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Biomedical subjects

T Little

Publications and source records attributed to T Little.

29 records · Page 2Linked to original sources

Usefulness of fish oil supplements in preventing clinical evidence of restenosis after percutaneous transluminal coronary angioplasty.

This study assesses the effect of dietary supplements with high dose omega-3 fatty acid (N3FA) on the frequency of clinical restenosis during the 6 months after successful percutaneous transluminal coronary angioplasty (PTCA). One hundred ninety-four patients (214 significant coronary narrowings) were randomized after successful PTCA to receive conventional medical therapy or to an identical regimen supplemented by high dose N3FA (4.5 g/day). Enrollment required angina pectoris and successful dilatation of all significant coronary narrowings. The subjects were randomly assigned to either no N3FA (control, n = 99) or N3FA supplementation (n = 95). After a 1-week trial period, 11 (group 2) declined further treatment because of side effects. The remaining 84 subjects (group 1) continued N3FA throughout the 6-month period. Monthly clinical follow-up was obtained in all patients. Ninety-two percent of patients had cardiac testing for evaluation of recurrent ischemia. Except for a greater percentage of women in the group refusing N3FA supplementation (group 2), the 3 groups were similar in demographic data, medical history, dietary habits, history of previous PTCA and angiographic characteristics. Of the 194 subjects, 56 had clinical restenosis (45 by cardiac catheterization, 8 by exercise testing and 3 by symptoms alone [refused further clinical testing]). Reocclusion rates were: group 1 19%, group 2 46%, and control 35%. Analysis both in accordance with the principle of intention to treat and for subjects who actually received N3FA revealed a significant effect of N3FA on preventing clinical restenosis (p less than 0.04 and p = 0.008, respectively). These data suggest that high dose N3FA supplements reduce the clinical restenosis rate after successful PTCA.

Angiography↗

Probe angioplasty of total coronary occlusion using an intracoronary Probing Catheter.

Coronary angioplasty (PTCA) of total coronary occlusion is limited by the inability of guidewires and conventional dilating catheters to cross all such lesions. We have therefore developed a technique for PTCA of chronic total coronary occlusions using the ultralow profile "balloon-on-a-wire" Probe. An intracoronary Probing Catheter is used to facilitate crossing the stenosis with a guidewire and then to deliver a Probe into the obstruction for balloon dilatation. This technique was used in 13 patients including six in whom other dilating systems had failed to cross the occlusion. Successful dilatation was performed in nine patients (67%). Among the six patients in whom other dilating systems had failed, dilatation was performed in five using the Probing Catheter technique with a successful outcome achieved in four (67%). The Probing Catheter technique offers a promising new method to apply "balloon-on-a-wire" technology to the dilatation of chronic total coronary occlusions. This method may allow successful dilatation when other dilating systems fail.

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Probe "balloon on a wire" ultra-low-profile coronary catheter: results of PTCA in 107 patients.

A new low-profile "balloon-on-a-wire" angioplasty catheter, the Probe (USCI), was used in 107 patients over a 4-month period. Twenty-nine patients had stable angina, 59 had unstable angina, and 19 had had myocardial infarction (MI) 3 to 15 days prior to the procedure; 71 patients had single-vessel and 36 had multi-vessel disease. In this series, 57 lesions were defined as complex. Successful dilatation was defined as a residual stenosis of less than 30%. Of 132 non-total obstructions, 127 (97%) were successfully dilated. Two distal lesions could not be reached, two lesions could not be crossed by the balloon, and a distal lesion dilatation resulted in acute closure in one case. Of 19 total obstructions, 16 (84%) were successfully dilated (mean residual stenosis 23%). The wire tip was unable to cross the lesion in the three unsuccessful procedures. Seven complications occurred in the series, all involving non-total obstructions: closure of a distal vessel and a side branch caused no clinical symptoms or EKG changes; three local dissections were tacked back with repeat dilatation; and two longitudinal dissections caused no apparent reduction in luminal diameter. The Probe's low-profile and exceptional trackability enabled it to cross very tight lesions with minimal trauma to the vessel wall. The high degree of conformability of the PET balloon minimizes vessel straightening or sheer forces and appears to reduce the potential for dissection. The device may therefore extend the indications and ease of PTCA while reducing complications of the procedure.

Angiography↗

External cardiac pacing in right ventricular infarction.

