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Biomedical subjects

D B Glamann

Publications and source records attributed to D B Glamann.

24 records · Page 2Linked to original sources
PubMed1992

Are contraction and relaxation coupled in patients with and without congestive heart failure?

BACKGROUND: Although changes in contractility are often accompanied by changes in relaxation, a mathematical model of ventricular coupling has not been described. A model we examined suggests a hyperbolic relation between measurements of contraction and relaxation. We thus tested the hypothesis that relatively load-independent measurements of contractility (end-systolic elastance [Ees]) and relaxation (the slope of the tau-to-end-systolic pressure relation [R]) were coupled. METHODS AND RESULTS: To establish the validity of the model, an assessment of Ees and R was made in 30 subjects who underwent sequential digital ventriculography and micromanometer pressure measurements during atrial pacing (93 +/- 10 min-1) before and after graded doses of nitroprusside. To establish if a cyclic AMP (cAMP)-mediated intervention alters coupling, seven of the 30 subjects were studied before and after 3 months of beta-blockade. To determine if a non-cAMP-mediated intervention alters coupling, 12 other patients were studied before and after deslanoside. Nonlinear regression analysis for the initial 30 patients suggested a hyperbolic relation: (Ees) (R) = 1.05 (r = 0.79, p less than 0.001) with an inflection point near Ees = 1.02 mm Hg/ml. Thus, with normal or near-normal contractility, relaxation is normal and not load dependent (R is close to 0). With systolic dysfunction, relaxation becomes very afterload dependent and so must be normalized for load. After long-term beta-blockade in patients with severe left ventricular dysfunction, small improvements in contractility (elastance) occurred with larger changes in relaxation, but the curve describing the relation was not displaced. Acute administration of deslanoside resulted in a large increase in elastance and a smaller change in relaxation but did not alter coupling. However, the magnitude of the change in R was dependent on the predrug R value. CONCLUSIONS: These data suggest contraction and relaxation may be physiologically coupled with relaxation relatively preserved in early heart failure and more rapid deterioration in relaxation as elastance falls under 1.02 mm Hg/ml. Both beta-blockers (which may act through cAMP) and digitalis (which is cAMP independent) improve contraction and relaxation, but both mechanisms appear to maintain coupling. The hyperbolic relation between contraction and relaxation may have important implications regarding therapeutic response and selection of patients for clinical trials in heart failure.

Adrenergic beta-Antagonists↗
PubMed1992

Utility of various radionuclide techniques for distinguishing ischemic from nonischemic dilated cardiomyopathy.

BACKGROUND: Clinically, ischemic and nonischemic (idiopathic) dilated cardiomyopathy may be difficult to distinguish. Radionuclide ventriculography and exercise testing with thallium-201 scintigraphy are often used in an attempt to differentiate them noninvasively. With these techniques, the presence of (1) left ventricular (LV) regional asynergy, (2) depressed LV systolic function with normal right ventricular function, and/or (3) thallium-201 perfusion abnormalities traditionally has been regarded as evidence of ischemic heart disease. We assessed the incidence with which these abnormalities occur in patients with nonischemic-dilated cardiomyopathy. METHODS: Seventy-six patients (45 men, 31 women, aged 18 to 75 years) with invasively proven nonischemic-dilated cardiomyopathy underwent radionuclide ventriculography (n = 75) and provocative thallium-201 perfusion imaging (n = 17). RESULTS: Regional LV wall motion abnormalities were noted in 48% of patients, and 54% had LV systolic dysfunction without concomitant right ventricular dysfunction. Reversible and/or fixed exercise-induced thallium-201 perfusion abnormalities occurred in 94% of the patients studied. CONCLUSIONS: Radionuclide ventriculography and exercise testing with thallium perfusion imaging cannot be used reliably to differentiate ischemic from nonischemic dilated cardiomyopathy, since many patients with the latter have radionuclide evidence of LV segmental wall motion abnormalities, selective LV systolic dysfunction, and segmental perfusion abnormalities.

Adolescent↗
PubMed1991

Beneficial effect of long-term beta blockade after acute myocardial infarction in patients without anterograde flow in the infarct artery.

Previous studies have shown that long-term survival after acute myocardial infarction (AMI) is improved by beta-adrenergic blockade and anterograde flow in the infarct artery. This study was done to assess the influence of beta blockade on mortality in survivors of AMI without anterograde flow. Over 9.5 years, 113 subjects (87 men and 26 women, aged 26 to 66 years) with AMI and no anterograde flow in the infarct artery and no disease of the other arteries were medically treated for 48 +/- 28 (mean +/- standard deviation) months. Forty-six patients received long-term beta blockade (group I), whereas 67 did not (group II). The groups were similar in age, sex, cardioactive medications, left ventricular performance and infarct artery. Of the 46 group I subjects, 1 (2%) died of cardiac causes; in contrast, 20 (30%) of the group II patients died of cardiac causes (p = 0.007 compared with group I). Thus, in survivors of AMI without anterograde flow in the infarct artery, mortality is markedly reduced by long-term beta blockade.

Adrenergic beta-Antagonists↗
PubMed1991

Gonococcal endocarditis: twenty-five year experience.

Gonococcal endocarditis is a devastating albeit rare complication of disseminated gonorrhea. It virtually disappeared as a disease entity with the advent of antibiotic therapy. Recently, it has reappeared with surprisingly high frequency for unclear reasons. Since 1983, the authors have observed six episodes of this disease in five patients, the largest series reported to date. It is predominantly a disease of young people without underlying valvular heart disease. Characteristic clinical features include a high frequency of congestive heart failure and nephritis and a proclivity for aortic valve involvement, commonly with associated ring abscess, and large vegetations. Genitourinary symptoms, arthralgias, and rash are uncommon. Previously undescribed features include involvement of all four valves simultaneously, recurrence on an aortic valve prosthesis, and a high frequency of terminal complement deficiencies. Precipitous hemodynamic deterioration despite appropriate therapy is not uncommon, and overall mortality rate remains an alarming 19%.

Adult↗
PubMedDate not supplied

Collection and handling of clinical blood samples to assure the accurate measurement of cocaine concentration.

The measurement of serum cocaine concentration is difficult because it is rapidly metabolized in vivo and in vitro. Previous investigators have used sodium fluoride (0.5-3.0%) in an attempt to stabilize its concentration in samples of whole blood, but these concentrations of sodium fluoride are not readily available outside the analytical laboratory. This study was performed to assess the stability of cocaine in whole blood when stabilized in a commonly available concentration of sodium fluoride (0.25%), with or without concomitant refrigeration. Whole blood was enriched with cocaine to a final concentration of 900 ng/mL and added to flasks containing sodium fluoride (0, 0.25, 0.5, and 1.0%) or 0.25% sodium fluoride plus potassium oxalate (gray-top Vacutainer tubes), after which it was stored at 4 degrees C or at room temperature. Whole blood cocaine concentrations were measured at 0, 24, and 48 h by gas chromatography. Sodium fluoride at all concentrations, with or without refrigeration and potassium oxalate, effectively inhibited cocaine degradation, with 86-91% of the drug present after 48 h. In contrast, substantial degradation of cocaine occurred in the samples stored without sodium fluoride, regardless of temperature. Thus, the use of commercial gray-top Vacutainer tubes effectively stabilizes cocaine in blood during procurement, transport, and short-term storage.

Chromatography, Gas↗