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Biomedical subjects

P N Olson

Publications and source records attributed to P N Olson.

At least 19 recordsLinked to original sources
PubMed1997

The prevalence of diffuse idiopathic skeletal hyperostosis (DISH) in two large American Midwest metropolitan hospital populations.

OBJECTIVE: There are no published large-scale studies of the overall prevalence of diffuse idiopathic skeletal hyperostosis (DISH) and it has been proposed that the prevalence is greater than previously reported. We thus decided to review chest radiographs in a population of patients over 50 years of age seen at two large but differing metropolitan hospitals in a major American Mid-west city. DESIGN AND PATIENTS: The posterior-anterior and lateral chest radiographs of 1363 patients were reviewed for evidence of DISH at the University of Minnesota Hospital and Clinic. There were 500 consecutive inpatient admissions, 540 consecutive patients who attended the outpatient clinics and 326 patients collected from our film archive. A population of 1001 patients seen at Hennepin County Medical Center was also studied. It was possible to subclassify this latter group with respect to race. RESULTS AND CONCLUSION: Using strict criteria, i.e., four or more levels involved, the overall prevalence of DISH in the male population over age 50 years was 25% and in the female population over age 50 years was 15%. This prevalence climbed to 28% in males over 80 years and to over 35% in males over age 70 years. In females over 80 years, the prevalence was found to be 26%. Although our population base was small, DISH was found to be less common in the black, Native-American and Asian populations. The prevalence of DISH was also found to be far lower in a similar white population with osteoporosis. The overall prevalence of DISH was higher than expected in a predominantly white population over age 50 years with a lesser incidence in the black, Native-American and Asian populations, suggesting a genetic origin of the condition.

Aged↗
PubMed1997

Use of MRI in evaluating postoperative changes in patients with bone and soft tissue tumors.

We reviewed the clinical, surgical and magnetic resonance imaging (MRI) findings in 80 patients who underwent resection of primary benign or malignant bone or soft tissue tumors. There were 18 benign and 62 malignant tumors. Although 31 patients were originally thought to have recurrence, on review only 20 patients were considered to have recurred. Of these, three were found only to have postoperative changes at surgery. Seventeen patients actually had recurrence of tumor. We believe that the presence of an actual mass lesion on MRI is the cornerstone for the correct diagnosis of recurrent tumor.

Adolescent↗
PubMed1996

"Incisura" of the ascending aorta and vascular pedicle width in the cardiac transplant patient.

BACKGROUND: The purpose of this study was to evaluate three findings in cardiac transplant patients: the appearance, etiology, and incidence of "incisura" (a characteristic indentation) of the ascending aorta; the vascular pedicle width, which usually appears enlarged on standard chest radiographs; and clearing of the retrosternal clear space. MATERIAL: Two hundred sixty-one cardiac transplantations were performed at the University of Minnesota before December 31, 1992. The appearance, etiology, and incidence of an incisura were studied; the vascular pedicle width was measured; and the rate of clearing of the retrosternal clear space was determined. RESULTS: Forty-six percent of the patients whose ascending aorta could be visualized on the lateral chest radiogram showed an incisura. Approximately one third of the patients showed continued opacification of the retrosternal space postoperatively. The width of the vascular pedicle in this series of cardiac transplant patients measured 60.9 +/- 22.8 mm (standard deviation, 11.4 mm), in comparison to a normal of 48 +/- 5.0 mm. CONCLUSIONS: An incisura of the ascending aorta and the widened vascular pedicle are normal postoperative chest radiographic findings in cardiac transplant patients and should not be misconstrued as abnormalities.

Anastomosis, Surgical↗
PubMed1996

Effect of prepuberal and postpuberal gonadectomy on heat production measured by indirect calorimetry in male and female domestic cats.

OBJECTIVE: To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats. DESIGN: Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age. ANIMALS: 18 male and 18 female clinically normal domestic shorthair cats. PROCEDURE: Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg). RESULTS: Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01). CONCLUSIONS: These data suggest that resting metabolic rate in cats decreases after gonadectomy. CLINICAL RELEVANCE: A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.

Analysis of Variance↗
PubMed1995

Hyperextension strain or "whiplash" injuries to the cervical spine.

