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Biomedical subjects

S C Smith

Publications and source records attributed to S C Smith.

315 records · Page 18Linked to original sources
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Susceptibility to spontaneous atherosclerosis in pigeons: an autosomal recessive trait.

The inheritance pattern for susceptibility to spontaneous (noninduced) aortic atherosclerosis in pigeons was determined by crossbreeding and backcrossing experiments with atherosclerosis-susceptible White Carneau and atherosclerosis-resistant Show Racer breeds. Susceptibility, assessed by the presence of grossly visible lesions at the celiac bifurcation of the aorta at 3 years of age, demonstrated an inheritance pattern consistent with an autosomal recessive Mendelian trait. Cell culture studies indicated that susceptibility is a constitutive property of aortic cells as evidenced by vacuole formation and lipid content in smooth muscle cells from various tissues in susceptible pigeons.

Animals↗
PubMedDate not supplied

Impromptu teaching and a collaborative approach. Enhancing the patient's comprehension and satisfaction.

Although multiple studies have shown that knowledgeable patients are better able to deal with health problems and are more compliant with prescribed medical regimens, health-care providers often fail to educate patients adequately. The most commonly professed barrier to patient education is time, even though nurses spend more time with patients than other members of the health-care team. This time is usually in frequent but small segments. These small segments of time can be used for impromptu teaching, an efficient means of conveying information when a patient's learning readiness and needs are high.

Consumer Behavior↗
PubMedDate not supplied

Physiology of the native heart and Thermo Cardiosystems left ventricular assist device complex at rest and during exercise: implications for chronic support.

Studies of patients supported with a left ventricular assist device have considered determinants of acute survival emphasizing the role of right heart function. In patients with refractory heart failure awaiting heart transplantation, chronic left ventricular assist device implantation may provide an opportunity for rehabilitation before surgery if hemodynamics are adequate at rest and during activities of daily life. For the assessment of the efficacy of the left ventricular assist device in this setting, four patients in whom the HeartMate pneumatic left ventricular assist device had been implanted were tested during graded supine bicycle exercise with Doppler echocardiography interrogation and central hemodynamic measurements. Patients with left ventricular assist device increased total left ventricular-left ventricular assist device complex output with exercise as Fick cardiac output increased from 5.7 +/- 1.5 to 8.6 +/- 3.1 L/min (mean +/- standard deviation). In two patients, peak left ventricular assist device rate and output were either present at the start of exercise or reached at mid-exercise and were associated with abrupt increases in left ventricular filling pressures (pulmonary capillary wedge pressure = 9 to 27 mm Hg and 12 to 24 mm Hg, respectively). During exercise, left ventricular end-diastolic size and pressure increased as right ventricular dimensions decreased or remained the same (patients 1, 3, and 4: 1.7 to 1.8 cm, 4.7 to 3.9 cm, and 2.6 to 1.8 cm, respectively) despite increased right atrial filling pressures, implying a decrease in functional right ventricular diastolic compliance. Although the left ventricular assist device functioned as a series pump at rest, Fick cardiac output exceeded left ventricular assist device output during exercise consistent with parallel ejection of the left ventricle through the native aortic valve. During exercise, residual left ventricular function may contribute to the hemodynamic response by (1) active filling of the left ventricular assist device to reduce filling time and to overcome left ventricular assist device inflow cannula impedance, (2) augmentation of total cardiac output with parallel ejection out of the native aortic valve, or (3) reduction of ventricular interaction-related changes in functional right ventricular diastolic compliance. When residual left ventricular function is sufficient, hemodynamics with exercise may be limited by peak left ventricular assist device rate. Although right ventricular function may affect acute postoperative survival, residual left ventricular function and peak left ventricular assist device rate may be important determinants of exercise performance during chronic implantation. A preliminary model of factors affecting the "left ventricular-left ventricular assist device complex" performance at rest and during exercise is presented.

Adult↗
PubMedDate not supplied

Detection of cytomegalovirus in paraffin-embedded postmortem coronary artery specimens of heart transplant recipients by the polymerase chain reaction: implications of cytomegalovirus association with graft atherosclerosis.

To assess the presence of cytomegalovirus in various tissues and its relevance to the development of graft atherosclerosis, 54 postmortem paraffin-embedded tissue samples from 15 heart transplant recipients who survived more than 100 days were analyzed by the polymerase chain reaction for cytomegalovirus. Eight patients had known previous cytomegalovirus exposure; 7 patients did not. Of the eight with known previous exposure, three patients (38%) died of graft atherosclerosis versus four (57%) of the seven patients without previous exposure. Of the 54 specimens, 49 were positive for beta-globin (inclusive positive control), including 38 coronary artery, five lung, five gastrointestinal, and one kidney. Only two coronary artery specimens were cytomegalovirus positive in a single patient with known cytomegalovirus exposure who did not have evidence of graft atherosclerosis at autopsy. Other tissues tested showed positive lung and stomach specimens in the patient with cytomegalovirus-positive coronary artery specimens and positive kidney, lung, and gastrointestinal specimens in a second patient. No specimens were cytomegalovirus positive in the remaining patients, despite the presence of graft atherosclerosis or previous cytomegalovirus exposure. Our data do not support the hypothesis that graft atherosclerosis is associated with latent cytomegalovirus infection of the coronary arteries. The role of cytomegalovirus in the pathogenesis of graft atherosclerosis is unknown, but possibly it represents a modulation of the immune system by remote infection.

Adolescent↗