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Electron beam tomography (EBT) is a noninvasive method used to detect coronary artery calcium (CAC). Due to the age-associated increase in incidence and magnitude of CAC, interpretation of results can be difficult. The purpose of this study was to develop a set of age- and gender-stratified CAC distributions to serve as standards for the clinical interpretation of EBT scans. Between 1993 and 1999, 35,246 asymptomatic subjects, 30 to 90 years of age, were self-referred for CAC screening using an Imatron EBT scanner. CAC score was calculated based on the number, areas, and peak computed tomographic density for each detected calcific lesion. CAC score in each coronary artery was equal to the sum of all lesions for that artery and the total CAC score was equal to the sum of the score of each artery. Total CAC scores were assigned to a percentile according to age and gender. CAC scores were reported at the 10th, 25th, 50th, 75th, and 90th percentiles for 16 age and/or gender groups. The prevalence of CAC increased with age for men and women. The extent of CAC differed significantly between men and women in the same age group. In summary, this study reports the distribution of CAC score by age and gender. Knowledge of the distribution of CAC, the effect of age on the total CAC score as well as the differences in total CAC scores that exist between men and women of similar age will assist the clinician in interpreting EBT CAC results.

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BACKGROUND: Fulfillment of patients' expectations may influence health care utilization, affect patient satisfaction, and be used to indicate quality of care. Several different instruments have been used to measure expectations, yet little is known about how different assessment methods affect outcomes. OBJECTIVE: The object of the study was to determine whether different measurement instruments elicit different numbers and types of expectations and different levels of patient satisfaction. DESIGN: Patients waiting to see their physician were randomly assigned to receive 1 of 2 commonly used instruments assessing expectations or were assigned to a third (control) group that was not asked about expectations. After the visit, patients in all 3 groups were asked about their satisfaction and services they received. SUBJECTS: The study subjects were 290 male, primary care outpatients in a VA general medicine clinic. MEASURES: A "short" instrument asked about 3 general expectations for tests, referrals, and new medications, while a "long" instrument nested similar questions within a more detailed list. Wording also differed between the 2 instruments. The short instrument asked patients what they wanted; the long instrument asked patients what they thought was necessary for the physician to do. Satisfaction was measured with a visit-specific questionnaire and a more general assessment of physician interpersonal skills. RESULTS: Patients receiving the long instrument were more likely to express expectations for tests (83% vs. 28%, P <0.001), referrals (40% vs. 18%, P <0.001), and new medications (45% vs. 28%, P <0.001). The groups differed in the number of unmet expectations: 40% of the long instrument group reported at least 1 unmet expectation compared with 19% of the short instrument group (P <0.001). Satisfaction was similar among the 3 groups. CONCLUSIONS: These different instruments elicit different numbers of expectations but do not affect patient satisfaction.

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Gender is an independent prognostic factor for survival from lung cancer with the relative risk of lung cancer death for men compared to women being 1.3. This observation remains unexplained but in vitro data suggests a stimulatory effect of androgens on lung cancer growth. We hypothesized that androgen deprivation improves survival in men with lung cancer compared to hormonally intact men with lung cancer. On the basis of age, race and region, we matched 44 men with lung cancer and bilateral orchiectomy with 88 men who had lung cancer and no history of orchiectomy and compared their survival. Since hazards were non-proportional we chose the generalized gamma model to describe the survival function. The survival was significantly different between the two groups (p = 0.0048) with the orchiectomy group having a better two year overall survival. This retrospective study suggests that androgen depletion may significantly improve the short term survival of men with lung cancer but further, prospective investigation is required for confirmation.

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Many studies have suggested that hormone replacement therapy reduces the risk of coronary heart disease. Electron beam tomography is a highly sensitive noninvasive method by which to detect coronary artery disease. Our objective was to investigate whether hormone replacement therapy had an effect on coronary artery disease as determined by electron beam tomography in postmenopausal women. Nine hundred fourteen self-referred postmenopausal women older than 50 years underwent electron beam tomography. Each woman completed a questionnaire regarding age, risk factors, menopausal status, and hormone replacement therapy. Women taking hormone replacement therapy were slightly younger (57.8 years) than those not (60.7 years). A significantly higher incidence of a family history of myocardial infarction and smoking history was found in the group taking hormone replacement therapy, whereas more diabetics were in the group not taking hormone replacement therapy. The mean total coronary artery scores for women receiving hormone replacement therapy and not receiving hormone replacement therapy were 54.2 and 86.2, respectively (p = 0.02). Independent predictive variables of a positive coronary artery calcium score with multiple logistic regression analysis were age, hypercholesterolemia, diabetes, and estrogen use. These results suggest that hormone replacement therapy is associated with less coronary artery disease in postmenopausal women as determined by electron beam tomography.

