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Biomedical subjects

F W Smart

Publications and source records attributed to F W Smart.

71 records · Page 4Linked to original sources
PubMed1985

Proteoglycans from lungs of rabbits treated with pronase and cadmium chloride.

The composition of proteoglycans was studied in lungs from rabbits treated intratracheally with pronase, CdCl2, or saline. Proteoglycans were extracted from the lungs by 0.5 M and 4.0 M guanidine hydrochloride (GdnHCl) in sequence. Proteoglycans were isolated from the extracts by CsCl isopycnic centrifugation and fractionated by gel filtration on a Sepharose CL-4B column. The lungs from pronase-treated rabbits had approximately 33% greater total uronate than did lungs from saline-treated control animals, whereas CdCl2-treated rabbit lungs had 28% less uronate than did control lungs. Pronase-treated animal lungs had a greater proportion of hyaluronic acid and dermatan sulfate than did the control animal lungs. Relatively greater amounts of uronate were extracted by 0.5 M GdnHCl from the enzyme-treated rabbit lungs than from the CdCl2- or saline-treated animal lungs. The concentrations of hyaluronic acid and heparan sulfate in 0.5 M GdnHCl extract and dermatan sulfate in 4.0 M GdnHCl extract were greater in pronase-treated animal lungs than in control lungs. Gel filtration of proteoglycans sedimented at q greater than 1.45 revealed that pronase-treated animal lungs had proteoglycans smaller in molecular size than those in control lungs. The observations indicate that intratracheal treatment with pronase and CdCl2 alters the composition of proteoglycans in the lung, and such alterations are likely important in the pathogenesis of emphysema.

Animals↗
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Difficult cases in heart failure: beneficial effects of aldosterone blockade in heart failure.

The authors describe the use of spironolactone, an aldosterone receptor blocker, in a patient with heart failure refractory to conventional therapy. The clinical importance of this case is that not only does spironolactone improve symptoms, but its use also improves survival in patients with severe heart failure. Clinicians should be aware that this therapy has to be added to the medical armamentarium for patients with severe heart failure. In addition, it is important to point out that the use of the aldosterone receptor blockers and their beneficial effects in morbidity and mortality in heart failure has helped to understand more clearly the relationship between aldosterone and its importance in the pathophysiology of heart failure. (c)2000 by CHF, Inc.

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Impedance cardiography: a bridge between research and clinical practice in the treatment of heart failure.

This paper proposes that impedance cardiography could narrow the gap between heart failure clinical research and the appropriate and timely application of new knowledge and technology in the care of patients with heart failure. Research variables and measurement strategies, identified in the heart failure scientific literature between 1994-1999, are compared to measures that can be obtained through a cost effective, noninvasive technology--impedance cardiography. Emphasis is placed on case reports that illustrate how "real time" evaluation and trending of key hemodynamic variables through impedance cardiography monitoring has been used to apply state of the science knowledge and technology to improve the inpatient and outpatient management of care for patients with severe heart failure. (c)2000 by CHF, Inc.

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Difficult cases in heart failure: Bridge to beta blockade in severe heart failure: the use of phosphodiesterase inhibitors.

The authors describe the use of milrinone as a bridge to beta blockade in a patient with severe heart failure. This case is clinically important because in patients with severe heart failure phosphodiesterase inhibitors, unlike beta agonists, will retain their positive inotropic and vasodilator effects in the presence of beta blockade and, in addition, these agents will attenuate the negative inotropic side effects of beta blockers. Conversely, a beta blocker associated with a phosphodiesterase inhibitor will protect against myocyte loss and arrhythmias, may prevent sudden death, and will improve long-term symptoms and exercise tolerance. This combination is being investigated in a large, multicenter, double-blind, randomized trial of intravenous milrinone vs. placebo as a therapeutic tool to allow the initiation of carvedilol orally in patients hospitalized with class III/IV heart failure. (c)2000 by CHF, Inc.

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Difficult cases in heart failure: Ventricular resynchronization in refractory heart failure.

The use of a multisite transvenous pacemaker in a patient with refractory heart failure who experienced short-term symptomatic improvement is described. The improvement in heart failure symptoms was most likely related to resynchronization of atrioventricular and interventricular asynchrony. Large, multicenter, randomized trials of this technology are being performed to evaluate the importance of this therapeutic modality in the treatment of heart failure. (c)2000 by CHF, Inc.

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Cardiomyocyte transplantation in a porcine myocardial infarction model.

