Biomedical subjects

E J Atkinson

Publications and source records attributed to E J Atkinson.

At least 73 records · Page 4Linked to original sources

PubMed1995

Inferior mesenteric venous sampling to detect colonic ischemia: a comparison with laser Doppler flowmetry and photoplethysmography.

PURPOSE: No single method has been identified that accurately and reliably detects patients with impending bowel infarction during aortic reconstruction. Serial sampling of blood gas from the inferior mesenteric vein (IMV) for detecting colonic ischemia was compared with two previously described techniques: laser Doppler flowmetry (LDF) and photoplethysmography. METHODS: Nine dogs underwent induced partial colonic ischemia followed by complete ischemia. Serial IMV blood gas measurements were obtained at four intervals: baseline, partial ischemia, complete ischemia, and reperfusion. Simultaneous direct colon wall LDF and PPG measurements also were obtained. RESULTS: Changes in pH, Po2, O2 saturation, and Pco2 demonstrated progressive acidosis, hypoxemia, and hypercapnia in association with progressive arterial occlusion and a reversal of these trends toward baseline after restoration of flow. The absence of a pulsatile photoplethysmography tracing and oxygen saturation less than 90% were predictive of altered perfusion but could not differentiate partial from complete ischemia. Although the differences in mean LDF values were statistically different during ischemia and reperfusion, there was considerable variability between each measurement. CONCLUSIONS: Analysis of blood gas from the IMV and pulse oximetry are useful techniques for detecting colonic ischemia, but only the former can distinguish partial from complete ischemia. The variability in colonic measurements with LDF limits its usefulness for detecting levels of colonic perfusion.

Animals↗

PubMed1995

Radiation necrosis or glioma recurrence: is computer-assisted stereotactic biopsy useful?

Fifty-one patients with supratentorial glioma treated with external beam radiotherapy (median dose 59.5 Gy) who then demonstrated clinical or radiographic evidence of disease progression underwent stereotactic biopsy to differentiate tumor recurrence from radiation necrosis. The original tumor histological type was diffuse or fibrillary astrocytoma in 21 patients (41%), oligodendroglioma in 13 (26%), and oligoastrocytoma in 17 (33%); 40 tumors (78%) were low-grade (Kernohan Grade 1 or 2). The median time to suspected disease progression was 28 months. Stereotactic biopsy showed tumor recurrence in 30 patients (59%), radiation necrosis in three (6%), and a mixture of both in 17 (33%); one patient (2%) had a parenchymal radiation-induced chondroblastic osteosarcoma. The tumor type at stereotactic biopsy was similar to the original tumor type and was astrocytoma in 24 patients (47%), oligodendroglioma in eight (16%), oligoastrocytoma in 16 (31%), unclassifiable in two (4%), and chondroblastic osteosarcoma in one patient (2%). At biopsy, however, only 19 tumors (37%) were low grade (Kernohan Grade 1 or 2). Subsequent surgery confirmed the stereotactic biopsy histological findings in eight patients. Follow-up examination showed 14 patients alive with a median survival of 1 year for the entire group. Median survival times after biopsy were 0.83 year for patients with tumor recurrence and 1.86 years for patients with both tumor recurrence and radionecrosis; these findings were significantly different (p = 0.008, log-rank test). No patient with radiation necrosis alone died. Other factors associated with reduced survival were a high proportion of residual tumor (p = 0.024), a low proportion of radionecrosis (p < 0.001), and a Kernohan Grade of 3 or 4 (p = 0.005). In conclusion, in patients with previously irradiated supratentorial gliomas in whom radionecrosis or tumor recurrence was clinically or radiographically suspected, results of stereotactic biopsy could be used to differentiate tumor recurrence, radiation necrosis, a mixture of both lesions, or radiation-induced neoplasm. In addition, biopsy results could predict survival rates.

Adult↗

PubMed1995

Determinants of reduced survival following hip fractures in men.

To assess determinants of poor survival after hip fractures in men, a population-based cohort study was conducted among 131 men in Rochester, MN, who had their first hip fracture during the period from 1978 to 1989, and an equal number of age-matched control men from the community. One hundred nine patients with fractures died during 373 person-years of followup, but only 75 control men died during 742 person-years of observation. The risk of dying increased with the level of comorbidity among hip fracture cases (hazard ratio 3.2; 95% confidence interval, 1.2-8.2), as well as with age (hazard ratio, 1.4 per 10-year increase; 95% confidence ratio, 1.1-1.8) and mental confusion during hospitalization (hazard ratio, 4.2; 95% confidence interval, 2.5-6.9). Discharge to a nursing home and low activity status also were predictors of death in the univariate analysis. Excess mortality among men with hip fractures can be explained best by interaction of the fracture with serious underlying medical conditions.

