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Biomedical subjects

D Costello

Publications and source records attributed to D Costello.

At least 37 records · Page 2Linked to original sources
PubMed1984

Mitochondrial phosphate transport. Large scale isolation and characterization of the phosphate transport protein from beef heart mitochondria.

The phosphate transport protein from beef heart mitochondria has been purified on a large scale by hydroxylapatite chromatography in the presence of sodium dodecyl sulfate and urea. As shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (silver stain), the pure phosphate transport protein preparation consists of two protein bands (alpha and beta, ratio 1:1) with similar mobilities (34 kDa) which display identical peptide maps if fragmented with either CNBr or HCl/dimethyl sulfoxide/HBr. The complete amino acid composition of phosphate transport protein is presented. Quantitative determination of N-terminal amino acids underlines the purity of the preparation and shows for alpha and beta the identical amino-terminals H2N-Ala-Val-Glu-Glu-Glx-Tyr-. Qualitative digestion shows that carboxypeptidase A is able to release at least three amino acids from the C termini of the alpha as well as the beta band of phosphate transport protein. The nature of these two protein bands is discussed. The sum of phosphate transport protein (alpha + beta) per total mitochondrial protein amounts to 2.3% or 1.4 nmol of phosphate transport protein (34 kDa) per nmol of cytochrome b.

Amino Acids↗
PubMed1984

Extravascular lung water in patients with mitral stenosis: relationship to pulmonary capillary wedge pressure and Kerley B lines.

To evaluate the relationship between extravascular lung water, pulmonary capillary wedge pressure, and chest radiographic findings, extravascular lung water (EVLW) was assessed using double indicator-dilution techniques in 34 adult patients with mitral stenosis. Seven patients were studied 6 to 12 months after successful mitral valve replacement. In the 27 preoperative patients, septal lines were found to be indicative of elevated EVLW only in the presence of intravascular congestion. An excellent correlation between EVLW and pulmonary capillary wedge pressure was observed in these patients (r = .81, p less than .001), whereas only a rough correlation between scored radiographic findings and EVLW was observed. Postoperatively, septal lines were invariably associated with normal filling pressures and EVLW. Thus in both preoperative and postoperative mitral stenosis patients, interstitial Kerley B lines are insensitive markers of elevated extravascular lung water in the absence of pulmonary vascular engorgement. This emphasizes the importance of interpreting radiographic findings of extravascular fluid in conjunction with evaluation of the vascular bed in patients with chronic postcapillary hypertension.

Adult↗
PubMed1983

Radionuclide evaluation of the systolic blood pressure/end-systolic volume relationship: response to pharmacologic agents in patients with coronary artery disease.

To assess the response of the relationship between systolic blood pressure and end-systolic volume to pharmacologic agents with known cardiac effects, we studied 21 patients with known coronary heart disease by means of gated radionuclide angiograms during the infusion of phenylephrine. Each individual was studied during the infusion of phenylephrine twice, once as a control and the second time after the administration of either intravenous dobutamine, topical nitroglycerin ointment, or intravenous propranolol. Eight individuals received 10 micrograms/kg/min of dobutamine, which reduced resting cardiac volumes (p less than 0.01), raised ejection fraction (p less than 0.01), and shifted the slope (1.38 +/- 0.50 to 2.03 +/- 0.69, p less than 0.01) and pressure intercept received 2 inches of nitroglycerin ointment. Nitroglycerin increased ejection fraction (p less than 0.05) and reduced volumes (p less than 0.05) but did not alter either the slope (1.46 +/- 0.68 to 1.49 +/- 0.61, p = NS) or intercept (10.6 +/- 5.4 to 10.1 +/- 6.4 mm Hg, p = NS) of the relationship. Eight patients received 15 mg of intravenous propranolol. Propranolol reduced resting ejection fraction (p less than 0.05), increased volumes (p less than 0.05), and reduced both the slope (1.67 +/- 0.58 to 1.51 +/- 0.53, p less than 0.05) and the intercept (13.8 +/- 2.5 to 7.5 +/- 2.3 mm Hg, p less than 0.05) of the pressure-volume relationship. Thus the systolic blood pressure/end-systolic volume relationship can be assessed from radionuclide angiograms.

