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Biomedical subjects

F Fuentes

Publications and source records attributed to F Fuentes.

At least 37 records · Page 2Linked to original sources

Aortic root abscess. Initial experience using magnetic resonance imaging.

The detection of aortic root abscess by magnetic resonance imaging has not been described previously. We report a patient with an aortic root abscess that was successfully diagnosed by magnetic resonance imaging and echocardiography. Computed tomography failed to detect the abscess. The patient recovered with antibiotic therapy. Based on this case and other reports in the literature, we advocate treating similar patients without surgery. We recommend magnetic resonance imaging as an investigational method where the diagnosis of aortic root abscess is ambiguous.

Abscess

Positron imaging of myocardial infarction with rubidium-82.

Positron imaging provides tomographic images of regional myocardial perfusion but has required an on-site cyclotron. Rubidium-82 (82Rb) is a short-lived (T1/2 = 75 sec) positron emitter available from a generator. In order to determine the feasibility for its use to image acute myocardial infarction, 18 patients with transmural infarctions who had coronary arteriography were given 30-40 mCi of 82Rb intravenously and positron tomographic imaging was carried out within 96 hr after onset of symptoms. Nine simultaneous transaxial slices were obtained for each patient with a positron camera. Images were also reconstructed in a long-axis, short-axis, and three-dimensional display. One study could not be interpreted because of excessive lung activity. Fourteen normals were also studied. The infarct related artery determined by angiography was correctly diagnosed by positron imaging in all 17 patients as were all three prior infarcts by readers blinded to the clinical data. No defects were observed in normals or in noninfarcted myocardial regions. This study indicates that 82Rb should be useful for perfusion imaging in patients with acute myocardial infarction. The short half-life of 82Rb should make it ideal for providing serial assessment of perfusion in patients undergoing thrombolytic therapy.

Acute Disease

Role of coronary artery bypass surgery after intracoronary streptokinase infusion for myocardial infarction.

Intracoronary streptokinase infusion has been shown to improve left ventricular function and reduce hospital mortality in patients with acute myocardial infarction. Adjuvant coronary artery bypass surgery is of value in many of these patients who have recurrent angina, circulatory instability, severe coronary artery occlusive disease, or a high risk of reinfarction. There is little, if any, evidence that immediate coronary artery bypass surgery affects the results adversely--either because of recent myocardial infarction or recent streptokinase infusion, and early operation appears to be a safe and worthwhile modality of treatment in this group of patients with myocardial infarction.

Coronary Artery Bypass

Early bypass grafting following intracoronary thrombolysis with streptokinase.

Early bypass grafting following intracoronary thrombolysis with streptokinase may be indicated in patients with acute coronary artery thrombosis and severe coronary disease. To evaluate this approach, we prospectively studied 41 patients (32 men and nine women, mean age 53 years) with acute infarction. Emergency cardiac catheterization was performed within 18 hours after onset of chest pain and intracoronary streptokinase was given. All patients underwent bypass 3 to 10 days later (mean 7 days). Serial gated radionuclide left ventricular angiograms to determine ejection fraction were obtained on hospital admission, preoperatively, and 3 to 6 months later. Thirty-four patients had complete occlusion of the artery supplying the infarcted segment. In 30 patients (88%) reperfusion was not successful. In seven patients the artery was not totally thrombosed. Thirty-two patients (78%) had multivessel disease. An average of 2.8 grafts per patient were placed with an operative mortality of 2% (one patient). Serial measurements of ejection fraction were obtained in 23 patients in whom the admission ejection fraction was less than 50%. There was a significant increase in ejection fraction from admission (33% +/- 11%) to the preoperative measurement (41% +/- 9%, p less than 0.001), and this improvement persisted at follow-up (40% +/- 14%). Intracoronary streptokinase has been shown to restore blood flow to infarcting myocardium and to improve left ventricular performance. In patients with significant organic stenosis, the risk of bypass grafting 3 to 10 days after intracoronary streptokinase infusion appears to be no different from the risk of elective operation performed at a time remote from an acute infarction.

Adult

Sustained improvement in left ventricular function and mortality by intracoronary streptokinase administration during evolving myocardial infarction.

One hundred eighty-eight patients with acute myocardial infarction were studied prospectively from August 1980 to September 1982. One hundred thirty-six of these patients were entered into a intracoronary streptokinase study after informed consent was obtained. The remaining 52 patients, who either met exclusion criteria for the study or refused to participate, served as a control group and were treated as those in the study group except that they did not undergo emergency cardiac catheterization. Left ventricular function was determined in both groups by gated radionuclide ejection fraction (EF) on admission to the hospital, at discharge, and 6 months after discharge. With successful reperfusion up to 18 hr after onset of chest pain, mean left ventricular function in the study group improved (EF 39 +/- 13% on admission and 46 +/- 12% at discharge; p less than .001). Mean EF in control patients and those not achieving reperfusion did not change from admission to discharge. Mean EF at 6 month follow-up was not significantly different than at discharge in the study group or the control group. Total cardiac mortality in the control group was 19% compared with 10% in the study group (p = .06, NS). When patients admitted in pulmonary edema or shock (Killip class III or IV) were excluded from both groups, total cardiac mortality in the study group was significantly lower (4%) compared with in the control group (12.5%, p less than .05. The administration of intracoronary streptokinase during evolving myocardial infarction up to 18 hr after onset of chest pain may result in decreased mortality and sustained improvement in left ventricular function.