Activities of Daily Living↗

PubMed1994

Risk of hip fracture in women with vertebral fracture.

In a population-based retrospective cohort study, Rochester women aged 35-69 years who were first diagnosed with one or more vertebral fractures in 1950-1979 were followed for the development of a subsequent hip fracture. The 336 women with no history of hip fracture at the time of their vertebral fracture experienced 52 proximal femur fractures in 4788 person-years of follow-up. The standardized morbidity ratio (SMR) of observed to expected hip fractures was 1.8 (95% CI, 1.3-2.4) and was higher for intertrochanteric than cervical femoral fractures (SMR, 2.3 versus 1.3; P = 0.07). Hip fracture risk among women with symptomatic vertebral fractures was slightly less than in those with asymptomatic vertebral fractures (SMR, 1.8 versus 2.3; not significant), and younger women had no higher risk of a subsequent hip fracture than women who were > or = 60 years of age at the time of their vertebral fracture (SMR, 1.4 versus 1.8; not significant). Alternative explanations are possible, but these data are consistent with heterogeneity in the pathogenesis of different osteoporotic fractures.

Adult↗

PubMed1994

Fractures in an aging population of poliomyelitis survivors: a community-based study in Olmsted County, Minnesota.

OBJECTIVE: To determine the incidence of fractures in a cohort of survivors of paralytic poliomyelitis ("polio"). DESIGN: We conducted a population-based retrospective cohort study of residents of Olmsted County, Minnesota, who had an initial diagnosis of polio between 1935 and 1959 and survived the acute illness. MATERIALS AND METHODS: A comprehensive medical records-linkage system was used to retrieve all diagnoses of poliomyelitis in residents of the county for the specified 25-year period. For the 277 study subjects, the medical records were searched for the occurrence of fracture from the time of initial diagnosis of polio until death or the most recent clinical contact. All fractures were classified on the basis of type of associated injury and skeletal site of involvement. The influence of polio on the incidence of fractures was evaluated by estimating the cumulative incidence of new fractures after the diagnosis of polio and the standardized morbidity ratio. The relative influence of various factors on the risk of fracture was determined. RESULTS: Of the 277 Olmsted County residents with polio, 87 experienced 161 fractures, and the estimated cumulative incidence of any fracture after 40 years was 48%. The cumulative incidence of any limb fracture was 41% and was less than the expected value of 44% (P = 0.001). Only the risk of distal femoral and proximal humeral fractures was significantly higher than that among Olmsted County residents in general. The increased risk seemed to be associated with weakness and disuse of the involved limbs rather than with generalized osteoporosis. Theoretically, a greater capacity for bone remodeling in response to changes in muscle use might have protected patients with polio in childhood, but such persons were as likely to sustain a fracture as those with adult-onset poliomyelitis. CONCLUSION: These data indicate that survivors of paralytic poliomyelitis do not have an unusual risk of fracture except in affected limbs.

Adolescent↗

PubMed1994

Patterns and predictors of institutionalization in community-based dementia patients.

OBJECTIVE: To investigate patterns and predictors of institutionalization in a community-based sample of dementia patients. SETTING: The Mayo Clinic Alzheimer's Disease Patient Registry (ADPR), a community-based prospective registry. PATIENTS: Two hundred seventy-five participants, including 145 dementia patients and 130 controls on whom longitudinal follow-up data was available. The mean ages were 79.9 and 78.8 years, and the mean Mini-Mental State Examination (MMSE) scores at enrollment were 22.1 and 28.1 points for the demented cases and controls, respectively. MEASURES: Place of residence, marital status, number of direct support providers, global cognitive status, activities of daily living and instrumental activities of daily living were used in hazards modeling of institutionalization. RESULTS: The results from our community-based sample suggest a high rate of institutionalization for dementia patients. One-half of the sample of dementia patients were institutionalized within 2.5 years of enrollment in our patient registry. Identified assistance providers were absent in a significant proportion (36%) of our dementia sample. Marital status, global cognitive function, and functional status were significant terms in hazards models of institutionalization. Age, gender, number of direct caregivers, and dementia etiology were not associated with significant risk. Seventy-two percent of the dementia patients who died over the course of this study had been placed in nursing home care prior to death (with a mean length of stay of 2.8 years). CONCLUSIONS: Social (marital status) and disease-related variables (cognitive and functional status) are related to risk for institutionalization. These variables may be useful in estimating time to institutionalization in various clinical and research populations.