Blood Pressure↗
PubMed1983

Effects of airway pressure and lung volume on left ventricular transmural pressure-volume relationships in humans.

Positive airway pressure, combined with increased lung volume, decreases left ventricular compliance in dogs. To determine whether airway pressure or lung volume influences left ventricular diastolic properties in humans, we examined two consecutive cineangiograms with simultaneous esophageal and left ventricular pressure recordings in 14 patients. Both studies were performed during sustained inspiration, one with atmospheric airway pressure, and one with positive airway pressure (9.1 +/- 2.4 mm Hg). Positive pressure caused higher transpulmonary (airway minus esophageal) pressure and therefore greater lung volume in 10 of 14 patients, while four patients had lower transpulmonary pressures due to decreased inspiratory effort. When positive airway pressure and increased lung volume were present together (n = 10), left ventricular transmural (ventricular minus esophageal) pressure-volume curves revealed higher transmural pressures at comparable diastolic ventricular volumes. For example, at end-diastole mean left ventricular transmural pressure was 25.2 +/- 12.9 mm Hg (compared to 20.8 +/- 12.3 mm Hg during control studies, p less than 0.05), while ventricular volume was unchanged (189 +/- 87 compared to 185 +/- 81 ml, p = NS). When all 14 patients were considered together, this effect was linked more closely to higher transpulmonary pressure than to positive airway pressure. We conclude that human left ventricular transmural pressure-volume relationships are influenced by airway pressure and lung volume. Our findings further suggest that lung volume may be more important than airway pressure in this regard.

Coronary Disease↗
PubMed1983

Mechanism of increase in left ventricular end-diastolic pressure after contrast ventriculography in patients with coronary artery disease.

Elevation in left ventricular (LV) end-diastolic pressure (EDP) after contrast ventriculography (CV) has been proposed as a form of stress intervention in patients with coronary artery disease (CAD). The mechanism of this change has not been delineated. Accordingly, we performed two studies in CAD patients. In study 1 (n = 10), CV was repeated 3 minutes after an initial study. LVEDP rose from 14.9 +/- 6.6 mm Hg prior to the first ventriculogram to 26.9 +/- 10.8 mm Hg 3 minutes after the first ventriculogram (p less than 0.05) and immediately prior to the repeat CV (performed to evaluate the changes in volume produced by the first ventriculogram). In four patients with LV micromanometer pressures, the entire diastolic pressure-volume relation was shifted upward. LV ejection fraction (EF) and end-diastolic volume (EDV), peak LV pressure, and peripheral vascular resistance were unchanged at the time of repeat CV, and there was no correlation between the change in EDP and any of these variables. In study 2 (n = 6), gated radionuclide angiography was performed prior to and at minutes 2 to 7 after CV as were measurements of LV and right ventricular (RV) pressures. While both LV and RV EDP rose following contrast ventriculography, LV and RV EDV and EF were unchanged. We conclude that alterations in LVEDP after CV are unrelated to changes in LV or RV EDV and are most likely mediated by a decrease in myocardial compliance.

Adult↗
PubMed1983

Radionuclide analysis of pulmonary blood volume: the response to spontaneous angina pectoris and sublingual nitroglycerin in patients with coronary artery disease.

By manually assigning pulmonary regions of interest and deriving pulmonary time-activity (volume) curves, we were able to make count estimates of pulmonary blood volume (PBV) from gated cardiac blood pool scans. Five patients with coronary heart disease developed angina spontaneously while under a gamma camera. This produced an increase in cardiac volumes (p less than 0.05), a reduction in left ventricular ejection fraction (p less than 0.01), along with a marked increase in PBV (0.010 +/- 0.003 to 0.015 +/- 0.002 units, p less than 0.05). Nitroglycerin was then administered and reduced PBV in association with a return to normal in cardiac systolic function and size. In patients with stable chronic ischemic heart disease, sublingual nitroglycerin also reduced PBV (p less than 0.05), although not as much as when administered during an anginal episode. We conclude that gated imaging of the chest can be utilized to follow changes in PBV serially. These changes can be utilized to evaluate clinically important changes in hemodynamic status and the response to pharmacologic interventions.

