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Biomedical subjects

R Sampath

Publications and source records attributed to R Sampath.

23 records · Page 2Linked to original sources
PubMed1991

Management of malignant ventricular arrhythmias using antitachycardia devices.

Cardioverter defibrillators were implanted in 26 patients at Charleston Area Medical Center for management of cardiac arrest (7 patients), and drug refractory sustained ventricular tachycardia (19 patients). A variety of operative approaches and concomitant surgical procedures were utilized in the implantation of these devices. No operative deaths occurred. A superficial wound infection was the only operative complication. During the follow-up period (9.3 +/- 5 months), 11 of 26 patients (46 percent) had a defibrillator discharge and one death occurred (3 percent), which was due to heart failure. Patients with malignant ventricular arrhythmias may present with sustained monomorphic ventricular tachycardia with associated syncope, pre-syncope or without any associated symptoms. Unfortunately, cardiac arrest may be the initial presentation. The use of antitachycardia devices such as implantable cardioverter defibrillators and antitachycardia pacemakers has allowed physicians to more successfully treat patients with malignant ventricular arrhythmias. In a significant number of patients with these arrhythmias, such devices are now used as first-line therapy.

Adult↗
PubMed1982

Management of ascending aortic aneurysm complicating coarctation of the aorta.

Four patients with coarctation of the aorta complicated by an aneurysm of the ascending aorta are described. One patient, treated only medically, died suddenly. For the 3 patients who underwent operation, management was similar. Pharmacological control of blood pressure and repair of the aortic coarctation to achieve anatomical reduction in afterload (stage I) were followed after an interval of one to five weeks by surgical repair of the ascending aortic aneurysm (stage II). Initial repair of the coarctation relieves proximal hypertension, thereby decreasing the chance of progressive dissection or rupture of the aneurysm. It also permits safe arterial cannulation for perfusion during correction of the aneurysm in the second stage. In patients not requiring valve replacement in stage II, continued long-term follow-up for progression of aortic valvular disease appears to be necessary.

Adolescent↗
PubMedDate not supplied

Shear stress-mediated changes in the expression of leukocyte adhesion receptors on human umbilical vein endothelial cells in vitro.

Extensive monocyte recruitment is an early phenomenon associated with the development of atherosclerotic lesions, suggesting an active role for the involvement of adhesion receptors expressed by endothelial cells. In this study we describe the contribution of hemodynamic shear forces in regulating the expression of a few of the monocyte adhesion receptors, including intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), and E-selectin on endothelial cells. A parallel plate flow chamber and recirculating flow loop device was used to expose human umbilical vein endothelial cells (HUVECs) to different levels of shear (2-25 dyn/cm2). Subsequently the cells were analyzed either for shear induced changes in the mRNA levels of adhesion receptors by Northern blot analyses or for changes in the surface expression of ICAM-1 using flow cytometry. Results from the fluorescence analysis showed a transient increase in the surface expression of ICAM-1, 12 hr after exposure to 25 dyn/cm2 shear, returning to basal levels within 24 hr. This was quite different from the time dependent response of ICAM-1 to lipopolysaccharide (LPS), where ICAM-1 expression was maximally induced 18-24 hr post-stimulus. ICAM-1 mRNA level appeared slightly elevated after exposure to shear for 1 hr, compared to basal values, but dropped below basal levels within 6 hr. This biphasic response was seen irrespective of the magnitude of applied shear stress. VCAM-1 mRNA expression, in contrast, decreased below the baseline expression within an hour after onset of flow, and appeared to be considerably down-regulated within 6 hr. After exposure to shear for 24 hr, no increase in mRNA levels could be detected for either molecule, at any shear magnitude. E-selectin mRNA was less responsive to shear stress, especially at the lower magnitudes of shear. After an hour of exposure to flow E-selectin mRNA level appeared slightly reduced compared with control levels, but it remained at this level even after 6 hr of flow. These results indicate that the expression of adhesion receptors is sensitive to local shear stresses in a manner that is molecule specific in the short term even though prolonged exposure to flow results in similar down-regulation for both ICAM-1 and VCAM-1.

Cell Adhesion Molecules↗