Aged↗

PubMed1994

Fracture risk in patients with Alzheimer's disease.

OBJECTIVE: To assess the risk of fracture following onset of Alzheimer's disease. DESIGN: Retrospective (historical) cohort study. SETTING: Population-based in Rochester, Minnesota. PARTICIPANTS: All 543 Rochester residents with onset of Alzheimer's disease during the 10-year period, 1975-84, and an equal number of age- and sex-matched controls from the community. MEASUREMENTS: Fractures were assessed through review of each subject's complete (inpatient and outpatient) medical records in the community. MAIN RESULTS: Rochester residents with Alzheimer's disease were no more likely to have a history of fracture prior to onset than were matched controls from the same population. During the year of onset, there was a 2-fold excess of fractures at various sites among those with Alzheimer's disease. The risk ratio for any fracture subsequently was 1.1 (95% CI 0.9, 1.3), and this slight increase was accounted for entirely by a 2.7-fold increase in the risk of hip fracture (95% CI 1.8, 4.2). CONCLUSIONS: Fracture risk was not increased before the onset of Alzheimer's disease, although there was an excess of fractures around the time that Alzheimer's disease came to clinical attention. Fracture risk was not elevated thereafter except for a substantial increase in the risk of hip fracture. This suggests a link with certain falls rather than generalized disuse osteoporosis.

Adult↗

PubMed1994

Fracture risk in patients with ankylosing spondylitis: a population based study.

OBJECTIVE: To assess the risk of fractures among patients with ankylosing spondylitis (AS). METHODS: A population based cohort study compared fracture incidence in an inception cohort of 158 Rochester, Minnesota residents newly diagnosed with AS between 1935 and 1989 with expected rates from the same community. RESULTS: In 2,398 person-years of observation, there was no increase in the risk of limb fractures, but there was a pronounced increase in the risk of thoracolumbar compression fractures (standardized morbidity ratio = 7.6; 95% CI, 4.3-12.6) among those with AS. CONCLUSION: These data point to the importance of measures aimed at maintaining axial skeletal status in patients with AS.

Adolescent↗

PubMed1993

Population-based study of survival after osteoporotic fractures.

Vertebral fractures are the most frequent of the fractures associated with osteoporosis, yet little is known of their impact on health in the United States. To aid in this understanding, the authors examined the survival rate of 335 residents of Rochester, Minnesota, who had an initial radiologic diagnosis of vertebral fracture between 1985 and 1989. Seventy-six died during 809 person-years of follow-up. The overall survival rate was worse than expected, and diverged steadily from expected values throughout the course of the study. At 5 years after diagnosis, the estimated survival was 61% compared with an expected value of 76% (relative survival = 0.81, 95% confidence interval (CI) 0.70-0.92). The 5-year relative survival after a hip fracture in Rochester was a comparable 0.82 (95% CI 0.77-0.87), but there was a much greater excess of deaths within the first 6 months as compared with patients with vertebral fractures. The 5-year relative survival rate after a distal forearm fracture was 1.00 (95% CI 0.95-1.05). Clinically diagnosed vertebral fractures are rarely fatal, and the reduced survival seen subsequently could related to comorbid conditions. Nonetheless, the excess mortality should be accounted for in assessing the public health impact of osteoporosis.

Arm Injuries↗

PubMed1993

Long-term fracture prediction by bone mineral assessed at different skeletal sites.

Bone mineral density (BMD) was measured at the lumbar spine and cervical and intertrochanteric regions of the proximal femur by dual-photon absorptiometry and bone mineral content was assessed at the distal and midradius by single-photon absorptiometry in an age-stratified random sample of 304 Rochester, Minnesota women aged 30-94 years. Over follow-up extending to 10 years (median 8.3 years), 93 women experienced 163 new fractures. After adjusting for age, these bone mineral measurements predicted the likelihood of any incident fracture due to moderate trauma, with relative hazards varying from 1.4 to 1.6 per SD decrease in baseline bone mineral. A 1 SD decrease in lumbar spine BMD increased the risk of a new vertebral fracture comparably to a 17 year increase in age; a 1 SD decrease in femoral BMD was comparable to a 13-14 year increase in age on the risk of a hip fracture. We conclude that bone mineral measurements made at a variety of skeletal sites can predict the occurrence for at least 8-10 years of moderate trauma fractures of the sort that might be related to osteoporosis.