Transplantation of cardiomyocytes into the heart is a potential treatment for replacing damaged cardiac muscle. To investigate the feasibility and efficiency of this technique, either a cardiac-derived cell line (HL-1 cells), or normal fetal or neonatal pig cardiomyocytes were grafted into a porcine model of myocardial infarction. The myocardial infarction was created by the placement of an embolization coil in the distal portion of the left anterior descending artery in Yorkshire pigs (n = 9). Four to 5 wk after creation of an infarct, the three preparations of cardiomyocytes were grafted, at 1 x 10(6) cells/20 microL into normal and into the middle of the infarcted myocardium. The hearts were harvested and processed for histologic examinations 4 to 5 wk after the cell grafts. Histologic evaluation of the graft sites demonstrated that HL-1 cells and fetal pig cardiomyocytes formed stable grafts within the normal myocardium without any detrimental effect including arrhythmia. In addition, a marked increase in angiogenesis was observed both within the grafts and adjacent host myocardium. Electron microscopy studies demonstrated that fetal pig cardiomyocytes and the host myocardial cells were coupled with adherens-type junctions and gap junctions. Histologic examination of graft sites from infarct tissue failed to show the presence of grafted HL-1 cells, fetal, or neonatal pig cardiomyocytes. Cardiomyocyte transplantation may provide the potential means for cell-mediated gene therapy for introduction of therapeutic molecules into the heart.

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Difficult cases in heart failure: Atrioventricular interval optimization utilizing thoracic electrical bioimpedance.

The authors describe the use of thoracic electrical bioimpedance, a noninvasive, simple, low risk technique to optimize atrioventricular delay in a patient with a dual chamber pacemaker, right ventricular infarct, and symptoms NYHA functional class III-IV. Optimization of the atrioventricular interval was associated with improvement of hemodynamic parameters and resolution of the symptoms of heart failure. The application of noninvasive hemodynamic parameters might have a great deal of impact in the management of patients with several cardiovascular diseases. Multicenter studies are underway. (c)1999 by CHF, Inc.

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Difficult cases in heart failure: Left ventricular assist device implantation for the treatment of recurrent ventricular tachycardia in end stage heart failure.

The authors describe the surgical implantation of a left ventricular assist device (LVAD) in a patient with ischemic cardiomyopathy and recurring episodes of ventricular tachycardia with associated sudden death, as a therapeutic intervention for the recurrent ventricular arrhythmias. The clinical inference of this report demonstrates that these devices are useful as a bridge to heart transplantation, not only improving the symptoms of heart failure but also suppressing malignant ventricular arrhythmias. (c) 1999 by CHF, Inc.

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Difficult cases in heart failure: Bilateral renal artery fibrous dysplasia and heart failure.

The clinical characteristics as well as treatment of a patient with renal artery stenosis associated with uncontrolled hypertension and heart failure is described. Patients with similar findings should alert clinicians of this entity, since rapid diagnosis and treatment will assure a prompt relief not only of the increased blood pressure but also of the symptoms of heart failure. (c)1999 by CHF, Inc.

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Sudden death caused by bradycardia and asystole in a heart transplant patient with coronary arteriopathy.

The mechanism of death as a result of allograft ischemic heart disease is not well characterized. Ventricular tachycardia and fibrillation may not be the terminal events they often are in the general population. We report observations in a 41-year-old man with cardiac allograft arteriopathy who died suddenly while wearing an ambulatory monitor. The lethal rhythm was a progressive bradycardia terminating in asystole. Autopsy revealed epicardial and small vessel intramyocardial, coronary arteriopathy, and only mild allograft rejection. It is our belief that ischemia caused the bradycardic sudden death. We would like to hypothesize that prophylactic permanent pacemaker implantation may prevent bradycardic sudden death and improve survival in heart transplant patients with coronary disease.

Adult↗
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Elevated soluble interleukin-2 receptor levels early after heart transplantation and long-term survival and development of coronary arteriopathy.