A patient with acute inferior wall myocardial infarction presented with clinical evidence of right ventricular infarction complicated by bradycardia and cardiogenic shock. Pharmacologic interventions produced no change in heart rate or blood pressure, and a transvenous pacemaker failed to capture the infarcting right ventricle. An external transthoracic pacemaker immediately increased the heart rate with a marked hemodynamic improvement. In the setting of right ventricular infarction, external pacing may be more effective than transvenous pacing, perhaps due to its ability to pace the left ventricle.

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Early noninvasive detection of successful reperfusion in patients with acute myocardial infarction.

Myoglobin (Mb) is a protein that enters rapidly and is rapidly cleared from plasma after coronary reperfusion. We sought to determine the accuracy with which a rapid rise in plasma [Mb] could predict successful coronary artery reopening in patients undergoing coronary arteriography in conjunction with attempted reperfusion in acute myocardial infarction. In 42 patients, plasma Mb levels were measured before and for at least 4 hours after attempted reperfusion. Thirty-five patients were successfully reperfused. In each, the plasma Mb level rose rapidly with peak [Mb] occurring at 111 +/- 8.1 (+/- SEM) minutes after application of therapy. In contrast, Mb levels rose more slowly in the seven patients who were not reperfused, with peak [Mb] occurring 360 +/- 61.4 minutes after attempted reperfusion. T25-100 (the time required for [Mb] to rise from 25% to 100% of peak value) was shorter in patients successfully reperfused (71 +/- 7.9 minutes) and longer (341 +/- 35.3 minutes) in patients in whom therapy was unsuccessful. A rapid rise in [Mb] after successful reperfusion was also evident by a more than 4.6-fold rise in [Mb] over the first 2 hours after reperfusion in all but five patients; in contrast, [Mb] rose by less than 4.6-fold over this same interval in every patient not successfully reperfused (sensitivity, 85%; specificity, 100%; predictive accuracy, 88%). We conclude that a rapid rise in plasma Mb level over the initial 2 hours after attempted reperfusion in acute myocardial infarction provides a useful index of successful reperfusion.

Adult↗

Patterns of myoglobin release after reperfusion of injured myocardium.

Myoglobin is an intracardiac protein that is released into the blood after myocardial injury and is then cleared rapidly by the kidneys. This study was undertaken to determine whether successful reperfusion of damaged myocardium could be assessed by examination of blood myoglobin concentration-time patterns. After release of a 2 hr occlusion of the mid left anterior descending coronary artery in 11 dogs that had been instrumented over the long term, immunoreactive arterial plasma concentration of myoglobin, [Mb], rose rapidly to a peak within 25 +/- 2(SEM) min (range 20 to 40). Individual peaks were three to 165 times the myoglobin levels immediately before release of the occlusion. Myoglobin was cleared rapidly from plasma, falling to one-half its peak level 38 +/- 3 min after the peak. Similarly well-defined peaks in [Mb] were evident in plasma from the great cardiac vein (GCV), with a mean time to peak of 16 +/- 2 min and a magnitude of two to 177 times prerelease values. In contrast, arterial and GCV creatine kinase activity-time curves showed less defined peaks and they occurred later and with more variability (60 to 330 min after reperfusion). In nine patients with acute infarction, successful coronary artery reopening was also accompanied by a sharp four- to sixteenfold rise in plasma [Mb] within 1 to 2 hr. Elevations in plasma creatine kinase were slower and more prolonged, peaking at 2 to 18 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Chronic lymphatic leukemia evolving into chronic myelocytic leukemia.

A diagnosis of chronic lymphatic leukemia (CLL) was made in an 83-year-old man on the basis of marked lymphocytosis (131.1 X 10(9)/L) and infiltration of the marrow (77%) by small lymphoid cells. The hemoglobin was 11.8 g/dL and the platelet count was 427.5 X 10(9)/L. With minimal and unsustained treatment, abrupt resolution of the lymphocytosis occurred with reciprocal emergence of a classic picture of chronic myelogenous leukemia (CML). During the hematologic evolution, blood lymphoid cells were isolated for surface marker, cytogenetic, and functional studies. E-rosette receptors, Fc-receptors, and membrane immunoglobulins were found on only 7.5%, 7.4%, and 10.0% of these cells. These cells also failed to express a CLL-associated antigen we have detected on approximately equal to 95% of the cells of all CLL patients studied, regardless of cell phenotype. In addition, the patient's lymphoid cells responded poorly to leucoagglutinin (LPHA) stimulation, showed increased spontaneous metabolic activity and exhibited the Philadelphia chromosome. These observations suggest that the patient's transient initial lymphocytosis was not due to CLL, but perhaps represented myeloid precursors in circulation prior to terminal differentiation.

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