients' leukocytes were placed in normal serum, a significant reduction in the resting superoxide anion production was observed. Using phorbol myristate acetate as a stimulus, leukocytes from diabetic patients had a markedly reduced chemiluminescence response [controls 388 +/- 48, n = 22, patient 220 +/- 37, peak cpm X 10(3)/10(6)P leukocytes, n = 22, (P less than 0.01)] and reduced superoxide anion response [controls 30.1 +/- 3.8, n = 16, patients 13.3 +/- 2.6 nmol/15 min/10(6)P leukocytes, n = 16 (P less than 0.001)]. Significantly reduced chemiluminescence response (P less than 0.05) and superoxide production (P less than 0.05) by leukocytes from diabetic patients were also observed using opsonized zymosan as a stimulus. No significant effects on chemiluminescence or superoxide response to phorbol myristate acetate were observed with cross-incubation studies in which patients' leukocytes were placed in normal serum or control leukocytes in patient serum. In vitro addition of insulin (25 microU; 100 microU/ml) had no significant effect on patient cell response; similarly increasing the glucose concentration from 100 mg/dl to 200 mg/dl and 400 mg/dl had no significant effect on control cell response. Glucagon in a lower concentration (200 pg/ml) had no significant effect; only at a higher concentration (400 pg/ml), it caused an inhibition of the phorbol stimulated chemiluminescence and superoxide response of control leukocytes. These results show an impaired oxidative burst by leukocytes from diabetic patients which may contribute to impaired bacterial killing and may explain, in part, the morbidity and mortality in diabetic patients suffering from infection.

Adult↗
PubMed1983

The effect of intravenous clonidine hydrochloride on the isolated forearm venous segment in heart failure.

The effects of intravenous (IV) clonidine (150 micrograms) on the isolated forearm venous segment of ten patients with heart failure were studied. Clonidine reduced pressure in the isolated venous segment of all patients (12.8 +/- 2.1 to 10.6 +/- 1.4 mm Hg, p less than 0.005). In addition, IV clonidine decreased the pressor response to mental arithmetic (2.9 +/- 0.3 mm Hg to 1.8 +/- 0.3 mm Hg, p less than 0.05), while the pressor response to deep breath was slightly enhanced (4.5 +/- 0.8 mm Hg to 6.1 +/- 0.7 mm Hg, p less than 0.05).

Adult↗
PubMed1983

Accuracy of precordial palpation for detecting increased left ventricular volume.

Objective data on the reliability of precordial palpation in detecting left ventricular enlargement are scarce. Therefore, we evaluated 41 patients by physical examination and two-dimensional echocardiography to determine the relation between the location of the apex and left ventricular end-diastolic volume. An apical impulse lateral to the mid-clavicular line or greater than 10 cm from the mid-sternal line was sensitive but not specific as an indicator of left ventricular enlargement. In patients without left ventricular hypertrophy, an apical diameter greater than 3 cm in the left lateral decubitus was sensitive (92%) and specific (91%) for an enlarged left ventricle. The positive and negative predictive values were 86% and 95% respectively. Therefore, the location of the apical impulse in relation to the mid-clavicular line or the mid-sternal line is not a reliable indicator of increased left ventricular end-diastolic volume. However, an apical impulse greater than 3 cm may be an accurate indicator of left ventricular enlargement.

Adult↗