Adult↗
PubMed1982

A method for measuring mean circumferential fiber shortening rate from gated blood pool scans.

Ejection fraction and ejection rate are easily obtained from gated cardiac images, but no method is available for calculating mean circumferential fiber shortening rate. We assumed that the cube root of left ventricular end-diastolic volume or counts is proportional to the minor axis of the left ventricle at end-diastole or end-systole. Mean circumferential fiber shortening rate is then equal to the [cube root of the end-diastolic volume (count) minus cube root of end-systolic volume (count)] divided by [cube root of end-diastolic volume (count) multiplied by the ejection time]. In 250 contrast ventriculograms, the standard mean circumferential fiber shortening rate (MCFSR) and that derived by the cube root method correlated well (r = 0.94). The mean value of MCFSR (0.85 +/- 0.35) was greater than the cube root value (0.75 +/- 0.35) (P less than 0.001). The regression equation was y = 0.86x + 0.02. Similar correlations were obtained from gated radionuclide images using a semiautomated program (r = 0.93) in 24 subjects or completely automated program (r = 0.85) in 28 patients. The regression equation between MCFSR and that derived from the cube root of counts for the semiautomated program was y = 0.82x + 0.04 and for the automated program was y = 0.84x + 0.004. Similar correlations, slopes, and intercepts were seen using circumferential fractional shortening for angiographic data when correlated with both the semiautomated and automated gated blood pool scan programs. These data indicate that MCFSR and circumferential fractional shortening may be obtained from gated blood pool images using cube root estimates of end-diastolic and end-systolic radii with a high degree of correlation with the standard contrast ventriculographic technique.

Adult↗
PubMed1982

Comparison of single-plane and biplane contrast analyses of right ventricular function and size.

To evaluate the utility of single and biplane right ventricular (RV) contrast angiograms, we evaluated 25 canine RV casts and 31 cineangiograms performed in patients during standard contrast ventriculograms. Both standard single and biplane formulae were utilized. In the 25 canine RVs, absolute volume was determined by water displacement. Both biplane (r = 0.96) and single-plane (r = 0.86) volumes correlated well with cast data. These formulae were then applied to contrast ventriculograms in the 31 patients (30-degree right anterior oblique and 60-degree left anterior oblique projections). The ejection fractions (EFs) calculated from the single-plane technique provided fair correlation with EFs derived from the biplane data (r = 0.81, y = 0.81X + 0.05). Similar correlations were noted when end-diastolic volume results were compared (r - 0.78, y - 0.57X + 56.4). However, while single-plane contrast right ventriculograms correlate with estimates of global RV function and size by biplane methods, considerable scatter of the data may limit its application in individual cases.

Aged↗
PubMed1981

Peak rate of left-ventricular ejection by a gated radionuclide technique: correlation with contrast angiography.

Gated radionuclide cardiac blood-pool imaging can produce reliable estimates of left-ventricular (LV) volume and ejection fraction. The ventricular volume curve can be used to develop normalized ejection rates, since count volumes and framing times are known. To test the accuracy of the peak ejection rate (maximum dv/dt), as derived by a standard computer algorithm, we studied 15 patients with coronary artery disease by both contrast ventriculography and radionuclide angiography. Max dv/dt by the radionuclide technique correlated well with the angiographic result: r = 0.92, p less than 0.01. The mean intraobserver variation was (plus or minus 12%) and the mean interobserver variation plus or minus 0.33 end-diastolic volumes per sec (plus or minus 13%). We conclude that maximum dv/dt may be derived from gated blood images, with reasonable accuracy and modest variability.

Adult↗
PubMed1978

Fracture of pacing electrode mimicking failure of pulse generator.

To our knowledge, this is the first reported case of spontaneous fracture of a pacing electrode with decreased amplitude of the pacing artifact, failure to capture, and intact sensing. We postulate that the difference in impedance of the pacemaker for sensing and stimulation may account for this phenomenon.

Aged↗