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Biomedical subjects

J C Fuchs

Publications and source records attributed to J C Fuchs.

At least 19 recordsLinked to original sources
PubMed1982

The emerging role of epidural anesthesia in arteriography and in vascular operations.

Continuous epidural anesthesia offers special advantages for patients with vascular disease. In 193 patients who had this technique employed for aortofemoral arteriography, profound pain relief was provided and the accompanying vasodilation produced superior demonstration of collateral and small distal vessels. Eleven of these patients had epidural anesthesia for major vascular reconstruction operations. This caused minimal depression of pulmonary and myocardial performance during the procedure. Postoperative epidural analgesics improved the pulmonary performance by allowing normal pain-free breathing. No epidural complications were seen. Special precautions are described for the safe use of these techniques.

Analgesia↗
PubMed1980

Aspirin and dipyridamole decrease intimal hyperplasia in experimental vein grafts.

Release from platelets of a factor mitogenic for smooth muscle cells is a postulated mechanism for the pathogenesis of vascular intimal hyperplasia. In this study the effect of antiplatelet therapy was evaluated. Aspirin (165 mg twice daily) and dipyridamole (25 mg twice daily) were administered to six rhesus monkeys and six were given placebo only. Bilateral vein bypass grafts were placed in the iliac arteries. In addition, to evaluate the relative contribution of adventitial dissection and intimal injury, on one side the carotid artery and femoral vein were stripped of adventitia and on the other side the intima of these vessels were injured by the single passage of an inflated balloon tipped catheter. Animals were killed after 16 weeks. In grafts relative luminal area was determined by a photographic gravimetric method at three standard locations. Femoral veins and carotid arteries were classified as histologically normal or as exhibiting hyperplasia. All vessels with adventitial stripping were normal. All vessels with intimal injury in the placebo group except one exhibited intimal hyperplasia compared to the drug treated group in which over half were normal. Relative intimal area was significantly less in grafts from drug treated animals at all three locations and luminal area greater in two. These data suggest that vascular intimal hyperplasia can be reduced by treatment with antiplatelet agents.

Animals↗
PubMed1980

Surgical management of aortic abdominal aneurysms in patients with severe pulmonary insufficiency.

In view of the poor prognosis associated with the natural history of aortic abdominal aneurysms, this disorder is being surgically corrected in an increasing number of patients. There remains a group of patients with serious coexisting disease in whom careful consideration must be given concerning the risk of operation. One such group of patients is those with severe respiratory insufficiency. The records of ten patients with clinical and physiologic evidence of severe pulmonary insufficiency and concomitant aortic abdominal aneurysms were reviewed. While some patients were refused operation for severe cardiovascular disease, malignant disease and obesity, none was denied operation on the basis of severe respiratory insufficiency alone. With detailed respiratory assessment, appropriate preoperative preparation and careful attention to pulmonary function in the postoperative course, these patients can now undergo aortic abdominal aneurysm resection and grafting with a high expectation of success. In the ten patients, no operative deaths occurred, and all were discharged from the hospital having undergone a favorable postoperative course.

Aged↗
PubMed1979

Intimal thickening and hyperlipidemia in experimental primate vascular autografts.

Intimal thickening is a significant cause of late failure of aorto-coronary vein grafts. The microscopic appearance of this thickening has some similarities to the microscopic appearance of arterial atherosclerosis, and it has been suggested that hyperlipidemia may play a role in its pathogenesis. This study examines the morphology and lipid composition of autologous vein and artery grafts in normal and hyperlipidemic rhesus monkeys. Grafts were examined six months after insertion by light and electron microscopy and tissue lipids were determined quantitatively. Intimal thickening occurred in all grafts. Specific morphological and lipid compositional features of the grafts were influenced by the type of tissue used for grafting and the presence or absence of hyperlipidemia. However, the degree of intimal thickening per se could not be related to either of these two factors. It is concluded that surgical transplantation in this model provides the most powerful stimulus for intimal thickening and any additional effect on this process by hyperlipidemia is small.

Animals↗
PubMed1977

Digoxin kinetics during furosemide administration.

The urinary excretion of a 0.75-mg oral dose of digoxin was assessed in 8 healthy men during a control 5-day period and then, after a washout period of at least 2 wk, during a 5-day period when the subjects also took oral furosemide, 40 mg daily. Analysis of the raw data by a paired Student's test and analysis of variance of log-transformed urinary digoxin excretion data revealed no significant difference attributable to the addition of furosemide (F = 1.16; df = 1,21). The treatment by day interaction showed the slopes to be consistent between the two treatments. It seems that in the presence of normal renal function there is no need to alter loading or maintenance doses of digoxin when furosemide is also given. Analysis of variance with log transformation of data is suggested as a practical approach to handling digoxin urinary excretion results when the transformation linearizes the data through examination by the method of orthogonal polynomials.

Adult↗
PubMed1977

Effects of experimental hypertension and hypercholesterolemia on the lipid composition of the aorta.

This study evaluates alterations in canine aortic lipid composition under conditions of hypertension, hypercholesterolemia, or a combination of these factors. Hypertension was produced in the proximal thoracic aorta by creation of an aortic coarctation, whereas hypercholesterolemia was brought about by a lard-cholesterol diet in combination with thyroidectomy. Hypertension alone produced only minor changes in the lipid content of the arterial wall, but hypercholesterolemia yielded modest increases. The combination of hypertension and hypercholesterolemia, however, produced a striking increase in the total lipid content in the arterial wall. This change was most marked in the cholesteryl ester fraction, and a shift in cholesteryl ester fatty acids from linoleate to oleate was found. These data indicate that the interaction of hypertension and hypercholesterolemia produces alterations in lipid composition in a relationship which appears to be more geometric than arithmetic in nature.

Animals↗
PubMed1975

Static linear and nonlinear elastic properties of normal and arterialized venous tissue in dog and man.

Ten normal and four transplanted canine jugular vein segments and four human saphenous vein segments were studied to determine the in vitro static elastic properties of venous tissue and their modification by transplantation into the arterial system. Both the intraluminal pressure and the longitudinal force were varied, and the resulting dimensions were recorded photographically. Venous segments manifested a hysteresis response but showed minimum tendency to creep. The pressure-strain relationships were curvilinear with an initial, highly compliant phase over the physiological venous pressure range followed by a relatively noncompliant phase. This transition occurred at lower pressures for jugular segments than it did for saphenous segments. In contrast, comparable-sized canine carotide artery segments did not show this essentially noncompliant phase over the pressure range studied (0 to 200 cm H2O). At comparable pressures and strains, the jugular vein segments were stiffer than the saphenous vein segments in both the circumferential and the longitudinal directions. At comparable strains, the saphenous vein moduli were similar to those in the carotid artery segments. Jugular segments transplanted into arterial circuits became virtually noncompliant and markedly inhomogeneous, with wall thickening and a histologic picture of intimal proliferation. They showed no tendency to "arterialize," that is, they failed to assume either the elastic or the histologic characteristics of arterial tissue.

Biomechanical Phenomena↗