Rejection dynamics after heart transplantation might be characterized by soluble interleukin-2 receptor levels. To determine whether elevated levels early (measured by enzyme-linked immunosorbent assay once weekly the first 3 weeks at time of heart biopsy) after transplantation predict mortality and development of coronary disease, the means of these three determinations and the endomyocardial biopsy scores (McAllister scale 0-10) were compared for survivors and nonsurvivors and patients who had coronary arteriopathy develop and those who did not. Fifty-five patients alive 30 days after heart transplantation were prospectively followed up. Overall, 47 patients were male (85%), and the median age was 51 years. Mean +/- SD follow-up was 26 +/- 15 months (range, 1 to 54 months). There were 38 survivors (69%), and coronary arteriopathy developed in 15 patients (27%). Whereas mean +/- SD heart biopsy scores for the early weeks were similar between survivors and nonsurvivors (3.6 +/- 1.4 vs 4.4 +/- 1.6; p greater than 0.05), the difference in soluble interleukin-2 receptor levels was significant (703 +/- 362 U/ml vs 1793 +/- 1070 U/ml; p less than 0.001). A mean level less than 1000 U/ml in any given patient predicted long-term survival with a 76% sensitivity, 79% specificity, and 88% negative predictive value. Mean receptor levels for those patients in whom coronary arteriopathy did not develop were 880 +/- 846 U/ml and for those with this difficulty, 1410 +/- 590 U/ml (p = 0.001). Late morbidity and mortality after heart transplantation seem predicted by early elevation of plasma soluble interleukin-2 receptor levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
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Presence of severe intimal thickening by intravascular ultrasonography predicts cardiac events in cardiac allograft vasculopathy.

BACKGROUND: The clinical utility of intimal hyperplasia detected by intravascular ultrasonography in predicting cardiac events in heart transplant recipients with cardiac allograft vasculopathy has not been previously investigated. METHODS: Intravascular ultrasonographic examination of 74 consecutive heart transplant recipients, including 62 men and 12 women with a mean age of 51 +/- 10 years (range 22 to 68 years), was performed at the time of annual angiography. Two groups of study patients were identified: group I consisted of patients with minimal, mild, or moderate intimal thickness by intravascular ultrasonography, whereas group II patients had severe intimal thickness. RESULTS: Patient characteristics were similar in both groups except for higher serum triglycerides (220 +/- 95 versus 165 +/- 79 mg/dl), more advanced donor age (28 +/- 11 versus 23 +/- 6 years) and greater duration of follow-up after transplantation (3.3 +/- 1.4 versus 1.8 +/- 1.2 years) in group II patients with severe intimal thickening (p < 0.01). Cardiac events were defined as the occurrence of sudden death, myocardial infarction, or the need for coronary revascularization via percutaneous or surgical intervention. One cardiac event occurred in group I patients (sudden death), whereas seven events were noted in the group II patients (p = 0.006). Cardiac events in the group of patients with severe intimal thickening included four patients with sudden cardiac death and three patients who underwent percutaneous revascularization procedures involving directional coronary atherectomy. Angiograms were normal in 62% of patients who had cardiac events. CONCLUSIONS: This study represents one of the first reports that provides evidence that severe intimal hyperplasia predicts the development of cardiac events even in the presence of a normal coronary angiogram.

Adult↗
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Vibrio vulnificus sepsis in solid organ transplantation: a medical nemesis.

We report two cases of Vibrio vulnificus wound infection leading to fulminant sepsis syndrome in immunocompromised solid organ transplant recipients. Features of clinical presentation in each of these cases suggest that host immune factors are of great importance in the virulence of this organism and that immunocompromised recipients of solid organ transplants are particularly vulnerable to life-threatening consequences from infection with Vibrio vulnificus. Prompt institution of antibiotic therapy and early consideration for surgical wound debridement are the mainstay of successful management. Heart and other organ transplant recipients should be educated and warned about the hazards associated with raw oysters and shellfish consumption and asked to exercise caution when exposed to a salt water environment.

Heart Transplantation↗
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Magnetic resonance imaging for assessment of tissue rejection after heterotopic heart transplantation.

Detection of myocardial rejection is difficult in patients with heterotopic heart transplantation because of the complex vascular anatomy present after transplant surgery. To determine whether magnetic resonance imaging might be useful for the assessment of heart rejection, eight patients with heterotopic heart transplantation were serially studied on 27 occasions. One patient had two donor hearts implanted, which allowed the study of 33 donor hearts. Data acquisition was gated to the ECG signal of the donor heart. Heavily T2-weighted (TE = 90 ms) velocity compensated spin-echo images were obtained through the midportion of the donor heart to assess tissue rejection. Donor heart function was qualitatively measured by acquiring multiphasic gradient echo images at the same level. A myocardial/skeletal muscle signal intensity ratio was calculated for the donor heart and compared to results of right ventricular biopsy obtained within 24 hours of imaging. A change in signal intensity ratio of 0.14 or more exceeded normal signal variation. All three episodes of rejection detected by biopsy were detected by magnetic resonance imaging. In three instances a significant change in the signal intensity ratio was associated with clinical evidence of rejection and a negative biopsy. Two instances were treated with a steroid bolus, and the signal returned to baseline. In three other instances a significant change in the magnetic resonance imaging signal occurred without clinical or biopsy evidence of rejection. Cardiac toxoplasmosis was present in one of these cases, and signal intensity returned to baseline after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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