Aged

Beneficial effects of intracoronary thrombolysis up to eighteen hours after onset of pain in evolving myocardial infarction.

Coronary arteriography and intracoronary streptokinase (STK) infusion were performed on 89 patients with evolving acute myocardial infarction (AMI). Ventricular function was followed in these patients during their hospitalization by gated radionuclide ventriculography. In 35 of these patients thallium imaging was performed on admission and 4 hours after reperfusion. An additional 30 patients with AMI who either met exclusion criteria for the STK protocol or refused study served as a control group. In patients admitted 0 to 6, 6 to 12, or 12 to 18 hours after onset of pain, there was no difference in change in left ventricular ejection fraction (LVEF) from admission to discharge, in percent of patients with total occlusion demonstrating reperfusion, or in percent of patients demonstrating a significant increase in LVEF. The average increase in LVEF from admission to discharge in patients reperfused ws 8% (40% +/- 14% to 48% +/- 13%, p less than 0.001). No change in LVEF was demonstrated in the control population or in patients in whom coronary reperfusion was unsuccessful. Reperfusion produced an increase in thallium uptake in the infarct-related myocardium that was accompanied by an improvement in regional function. Failure of reperfusion produced no change in either thallium uptake or regional function.

Adult

Streptokinase reperfusion and early surgical revascularization in patients with acute myocardial infarction.

During a 21-month period, 150 patients with acute myocardial infarction were offered entry into a study comprising emergency cardiac catheterization, streptokinase infusion for thrombus if present, and coronary artery bypass surgery where appropriate. Forty refused or were excluded, and served as a control group. Approximately 80% of the remainder had coronary thrombosis and obtained benefit as a group from streptokinase reperfusion. Among the 44 who had coronary artery bypass mortality was low except in those having cardiogenic shock at the time of operation. Those without coronary thrombosis appeared to have a better result from early than from delayed operative revascularization. It appears that both streptokinase reperfusion and early coronary artery bypass have a beneficial role in the management of patients with acute myocardial infarction.

Cardiac Catheterization

Degradation of benzothiophene and related compounds by a soil Pseudomonas in an oil-aqueous environment.

Pseudomonas aeruginosa PRG-1, an isolate from oil-contaminated soil, degrades benzothiophene (BT) and other related compounds in a 5% oil-basal medium system. The organism cannot grow on BT alone; 0.05% yeast extract is a suitable substrate for its growth and for its attack on BT. Although BT is partially toxic to the bacteria, toxicity is reduced when BT is added in this oil system. The oil phase is emulsified by bacterial action during the process. Oxygen uptake studies with washed cell suspensions show increased respiration in the presence of BT. Endogenous respiration is markedly decreased by p-hydroxy-mercuribenzoate, whereas respiration due to BT is scarcely affected, suggesting that oxygen is added directly to BT. Results obtained both in direct degradation and in respiration studies indicate that 3-methyl-thiophene is more rapidly and extensively degraded than BT and other related compounds.

Biodegradation, Environmental

Cardiac evaluation of a physical rehabilitation program for patients with ischemic heart disease.

A reconditioning exercise program that was applied to group of 12 coronary patients resulted in an increase of their tolerance to physical work and of their maximal working capacity. In some instances the improvement in physical condition was accompanied by changes in indicators of cardiac function which suggest that an improvement in myocardial performance also occurred. Although some evidence of this has been presented, more studies are needed for substantiation. It is believed, on the other hand, that to explain the improvement of the patient, it is not necessary to invoke an improvement of myocardial performance. An improvement of patient's tolerance to physical work may also be explained by extracardiac mechanisms that produce changes in arterial peripheral resistance, regional blood flow distribution, overall mechanical efficiency, muscle capillarization, fiber size and mitochondrial enzymatic activity, patterns of sweating, adaptation between pulmonary ventilation and circulation, work of breathing efficiency, autonomic nervous system balance and in the adaptive responses of the neuroendocrine system which mediate between psychic and physiological behavior. All of these changes have been observed in healthy individuals submitted to physical training. It is plausible to assume that they may also occur in the patient with ischemic heart disease. What is to be shown is which one or which ones of these mechanisms prevail in a given individual.

Adult

Pharmacodynamic effects of ciprofloxacin, fleroxacin and lomefloxacin in vivo and in vitro.

The present study investigates the postantibiotic effect (PAE) in vivo, and the postantibiotic subinhibitory concentration effects (PA-SE) in vitro and SE in vivo of three 4-fluoroquinolones (ciprofloxacin, fleroxacin and lomefloxacin) against standard strains of Staphylococcus aureus and Escherichia coli. In vivo killing kinetics have also been performed using two different short administrations to study if the PAE duration could cover the time that the antibiotic was below the minimal inhibitory concentration (MIC) in serum. The results show that the three antimicrobial agents induced long PAEs (1.9-3.1 h) against the two microorganisms. Moderate but significant in vitro PA-SEs were also produced (1-->9 h). The in vivo SEs were not significant except when the effect of lomefloxacin on E. coli was assayed (0.54 h). Finally, the in vivo killing kinetics showed that the administrations that included the PAE duration were as effective as the schedule that maintained the antibiotic levels in serum above the MIC. Only when fleroxacin and S. aureus were assayed, this last administration was more effective (+0.9 log10 colony-forming units/thigh).

Animals