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Biomedical subjects

D C Harrison

Publications and source records attributed to D C Harrison.

At least 415 records · Page 23Linked to original sources

Circulatory effects of diazepam in heart disease.

Diazepam was administered to ten patients with heart disease during diagnostic cardiac catheterization, in order to determine whether or not this drug's circulatory actions could alter results obtained during the procedure. Diazepam produced no change in baroreceptor sensitivity; however, there was a significant rise in heart rate and a significant fall in aortic systolic and left ventricular end-diastolic pressures. Cardiac index was unchanged, whereas stroke volume fell significantly. Systemic vascular resistance and peak left ventricular dp/dt did not change throughout the study. Clinical response in terms of sedation was judged to be satisfactory in eight patients, and no adverse effect on respiration was noted. Diazepam has little effect on basal circulatory and respiratory parameters when changes in these parameters are averaged for our ten patients. However, substantial changes in hemodynamic parameters did occur in several individuals, and such alteration in circulatory function must be considered when this agent is used routinely in patients having diagnostic cardiac catheterization.

Blood Pressure↗

Dynamic gadolinium-enhanced three-dimensional abdominal MR arteriography.

The abdominal aorta and renal, visceral, and iliac arteries were evaluated in 16 patients with three-dimensional Fourier transform imaging enhanced with gadopentetate dimeglumine. By imaging dynamically during the arterial phase of a 5-minute injection (0.2 mmol/kg), highly significant (P < .0001) preferential arterial enhancement (signal-to-noise ratio +/- standard deviation, 10 +/- 0.9), with minimal enhancement of the inferior vena cava (5.1 +/- 1.4) or background tissues (fat, 4.3 +/- 0.7; muscle, 2.4 +/- 0.5), was achieved in every patient. In six patients with angiographic and/or surgical correlation, 10 of 10 stenoses and two of two occlusions were correctly identified. No in-plane saturation or pulsatility artifact was identified in any of the 16 patients. In conclusion, dynamic imaging during the injection of gadopentetate dimeglumine is a promising technique for evaluation of the abdominal aorta and branch vessels.

Abdomen↗

Transvenous coronary angiography in dogs using synchrotron radiation.

The application of coronary angiography is limited because it requires arterial invasion and the direct injection of contrast agent into the coronary arteries. A prototype system has been developed which achieves sufficient sensitivity to the iodinated contrast agent to allow the visualization of coronary arteries in dogs after its intravenous injection. The system uses two fan beams of x-rays from an electron storage ring and a 300 element linear silicon detector. Two interlaced images, spaced at 150 eV above and below the K absorption edge of iodine (33.2 keV), are acquired and the logarithmic subtraction of these two images produces an image which has maximal sensitivity to iodine and minimal sensitivity to soft tissue and bone. This approach appears suitable for studies on human subjects.

Angiography↗