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Biomedical subjects

C C Davis

Publications and source records attributed to C C Davis.

At least 55 records · Page 3Linked to original sources
PubMed1986

A five- to seven-year experience with externally-supported Dacron prostheses in axillofemoral and femoropopliteal bypass.

We have examined the clinical results of 56 externally-supported (EXS) Dacron grafts in the axillofemoral position and 117 in the femoropopliteal position. Results have been analyzed from two perspectives: primary patency concerns only those grafts that had never occluded; extended patency refers to all open grafts including those whose continued patency is the result of thrombectomy. The 5-to 7-year life-table patency rates are: axillofemoral 8 mm and 6 mm bypass: primary 75% and extended 97%; above-knee femoropopliteal 6 mm bypass: primary 78% and extended 93%; below-knee 6 mm femoropopliteal bypass: primary 41% and extended 91%. In contrast, the results for the 5 mm grafts used for femoropopliteal bypass were inferior to the 6 mm grafts: femoropopliteal 5 mm bypasses had an above-knee primary patency rate of 44% and an extended rate of 55%, with a below-knee primary patency rate of 15% and an extended rate of 32%. Rendering the noncrimped porous Dacron prosthesis kink and compression resistant by an external support coil appears to increase its potential for successful use, especially in 8 mm axillofemoral and 6 mm femoropopliteal bypasses.

Actuarial Analysis↗
PubMed1985

Microwave-field-driven acoustic modes in DNA.

The direct coupling of a microwave field to selected DNA molecules is demonstrated using standard dielectrometry. The absorption is resonant with a typical lifetime of 300 ps. Such a long lifetime is unexpected for DNA in aqueous solution at room temperature. Resonant absorption at fundamental and harmonic frequencies for both supercoiled circular and linear DNA agrees with an acoustic mode model. Our associated acoustic velocities for linear DNA are very close to the acoustic velocity of the longitudinal acoustic mode independently observed on DNA fibers using Brillouin spectroscopy. The difference in acoustic velocities for supercoiled circular and linear DNA is discussed in terms of solvent shielding of the nonbonded potentials in DNA.

DNA, Bacterial↗
PubMed1985

Thrombolytic therapy for delayed occlusion of knitted Dacron bypass grafts in the axillofemoral, femoropopliteal and femorotibial positions.

Selective intra-arterial streptokinase therapy successfully reopened ten axillofemoral and lower extremity Dacron bypass grafts that had undergone delayed closure from two to 47 months after implantation. In four, completion arteriograms revealed no runoff obstruction acquired since implantation; additional runoff obstruction had developed in the remaining six. All of the grafts without obstruction have remained open from two to 11 months. Three of the six grafts with obstruction have remained open from two and one-half to four months after specific surgical correction of the obstructive lesion. We conclude that intra-arterial streptokinase therapy is an effective means to reopen knitted Dacron grafts that have undergone delayed closure in the axillofemoral and above-knee femoropopliteal positions.

Aged↗
PubMed1983

An optical method for investigating the microwave absorption characteristics of DNA and other biomolecules in solution.

Direct determination of the microwave absorption characteristics of biological molecules in solution by an optical heterodyne technique is described. A visibly transparent sample is irradiated in a spatially nonuniform manner with pulsed microwaves, and the spatial variation in temperature increase measured by detecting the phase chirp impressed on a single-frequency He-Ne laser beam passing through the heated region. Results for several liquids and solutions such as water, methanol, various saline solutions, and solutions of DNA and DNA sodium salt in water are described. Where direct comparison is possible the results agree very well with published values. A significant increase in the absorption of DNA solutions compared with pure water has been observed that is consistent with microwave absorption by the longitudinal mode of the double helix.

DNA↗
PubMed1982

Severe left main coronary arterial stenosis with right coronary arterial occlusion: results of bypass graft surgery.

A detailed study was made of preoperative, operative and postoperative data from 69 patients with severe (70 percent or greater) luminal narrowing of the left main coronary artery and occlusion of the right coronary artery who underwent bypass surgery from December 1970 through December 1978. Preoperatively, 40.6 percent of patients were in functional class III and 55.1 percent in class IV. Ninety-six percent of those tested had a positive electrocardiographic treadmill test. Coronary bypass grafting was accomplished using standard techniques in all patients. An average of 2.7 grafts/patient were placed. The hospital mortality rate was 4.3 percent, and an additional 4.3 percent died before the end of 1 year. A history of congestive heart failure was a significant predictor (p less than 0.05) of postoperative mortality. An intraaortic balloon pump was not inserted in 64 patients, and our experience suggests that it was a necessary preoperative adjunct. A postoperative treadmill test was negative in 92 percent of those patients tested. Of those surviving 1 year postoperatively, 89 percent were in functional class I and 8 percent in class II. This study demonstrates a surgical mortality rate comparable with that of patients with left main coronary stenosis alone and a significantly better survival rate than that of similar patients treated medically.

Adult↗
PubMed1982

Results of combined left ventricular aneurysmectomy and coronary artery bypass: 1974 to 1980.

Left ventricular aneurysm repair with coronary artery bypass grafting was performed in 104 patients from 1974 through 1980. The patients' mean age was 57 years. Preoperatively, 48 percent were in New York Heart Association functional class III and 31 percent were in class IV. Stenosis of multiple vessels was common, as was a reduced ejection fraction (24 percent had an ejection fraction of less than 30 percent). Thrombus was present in 47 percent of resected aneurysms. Bypass grafting was performed to all graftable coronary vessels. Actuarial survival rates were 89.3 percent at 1 year, 86.1 percent at 2 years, and 74.5 percent (standard error 5.1 percent) at 5 years. One year postoperatively, 86 percent of the surviving patients were in class I, 11 percent class II, 1 percent class III, and 2 percent class IV. Patients who presented with angina alone had an excellent result, with 95 percent hospital survival. Congestive heart failure was an ominous finding, since four of five patients who developed it before discharge died in the hospital, and 38 percent of those who went into heart failure after discharge have died.

Adult↗