Absorptiometry, Photon↗

PubMed1993

Levodopa therapy and survival in idiopathic Parkinson's disease: Olmsted County project.

We studied survival in all Olmsted County Parkinson's disease (PD) patients seen at the Mayo Clinic from 1964 to 1978, attempting to answer two questions: (1) What effect does levodopa have on survival in PD? and (2) Does the timing of levodopa administration influence survival? We chose this period because it allowed us to study patient records with a spectrum of disease durations before levodopa treatment; in many patients, the treatment delay was exclusively due to levodopa being unavailable prior to 1969. Mortality of the entire PD cohort (N = 179; 61% levodopa-treated) was greater than that of the general population (matched chronologically, geographically, and by age and gender). Lower age at onset of motor symptoms, lower Hoehn and Yahr stage at first neurologic visit for parkinsonism, and treatment with levodopa were all independent predictors of improved survival. Using a time-dependent Cox regression model, we assessed the impact of the timing of levodopa administration during the course of illness on mortality, while statistically controlling for other factors (ie, patient selection for levodopa treatment, and independent predictors of survival). Risk of death following initiation of levodopa was significantly reduced (p < 0.001), regardless of pre-levodopa duration of illness. This reduction gradually diminished over a period of 4 years on levodopa, but continued to be significantly reduced. After 4 years, increasing survival benefit again progressively accrued over time to at least 17 years of levodopa treatment (p < 0.001). At no point in time was levodopa treatment associated with increased mortality, arguing against substantial levodopa toxicity. However, despite levodopa-improved survival, mortality continues to be increased in PD relative to the general population.

Carbidopa↗

PubMed1993

Urban vs rural increase in hip fracture incidence. Age and sex of 901 cases 1980-89 in Olmsted County, U.S.A.

To determine if hip fracture incidence rates are greater in urban than in rural areas of the United States, as they appear to be in Scandinavia, we undertook a study in Olmsted County, Minnesota. During the decade 1980-89, the age- and sex-adjusted incidence of proximal femur fractures among urban residents of the central city of Rochester was 36 percent greater than among residents of the rural remainder of Olmsted County. The difference was almost entirely accounted for by an excess of fractures due to moderate trauma in elderly urban women. These first detailed results from the United States confirm earlier observations from Scandinavia that hip fracture rates are lower in rural areas.

Adolescent↗

PubMed1992

Ankylosing spondylitis in Rochester, Minnesota, 1935-1989. Is the epidemiology changing?

OBJECTIVE: To determine trends in the incidence and clinical presentation of ankylosing spondylitis first diagnosed between 1935 and 1989 among residents of Rochester, Minnesota, and in the survival of the patients. METHODS: Population-based descriptive study. RESULTS: The overall age- and sex-adjusted incidence rate was 7.3 per 100,000 person-years (95% confidence interval 6.1-8.4). The rate tended to decline between 1935 and 1989, but there was little change in the age at symptom onset or diagnosis over the 55-year study period. Overall survival was not decreased up to 28 years following diagnosis. CONCLUSION: These data indicate that there is a constancy in the epidemiologic characteristics of ankylosing spondylitis and suggest that previously study results indicating changes may have been due to biases in patient selection and study design.

Adolescent↗

PubMed1992

Incidence of clinically diagnosed vertebral fractures: a population-based study in Rochester, Minnesota, 1985-1989.

Vertebral fractures are the classic hallmark of osteoporosis, yet little is known of their epidemiology. The incidence of clinically diagnosed vertebral fractures was therefore directly assessed in the predominantly white (European descent) population of Rochester, Minnesota. Altogether, 341 Rochester residents were radiologically diagnosed for the first time with one or more vertebral fractures in the 5 year study period, 1985-1989. The overall age- and sex-adjusted incidence rate was 117 per 100,000 person-years (95% CI, 105 to 130). The age-adjusted rate in women (145 per 100,000 person-years) was almost twice that in men (73 per 100,000 person-years). Of all fractures, 47 (14%) followed severe trauma, 282 (83%) followed moderate or no trauma, and 12 (3%) were pathologic. Incidence rates for fractures following moderate trauma were higher in women than in men and rose steeply with age in both genders. In contrast, fractures following severe trauma were more frequent in men, and their incidence increased less with age. These Rochester rates are greater than those previously reported from studies in Britain and Sweden but lower than the incidence rates extrapolated from a prevalence study in this population.

