Biomedical subjects

E Frantz

Publications and source records attributed to E Frantz.

4 recordsLinked to original sources

PubMed1990

[Directional atherectomy--current status].

To deal with the problem of restenosis after PTCA, several new methods and devices for treating atheromatous lesions have been developed. Among the promising techniques, is the opportunity to remove atheromatous material with the directional coronary atherectomy catheter designed by J.B. Simpson. The atherectomy catheter consists of a housing at the catheter tip with a concave cutting device which is rotated at a speed of 2000 r.p.m. The housing is positioned at the stenosis by means of a central guidewire; the material to be removed protrudes into the housing. With an inflatable balloon on the opposite side, the position of the housing is fixed in the coronary artery, the plaque is pressed further into the orifice and severed by the rotating blade. The material removed remains in the tip of the housing and can be used for morphologic examination as well as for functional studies with individual cell cultures. Experience published to date encompasses the results of 1032 treated stenoses. The majority of the treated lesions, 53%, were localized in the left anterior descending coronary artery; in 22% the lesion were located in the right coronary artery, in 17% in an aorto-coronary venous bypass graft. Due to the difficulty in positioning the relatively rigid atherectomy catheter, the method has only been employed in the circumflex artery in 6%. In a substantial number of patients, the stenoses had already been subjected to PTCA; in 57% of 963 patients treated with atherectomy, angioplasty had been performed previously, in 25% bypass grafting had been carried out. The primary success rate was 93%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

Coronary artery fistula: an abnormality affecting all age groups.

A coronary artery fistula is an abnormal communication between a coronary artery and a cardiac chamber, great vessel, or other vascular structure. It is an infrequent but potentially important abnormality that can affect any age group. Most are congenital in origin, although other etiologies, in particular trauma, have been identified. Many are small and found incidentally during coronary arteriography, while others are identified as the cause of a continuous murmur, myocardial ischemia, congestive heart failure, or, rarely, bacterial endocarditis. The diagnosis should be considered in any patient presenting with a continuous murmur or in the setting of congestive heart failure, myocardial ischemia, or bacterial endocarditis without an obvious etiology. The pathophysiologic mechanisms resulting in symptoms include cardiac volume overload due to the shunting of blood and reduction of the myocardial blood supply due to "coronary steal." The diagnosis of coronary artery fistula may be suggested by the finding of a continuous murmur in a precordial location, which is atypical for patent ductus arteriosus. Two-dimensional echocardiography may demonstrate dilated coronary arteries, and pulse-wave and color-flow Doppler examinations can display turbulent flow in the suspected fistula and its receiving chamber or vessel. Angiography is generally needed to confirm the diagnosis and elucidate anatomic detail. The natural history of coronary artery fistula is variable, with long periods of stability in some patients and gradual progression of symptoms in others. Small fistulas detected incidentally at the time of angiography do not require immediate surgical correction, but careful follow-up is indicated because the potential for enlargement with physiologically important shunting exists and cannot readily be predicted. Spontaneous closure is uncommon. Surgical repair of the fistula is recommended for symptomatic patients and for some without symptoms because a quantitatively small shunt does not predict freedom from future symptoms or complications. Those selected for medical management must be followed closely.

Adolescent↗

PubMed1989

Bradykinin produces pulmonary vasodilation in fetal lambs: role of prostaglandin production.

Bradykinin produces pulmonary vasodilation and also stimulates production of other pulmonary vasodilators, including prostaglandin I2 (PGI2) and endothelial-derived relaxing factor. In 12 chronically instrumented fetal lambs, we therefore investigated potential mediation of the bradykinin response by PGI2 or other cyclooxygenase products. A 15-min infusion of bradykinin (approximately 1 microgram/kg estimated fetal wt/min) increased fetal pulmonary blood flow by 522% (P less than 0.05) and decreased pulmonary vascular resistance by 86% (P less than 0.05); plasma 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) concentration also increased (P less than 0.05). After cyclooxygenase inhibition by indomethacin (3 mg), bradykinin increased pulmonary blood flow by only 350% (P less than 0.05) and decreased pulmonary vascular resistance by 83% (P less than 0.05); plasma 6-keto-PGF1 alpha concentrations did not increase. The increase in pulmonary blood flow produced by bradykinin was greater before administration of indomethacin than after (P less than 0.05). These studies demonstrate that bradykinin produces fetal pulmonary vasodilation by at least two mechanisms, one dependent on and the other independent of PGI2 production, the latter mechanism predominating.

6-Ketoprostaglandin F1 alpha↗

PubMed1987

Histologically proven leukemia cutis carries a poor prognosis in acute nonlymphocytic leukemia.

A retrospective study of fifty-eight patients with acute nonlymphocytic leukemia was undertaken to determine the incidence of leukemia cutis and whether skin involvement serves as a prognostic indicator. A clinical diagnosis of leukemia cutis was made in eleven patients (19 percent), and five patients (8.6 percent) had biopsy-confirmed skin involvement. Patients with biopsy-proven leukemia cutis had a median postdiagnosis survival of only 12.5 weeks compared with fifty weeks for the group without skin involvement. We conclude that leukemia cutis is a biopsy diagnosis that occurs in a minimum of 8.6 percent of patients with acute nonlymphocytic leukemia in whom survival appears to be shortened.

Actuarial Analysis↗