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Biomedical subjects

H R Andersen

Publications and source records attributed to H R Andersen.

78 records · Page 5Linked to original sources
PubMed1980

Thin fluid-filled catheters for more accurate determination of pressures and their time derivatives.

A catheter-transducer system consisting of a thin fluid-filled teflon catheter and a transducer with a low displacement volume is presented. The thin catheter is especially suited for registration of pressure and the time derivatives in small caliber vessels. From theoretical considerations it is concluded that the best way of obtaining a correct damping ratio in the range of 0.6-0.7 in the system is to adjust the diameter of the catheter empirically to the characteristics of the transducer. Residual gas bubbles are a problem in most catheter-transducer systems, but due to the design of the catheter and to a special flushing method, reproducible results are rapidly and easily obtained. The damping ratio of the system is 0.6 and the band width is 35 Hz. In repeated experiments an identical influence of the temperature on the damping ratio could be demonstrated.

Blood Pressure Determination↗
PubMedDate not supplied

Effect of nickel chloride on hepatic lipid peroxidation and glutathione concentration in mice.

Intraperitoneal administration of nickel chloride enhanced hepatic lipid peroxidation (HLP) in 6-wk-old and 8-12-wk-old male CBA-mice but not in 3-wk-old mice. Nickel chloride administration depleted hepatic GSH in 8-12-wk-old mice but not in the younger age groups. After 300 mumol NiCl2/kg mortality occurred among 8-12-wk-old mice but not among the younger mice. Stimulation of GSH synthesis by administration of L-2-oxothiazolidine-4-carboxylate reduced nickel chloride induced mortality and HLP. Reduction of GSH synthesis by administration of buthionine sulfoximine (BSO) did not, however, enhance the toxicity of nickel chloride. This might be owing to chelation of the Ni(II)-ion by BSO. The results demonstrate age dependency and a protective effect of enhanced GSH synthesis in nickel chloride stimulated HLP.

Aging↗
PubMedDate not supplied

Thrombus organization plays no major role in late neointimal formation after angioplasty in porcine coronary arteries.

Thrombus organization has been suggested to play a major role in late neointimal formation after coronary angioplasty. We sought to describe the time sequence of lesion formation after angioplasty in porcine coronary arteries and to quantify the relation between early thrombosis and late neointimal formation. Deep vessel wall injury was induced by conventional balloon angioplasty in the circumflex (CX) and right coronary (RCA) arteries and by retraction of a chain-encircled balloon in the left anterior descendent artery (LAD). Lesions were assessed by histomorphometry at days 0, 1, 4, 7, 14, 28, and 56 after angioplasty. A response-to-injury index (lesion area/injury length) was determined for each artery. Angioplasty led to rupture/removal of media. Thrombus was present at the exposed adventitia at days 0, 1, and 4. From day 7, neointima was observed on the luminal side of the arterial wall. All thrombus had disappeared at day 28, at which only neointima was observed. Histomorphometry revealed that lesion formation after angioplasty was a gradually increasing process from day 0 to day 28 with no further growth from day 28 to day 56. Maximal thrombus size (day 4, RCA: 0.07+/-0.04 mm, CX: 0.23+/-0.16 mm, LAD: 0.15+/-0.11 mm) was significantly smaller than late neointimal formation (day 28, RCA: 0.68+/-0.18 mm, CX: 0.63+/-0.23 mm, LAD: 0.71+/-0.18 mm) in all three arteries (p < .03). Lesion formation after angioplasty is a gradually increasing process for 4 weeks. Maximal thrombus size is about four times smaller than late neointimal formation. Thus, thrombus organization plays no major role in late neointimal formation.

Angioplasty, Balloon, Coronary↗