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Biomedical subjects

S A Olson

Publications and source records attributed to S A Olson.

At least 37 records · Page 2Linked to original sources
PubMed1995

Anatomy of the medial distal femur: a study of the adductor hiatus.

The proximity of the vascular structures traversing the adductor hiatus in the medial distal femur is a potential concern for the surgeon. The distance from the adductor tubercle to the adductor hiatus was measured in both lower extremities in 24 skeletally mature cadavers. This distance ranged from 8.0 to 13.5 cm (mean 10.0). The area up to 8 cm proximal to the adductor tubercle, anterior to the medial intermuscular septum, appears to be a safe interval for avoiding vascular structures with percutaneous or limited open surgeries of the medial aspect of the distal femur.

Cadaver↗
PubMed1995

Biomechanical consequences of fracture and repair of the posterior wall of the acetabulum.

We measured the distribution of contact area and pressure between the acetabulum and the femoral head of cadaveric pelves in three different conditions: intact, with an operatively created fracture of the posterior wall, and after anatomical reduction and fixation of the fracture with a buttress plate and interfragmentary screws. The study involved eight cadaveric hip joints from five pelves loaded to 2000 newtons in simulated single-limb stance. Measurements were made with pressure-sensitive film. The acetabulum was divided into three areas--the anterior wall, the superior aspect, and the posterior wall--for the analysis of the data. Creation of a fracture of the posterior wall was followed by an increase in contact area, maximum pressure, and contact force in the superior aspect of the acetabulum. A concomitant decrease in these parameters was observed in the anterior and posterior walls. Anatomical reduction and fixation of the fracture with a plate and screws did not restore the pattern of loading to pre-injury levels.

Acetabulum↗
PubMed1995

The effect of prostaglandin E1 on liver adenine nucleotides and cytoplasmic enzymes in a porcine model of normothermic hepatic ischemia.

The liver has been judged relatively resistant to ischemia, but prolonged inflow occlusion at normothermic conditions can produce evidence of reversible or irreversible hepatocellular damage. Cytoprotective agents have been used both experimentally and clinically to afford extended viability of hepatocytes under reduced perfusion. One agent, prostaglandin E1, has been described clinically as effective in sustaining liver function under ischemic conditions. We have sought to verify this observation in an experimental model using prolonged normothermic inflow occlusion. Twenty miniature pigs were anesthetized and subjected to subtotal normothermic hepatic inflow occlusion (portal vein, hepatic artery, choledochal vessels) to allow for sufficient splanchnic decompression. Half of the animals received pretreatment with prostaglandin E1 (alprostadil) 500 micrograms intravenously. Inflow occlusion was maintained for 2 hours followed by reperfusion and killing 24 hours later. As a measure of functional preservation, the tissue adenine nucleotides adenosine monophosphate, diphosphate, and triphosphate (AMP, ADP, ATP) were measured in ischemic liver by freeze-clamping and high-performance liquid chromatography during occlusion and after reperfusion. Cytosolic enzyme determinations (aspartate transaminase, alanine transaminase, lactate dehydrogenase) were also made before occlusion and after reperfusion. As a possible indicator of cellular injury, blood ionized Ca++ was measured before inflow occlusion and after reperfusion. Although no difference was found in levels of AMP and ADP between prostaglandin E1 and control animals, ATP levels rose significantly higher during recovery in prostaglandin E1 animals at 60 minutes and 24 hours after reperfusion (13.97 +/- 1.29 and 13.60 +/- 0.91 mumoles/gm dry weight prostaglandin E1 vs. 9.25 +/- 0.97 and 9.80 +/- 0.85 mumoles/gm dry weight co control, P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1993

The computerized tomography subchondral arc: a new method of assessing acetabular articular continuity after fracture (a preliminary report).

The criteria to treat acetabular fractures operatively versus nonoperatively continue to evolve. The technique of roof arc measurements was developed to identify the extent of superior acetabulum left intact after fracture. Computerized tomography (CT) of the superior 10 mm of the acetabular articular surface evaluates the area equivalent to roof arc measurements of 45 degrees. CT provides increased detail of the superior acetabulum involved with the fracture. Our current criteria for selecting cases for nonoperative treatment are as follows: 1. The acetabular articular surface is intact in the superior 10 mm of the joint on CT evaluation. (Fractures that enter the acetabular fossa, but not the articular surface in the superior 10 mm are included in this group.) 2. The femoral head remains congruent with the superior acetabulum out of traction on the anteroposterior and 45 degree oblique radiographic views of the pelvis. 3. When a posterior wall fracture is part of the injury pattern, a minimum of 50% of the posterior wall articular surface is intact at the most involved level as determined by CT.

