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Biomedical subjects

D A Jensen

Publications and source records attributed to D A Jensen.

24 records · Page 2Linked to original sources
PubMed1992

Effects of angiographic needle size and subsequent catheter insertion on arterial walls. An in vitro experiment in human cadavers.

RATIONALE AND OBJECTIVES: It is widely believed that down-sizing catheters, and possibly needles, will decrease damage to the entry vessel in the performance of angiography. The purposes of this in vitro experiment are to determine if smaller needles produce less arterial wall damage than larger needles and to assess the influence of subsequent catheter insertion. METHODS: Each iliac artery pair from 35 fresh human cadavers was punctured three times with an 18-g needle and three times with a 21-g needle, for a total of 210 punctures. In two of each set of three, a 5- or 7-F dilator was passed. One hundred ninety-eight puncture tracts were usable and examined microscopically. They were graded on a scale of 1 to 3 in each of four categories: size of tract, margin irregularity, approximation of edges, and shape of tract. RESULTS: Chi-square analysis of the grading scores showed a significant shift of cases into lower damage grades when the smaller gauge needle was used for initial punctures (P < .0005). The subsequent insertion of a dilator, however, imposed further damage, such that the initial differences due to needle gauge were obliterated (P > .2). CONCLUSION: These data indicate that a 21-g needle produces less arterial wall damage than an 18-g needle, but that any safety conferred by the smaller needle is eliminated by the subsequent insertion of a 5- or 7-F catheter.

Adolescent↗
PubMed1991

Piperonyl butoxide as a tool in aquatic toxicological research with organophosphate insecticides.

Experiments were conducted to determine the effects of piperonyl butoxide, a synthetic methylenedioxyphenyl inhibitor of cytochrome(s) P450, on the toxicity of organophosphate insecticides to three cladoceran test species: Ceriodaphnia dubia. Daphnia magna, and Daphnia pulex. Coadministration of piperonyl butoxide effectively reduced the acute toxicity of four metabolically activated organophosphates (parathion, methyl parathion, diazinon, and malathion) and did not affect the toxicity of three organophosphates not requiring metabolic activation (dichlorvos, chlorfenvinphos, and mevinphos). These results indicate that piperonyl butoxide may be an effective tool in toxicological research focused upon identifying specific compounds responsible for toxicity in complex aqueous mixtures.

Animals↗
PubMed1991

Guide wire traversal test: retrospective study of results with fibrinolytic therapy.

The validity of the guide wire traversal test as a predictor of the outcome of selective fibrinolytic infusion therapy was investigated. A retrospective analysis of 51 consecutive urokinase infusions at the authors' institution revealed that the initial attempt at guide wire traversal of clotted vessels was successful in 36 patients and unsuccessful in 15. In those 15 patients in whom the initial guide wire traversal was unsuccessful, urokinase was infused proximal to the occlusion for 2-8 hours. In 10 of these 15 vessels, either guide wire traversal (n = 7) or complete lysis with only proximal infusion (n = 3) was then achieved. Final results for this group of 15 patients were similar to those found in the group of 36 patients in whom initial attempts at guide wire traversal were successful (chi 2 contingency analysis, P greater than .8). There were no statistically significant differences between these two groups with regard to ages of the grafts, duration of vessel occlusion prior to treatment, infusion times, or patient gender composition. These data indicate that failure to traverse a clotted vessel with a guide wire does not preclude successful urokinase fibrinolytic therapy in a substantial percentage of patients.

Aged↗
PubMed1989

The relationship of stride characteristics to pain before and after total knee arthroplasty.

The relationship between the changes in stride characteristics and the changes in pain that occurred before and after total knee arthroplasty (TKA) were examined in 18 patients with a diagnosis of osteoarthritis. The patients were observed after either bilateral or unilateral TKA. Measurements of stride characteristics by footswitch analysis and assessments of pain by visual analog scale were performed preoperatively and at five months and at 13 months postoperatively. Stride characteristics improved and pain diminished after surgery. Improvements, from preoperative to five months postoperative, were noted in seven of eight stride characteristics. The improvements in velocity and stride length were related to the decreases in pain over that period. Improvements from five months to 13 months postoperative were independent of the decrease in pain over that period and independent of the increase in active knee flexion angle. When evaluating stride characteristics after TKA, it is necessary to consider the effect of pain relief and to monitor the patient's ambulatory progress after pain diminishes.

Aged↗