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BACKGROUND AND PURPOSE: The ex vivo effect of aspirin (ASA) on platelet aggregation, the platelet component of thrombosis, was studied at repeated intervals in a cohort of patients taking aspirin for recurrent ischemic stroke prevention to define the maintenance of efficacy over time. METHODS: We administered increasing doses of aspirin (from 325 to 1300 mg/d) to patients with previous ischemic stroke and determined the extent of inhibition of platelet aggregation after 2 weeks and thereafter at approximately 6-month intervals. RESULTS: Over 33 months, 306 patients had platelet aggregation studies performed to define their initial response to ASA therapy. Of these, 228 had complete and 78 had partial inhibition of platelet aggregation at initial testing. To date, 119 of those who had complete inhibition and 52 who had partial inhibition have undergone repeat testing at least once. At repeat testing 39 of the 119 (32.7%) with complete inhibition at initial testing had lost part of the antiplatelet effect of ASA and converted from complete to partial inhibition without change in ASA dosage. Of the 52 with partial inhibition at initial testing, 35 achieved complete inhibition either by ASA dosage escalation (in 325 mg/d increments) or fluctuation of response at the same dosage, but 8 of those 35 (22.8%) had reverted to partial inhibition when tested again. Overall, 8.2% of patients ultimately exhibited ASA resistance to 1300 mg/d-8 of 52 (15.4%) with partial inhibition and 6 of 119 (5.0%) with complete inhibition at initial testing. CONCLUSIONS: The antiplatelet (and presumably the antithrombotic) effect of a fixed dose of ASA is not constant over time in all individuals. The mechanisms by which increased dosage requirement or ASA resistance develops and the clinical significance of this development are currently undefined.

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BACKGROUND AND PURPOSE: Although warfarin and perhaps aspirin may be effective in preventing thromboembolism in patients with nonvalvular atrial fibrillation, some patients develop cerebral infarction despite these therapies. The purpose of this study was to determine inhibition of platelet aggregation in patients on aspirin and platelet reactivity in those on warfarin in the Stroke Prevention in Atrial Fibrillation study. METHODS: Twenty-four patients in the Stroke Prevention in Atrial Fibrillation study at the University of Illinois at Chicago, 17 on enteric-coated aspirin 325 mg/d and 7 on warfarin to produce an International Normalized Ratio of 2.0 to 4.5, had platelet aggregation studies performed during a 10-month period and interpreted by an investigator blinded to therapy. Epinephrine, adenosine diphosphate, collagen, and arachidonic acid were used as aggregating agents. Compliance was determined by pill count for those patients on aspirin. RESULTS: Seven patients taking aspirin had partial and 10 had complete inhibition of platelet aggregation. Three of seven patients on warfarin had hyperaggregable platelets. Compliance was 80% or greater for those patients taking aspirin. One patient on warfarin had partial inhibition of platelet aggregation. CONCLUSIONS: Some patients in the Stroke Prevention in Atrial Fibrillation trial on aspirin 325 mg/d did not achieve complete inhibition of platelet aggregation. Others had hyperaggregable platelets. These findings suggest platelet-dependent mechanisms for aspirin and warfarin failure to prevent stroke in these patients.

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Ornithine decarboxylase (ODC) is extremely unstable in mammalian cells. This unusual characteristic facilitates rapid fluctuations in the activity of this enzyme in response to variations in its biosynthesis. Unfortunately, very little is known about the mechanism or regulation of this ODC-specific proteolytic pathway. This study describes the production and characterization of a variant of the rat hepatoma HTC cell line that is strikingly deficient in this pathway. This cell variant was induced by selection for growth in stepwise increasing concentrations (up to 10 mM) of the irreversible ODC inhibitor, alpha-difluoromethylornithine (DFMO). Resistance to this inhibitor appears to result from a combination of elevated (10X) ODC biosynthesis and inhibited degradation, producing greater than a 2000-fold increase in the level of ODC protein. In these variant cells (DH23b) inhibition of protein synthesis by cycloheximide did not result in rapid loss of enzyme activity or ODC protein determined by radioimmunoassay. Pulse-chase studies with [35S]methionine confirmed that this enzyme was not preferentially degraded, even when spermidine was added to the media. ODC purified from the variant cells was found to be identical to the control cell enzyme in size, isoelectric point, substrate binding kinetics, and sensitivity to the inhibitor DFMO. Also, as in the control cells, a major fraction of the ODC molecules extracted from DH23b cells was shown to be phosphorylated on a serine residue. The inability to detect physical or kinetic differences between the parent and the variant cell ODC suggests that the unusual stability of ODC in this cell is associated with a defect in a cellular mechanism for ODC-specific degradation.

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