Adult↗

PubMed1992

Is caffeine consumption a risk factor for osteoporosis?

High caffeine consumption has been proposed as a risk factor for osteoporotic fracture, but the evidence associating high caffeine intake with low bone density is inconsistent. We therefore examined the influence of caffeine consumption on bone mineral at six skeletal sites in an age-stratified random sample of white women residing in Rochester, Minnesota. After age adjustment, there was no association between overall caffeine consumption and bone mineral at five of the six sites. In the femoral shaft, however, there was a statistically significant interaction between age and caffeine consumption so that high caffeine intake was associated with slight reductions in bone mineral among elderly subjects but with modestly increased bone mineral at younger ages. When caffeine intake was categorized by source, no consistent influence of coffee, tea, or other caffeinated beverage consumption could be detected on bone mineral. Caffeine intake was, however, positively associated with cigarette smoking and alcohol consumption. After adjusting for age, caffeine consumption was not correlated with biochemical indices of bone turnover, circulating concentrations of estradiol and estrone, or other dietary and musculoskeletal variables. These data suggest that caffeine intake in the range consumed by a representative sample of white women is not an important risk factor for osteoporosis. Among elderly women, however, in whom calcium balance performance is impaired, high caffeine intake may predispose to cortical bone loss from the proximal femur.

Adult↗

PubMed1992

Risk of fractures in patients with pernicious anemia.

In a series of postmenopausal women previously studied by our group, pernicious anemia was associated with reduced bone mineral density of the spine and with vertebral fractures. To determine whether osteoporotic fractures represent an important clinical problem for such patients, we conducted a population-based retrospective cohort study of all Rochester, Minnesota residents newly diagnosed with pernicious anemia from 1950 through 1979. These 131 individuals were followed through the inpatient and outpatient records of all medical care providers in the community for 1550 person-years. In comparison with fracture rates from the general community, patients with pernicious anemia had a 1.9-fold increase in proximal femur fractures, a 1.8-fold increase in vertebral fractures, and a 2.9-fold increase in distal forearm fractures (all p less than 0.05). Increases in the risk of proximal humerus and pelvis fractures were not statistically significant. Clinicians should be aware that pernicious anemia is associated with an increased risk of osteoporotic fractures, but the mechanism is unknown.

Adult↗

PubMed1992

Secular trends in the incidence of postmenopausal vertebral fractures.

Several studies suggest secular increases in hip fracture incidence through this century, but little is known about such trends for vertebral fracture. We have examined changes in the incidence of clinically ascertained vertebral fractures among Rochester, Minnesota residents aged 35-69 years, that were first diagnosed between 1950 and 1989. Our results indicate no overall increase in incidence over the 40-year period. Categorization of fractures according to the level of preceding trauma, however, revealed a significant increase in the incidence of fractures following moderate trauma among women aged 60-69 years. This increase occurred between 1950 and 1964, and leveled off thereafter. Rates for severe trauma fractures among postmenopausal women, and for vertebral fractures from any cause among younger men and women, remained stable. The rise in moderate trauma fractures in postmenopausal women paralleled that for hip fractures in Rochester and began to plateau at around the same time. It might have resulted from increased diagnosis of vertebral fractures, but the increase in hip fracture incidence is inconsistent with this explanation. An increase in the prevalence of osteoporosis, however, might account for the trend in both types of fractures.

Adult↗

PubMed1992

Transurethral microwave thermotherapy for prostatism: early Mayo Foundation experience.

As part of a multicenter investigative trial, transurethral microwave thermotherapy of the prostate was used in 60 men with symptomatic benign prostatic hypertrophy. A single office treatment on the Prostatron, a device that provides concurrent microwave heating of the prostate and conductive cooling of the urethra, was well tolerated and caused no major adverse events. Symptomatic improvement, especially the decrease in nocturia and urgency, was dramatic, and urinary flow was improved at 6 weeks. Continued follow-up suggests that further improvement will be achieved and that transurethral microwave thermotherapy has a role in the treatment of benign prostatic hypertrophy.

Academic Medical Centers↗