Acetabulum↗
PubMed1991

A review of computerized tomography evaluation of acetabular fractures--part 1.

Computerized tomography is an established modality for use in the evaluation of acetabular fractures. As open reduction and internal fixation of acetabular fractures becomes more common, the need for an accurate understanding of the fracture anatomy is critical. An anatomic study of the innominate bone is reported and the relevant standard radiographic landmarks as seen with computerized tomography are illustrated.

Acetabulum↗
PubMed1991

Magnetic resonance imaging evaluation of the spinal canal following arthrodesis and removal of sublaminar wires.

Seven patients who underwent posterior spinal fusion with Harrington instrumentation and sublaminar wires, and subsequently had these implants removed, were evaluated for evidence of spinal canal compromise with magnetic resonance imaging (MRI) at the sites of the sublaminar wires. All fusions were solid. The sites of 33 wires (27 levels) were evaluated with MRI. The average time the wires were in the spinal canal was 24.6 months. The average time following wire removal at the time of MRI was 61.7 months. Twenty-eight of 33 (85%) wire sites had no evidence of spinal canal compromise. Five sites had minimal (less than 15%) spinal canal compromise. The permanent structural changes in the spinal canal attributable to sublaminar wires appears to be quite modest.

Adolescent↗
PubMed1990

Disseminated intravascular coagulation complicating Ender's nailing of a pathologic fracture in prostatic carcinoma. A case report.

Disseminated intravascular coagulation (DIC) occurred after closed Ender's pinning of a pathologic fracture of the humerus in a 58-year-old man with metastatic prostatic carcinoma. A review of the oncologic and urologic literature revealed that coagulopathy can be associated with prostatic carcinoma. This association seems not to have been previously reported in the orthopedic literature.

Bone Nails↗
PubMed1987

Degradation and biosynthesis of the glucose transporter protein in chicken embryo fibroblasts transformed by the src oncogene.

The rate of glucose transport in cultured fibroblasts is regulated to a number of physiological variables, including malignant transformation by src, glucose starvation, and stimulation with mitogens. Much of this transport regulation can be accounted for by variations in the amount of transporter protein in the cells. To determine the mechanisms by which levels of the transporter are regulated, we measured the rates of synthesis and degradation of the transporter by pulse-chase experiments and immunoprecipitation of the transporter. We found that transformation by the src oncogene results in a large decrease in the rate at which the transporter protein is degraded but that it does not appreciably increase the rate of transporter biosynthesis. On the other hand, glucose starvation and mitogen stimulation increase the rate of transporter biosynthesis, although a role for control of degradation is possible in these circumstances also. Variations in the rate of glucose transport or the amount of the transporter are not associated with phosphorylation of the transporter protein.

Animals↗
PubMed1987

Removal of sublaminar wires after spinal fusion.

Eighteen patients who had had spinal fusion using Harrington rods with sublaminar wires underwent removal of the implants because of tenderness over the implants. There were no important complications. At final follow-up, no patient had a change in neurological function as compared with the preoperative assessment, and all reported relief of the preoperative tenderness. We concluded that the removal of rods and sublaminar wires from patients who have had a spinal fusion is clinically safe and effective.

Adolescent↗
PubMed1984

Antagonism by gram-negative bacteria to growth of Yersinia enterocolitica in mixed cultures.

The inhibition of the growth of Yersinia enterocolitica by other gram-negative bacteria in mixed cultures at 32 degrees C was not the consequence of a depletion in essential nutrients, an unfavorable change in pH or oxygen tension or the production of toxic metabolic products. The inability of Y. enterocolitica to attain its potential maximum population in mixed cultures appeared instead to result from "metabolic crowding," which occurred when the faster-growing antagonistic organism reached stationary-phase density. Lowering the incubation temperature, a technique commonly used in "cold" enrichment for isolation of Y. enterocolitica, tended to equalize growth rates and thereby allowed Y. enterocolitica to achieve a higher population.

Antibiosis↗