PURPOSE: To define "whiplash" radiologically. MATERIAL AND METHODS: A full cervical spine radiographic series (including flexion and extension views) was reviewed in 40 patients with clinically proven "whiplash" injuries and compared to the radiographs in 105 normal controls. The level and degree of kinking or kyphosis, subluxation, and the difference in the amount of fanning between spinous processes on flexion and extension films were measured in each patient. RESULTS: Localized kinking greater than 10 degrees and over 12 mm of fanning, often occurring at the level below the kinking or kyphosis, occurred mainly in the group of whiplash patients (sensitivity 81%, specificity 76%, accuracy 80%). CONCLUSIONS: Localized kinking greater than 10 degrees and fanning greater than 12 mm are useful measurements by which to separate patients with true whiplash injuries from those with minor ligamentous tears. Flexion and extension views are essential to help define whiplash and other ligamentous injuries of the cervical spine.

Adult↗
PubMed1995

Cyclops lesion.

Postoperative impingement of the knee following ACL reconstruction does occur. MRI can be useful in the diagnosis of the patient who is not recovering as quickly as expected following surgical reconstruction. MRI allows the assessment of 1) tunnel position and alignment, 2) graft integrity, 3) the menisci for possible re-tear or extension of previous tears, and 4) joint for scar tissue and cartilaginous bodies either loose or fixed.

Adult↗
PubMed1994

Diagnosis of breast implant rupture: imaging findings and relative efficacies of imaging techniques.

OBJECTIVE: The purpose of this study was to compare the efficacies of mammography, sonography, CT, and MR imaging in the detection of breast implant rupture and to analyze the imaging findings. SUBJECTS AND METHODS: Thirty-two women with 63 silicone breast implants participated in the study. All but one had signs and symptoms suggestive of rupture, and all had requested that their implants be removed before they were enrolled in this imaging study. All patients had film-screen mammography, sonography, CT, and MR imaging. Twenty-two ruptures were found at surgery; 21 were intracapsular and one was extracapsular. The relative efficacies of the imaging studies were determined, and the imaging findings were compared with the surgical results. RESULTS: Of the 32 women with 63 implants, mammographic sensitivity for detecting implant rupture was only 23% but the specificity was 98%. Sonography had a higher sensitivity (59%), but its specificity was significantly lower (79%). CT had a sensitivity of 82% and a specificity of 88%. MR was the only imaging technique that consistently provided evidence that enabled the evaluation of intracapsular and extracapsular ruptures. The sensitivity and specificity of MR imaging were 95% and 93%, respectively. CONCLUSION: Our results show that MR imaging is more sensitive and specific for the detection of breast implant rupture than is mammography, CT, or sonography.

Adult↗
PubMed1994

Staging of musculoskeletal tumors.

Staging of musculoskeletal neoplasms is important for planning chemotherapy and surgical procedures. Accurate staging has increased in importance with advancements in limb salvage procedures. This article outlines concepts, techniques, and potential problems with staging of neoplasms. It is important to remember that biopsy should be preformed after consultation with an orthopedic surgeon specialized in tumor surgery.

Adolescent↗
PubMed1993

Pet (dog and cat) overpopulation in the United States.

Over half of all United States (US) households own a dog or cat. The veterinary profession can now provide health care for dogs and cats of affluent or devoted owners that rivals the health care offered many human patients. Unfortunately, as many pets receive medical and surgical care that becomes increasingly sophisticated, other pets in the US receive no veterinary care at all. Additionally, millions of pets are humanely killed in US animal shelters because owners are not committed to the continual responsibilities of pet care. Although the total dog and cat population is unknown in the US, as is the total number of pets killed, estimates suggest that between one-tenth and one-quarter of the entire US pet population is destroyed annually because of a surplus dog and cat problem. Pet overpopulation is attributable to relinquishment and abandonment, as well as to birth rates; thus, veterinarians must strive to reduce pet overpopulation by not only curbing reproduction, but also by decreasing the major cause of pet death in the US (i.e. humane killing). Thus, the veterinary profession must take a prominent role in the campaign to prevent the deaths of healthy animals for whom homes cannot be found, just as it has done to prevent the deaths of sick animals that do have homes.

Animal Rights↗