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991.
992.
RT Osteen DP Winchester DH Hussey RE Clive MA Friedman B Cady JS Chmiel WG Kraybill MM Urist RL Doggett 《Canadian Metallurgical Quarterly》1994,1(6):462-467
BACKGROUND: Trends in the care of patients with cancer are monitored annually by the Commission on Cancer of the American College of Surgeons. In 1991 a patient care evaluation study of breast cancer was conducted, which among other questions examined the correlation of health insurance with type or quality of care delivered for breast cancer on a national basis. METHODS: The tumor registry system of the American College of Surgeons was used to obtain data on patients with breast cancer diagnosed in 1983 and 1990. Trends in diagnosis and treatment were correlated with the type of insurance or lack of insurance. RESULTS: Data were obtained from hospitals in 50 states on a total of 41,651 patients. The largest number of patients were covered by Medicare. Fewer than 5% were considered medically indigent. Medically indigent patients presented with higher stage disease and did not participate in a trend toward downstaging, which occurred between the two study years. The treatment of medically indigent patients appeared to be appropriate and comparable with better insured patients. Insurance type (health maintenance organization vs. private) did not affect stage, treatment, or outcome. Decisions to use controversial therapies, such as chemotherapy for stage I disease, did not appear to be financially driven. CONCLUSION: A nationwide pattern of care study for breast cancer indicates that medically indigent patients present with more advanced disease compared with better insured patients, but once the diagnosis is made, treatment and outcome have little to do with insurance type. 相似文献
993.
P Pushko M Parker GV Ludwig NL Davis RE Johnston JF Smith 《Canadian Metallurgical Quarterly》1997,239(2):389-401
A replicon vaccine vector system was developed from an attenuated strain of Venezuelan equine encephalitis virus (VEE). The replicon RNA consists of the cis-acting 5' and 3' ends of the VEE genome, the complete nonstructural protein gene region, and the subgenomic 26S promoter. The genes encoding the VEE structural proteins were replaced with the influenza virus hemagglutinin (HA) or the Lassa virus nucleocapsid (N) gene, and upon transfection into eukaryotic cells by electroporation, these replicon RNAs directed the efficient, high-level synthesis of the HA or N proteins. For packaging of replicon RNAs into VEE replicon particles (VRP), the VEE capsid and glycoproteins were supplied in trans by expression from helper RNA(s) coelectroporated with the replicon. A number of different helper constructs, expressing the VEE structural proteins from a single or two separate helper RNAs, were derived from attenuated VEE strains Regeneration of infectious virus was not detected when replicons were packaged using a bipartite helper system encoding the VEE capsid protein and glycoproteins on two separate RNAs. Subcutaneous immunization of BALB/c mice with VRP expressing the influenza HA or Lassa virus N gene (HA-VRP or N-VRP, respectively) induced antibody responses to the expressed protein. After two inoculations of HA-VRP, complete protection against intranasal challenge with influenza was observed. Furthermore, sequential immunization of mice with two inoculations of N-VRP prior to two inoculations of HA-VRP induced an immune response to both HA and N equivalent to immunization with either VRP construct alone. Protection against influenza challenge was unaffected by previous N-VRP immunization. Therefore, the VEE replicon system was characterized by high-level expression of heterologous genes in cultured cells, little or no regeneration of plaque-forming virus particles, the capability for sequential immunization to multiple pathogens in the same host, and induction of protective immunity against a mucosal pathogen. 相似文献
994.
Prof. Dr.-Ing. Heinz Ismar cand. ing. Achim Schmitt Dipl.-Ing. Josef Sutor 《Forschung im Ingenieurwesen》1987,53(5):162-168
Zusammenfassung Durch Modifikation wird das Prandtl-Reuss-Modell im elastisch-plastischen übergangsbereich zur Beanspruchungshypothese erweitert.
Die Theorie wird versuchstechnisch verifiziert.
Herrn Professor Dr.Ulrich Gonser zum 65. Geburtstag gewidmet
Der Stiftung Volkswagenwerk danken die Autoren für die Bereitstellung von Sachmitteln. 相似文献
995.
996.
DJ Cohen JA Breall KK Ho RE Kuntz L Goldman DS Baim MC Weinstein 《Canadian Metallurgical Quarterly》1994,89(4):1859-1874
BACKGROUND: Coronary stenting appears to provide more predictable immediate results and lower rates of restenosis than conventional balloon angioplasty for selected lesion types, but its hospital costs are significantly higher. This study was designed to evaluate the potential cost-effectiveness of Palmaz-Schatz coronary stenting relative to conventional balloon angioplasty for the treatment of patients with symptomatic, single-vessel coronary disease. METHODS AND RESULTS: We developed a decision-analytic model to predict quality-adjusted life expectancy and lifetime treatment costs for patients with symptomatic, single-vessel coronary disease treated by either Palmaz-Schatz stenting (PSS) or conventional angioplasty (PTCA). Estimates of the probabilities of overall procedural success (PTCA, 97%; PSS, 98%), abrupt closure requiring emergency bypass surgery (PTCA, 1.0%; PSS, 0.6%), and angiographic restenosis (PTCA, 37%; PSS, 20%) were derived from review of the literature published as of September 1993. Procedural costs were based on the true economic (ie, variable) costs of each procedure at Boston's Beth Israel Hospital. On the basis of these data, coronary stenting was estimated to result in a higher quality-adjusted life expectancy than conventional angioplasty but to incur additional costs as well. Compared with conventional angioplasty, stenting had an estimated incremental cost-effectiveness ratio of $23,600 per quality-adjusted life year gained. Although the cost-effectiveness ratio for stenting changed with variations in assumptions about the relative costs and restenosis rates, it remained less than $40,000 per quality-adjusted year of life gained--and thus was similar to many other accepted medical treatments--unless the stent angiographic restenosis rate was > 23%, the angioplasty restenosis rate was < 34%, or the cost of stenting (including vascular complications) exceeded that of conventional angioplasty by more than $3000. The alternative strategy of secondary stenting (initial angioplasty followed by stenting only for symptomatic restenosis) was estimated to be both less effective and less cost-effective than primary stenting over a wide range of plausible assumptions and thus does not appear to be cost-effective when primary stenting is also an option. CONCLUSIONS: Decision-analytic modeling can be used to evaluate the potential cost-effectiveness of new coronary interventions. Our analysis suggests that despite its higher cost, elective coronary stenting may be a reasonably cost-effective treatment for selected patients with single-vessel coronary disease. Primary stenting is unlikely to be cost-effective for lesions with a low probability of restenosis (eg, < 30%) or for patients for whom the cost of stenting is expected to be much higher than usual (eg, because of a high risk of vascular complications). Given the sensitivity of the cost-effectiveness ratios to even modest variations in the relative restenosis rates and cost estimates, future studies will be necessary to determine more precisely the cost-effectiveness of coronary stenting for specific patient and lesion subsets. 相似文献
997.
IL Smith JM Cherrington RE Jiles MD Fuller WR Freeman SA Spector 《Canadian Metallurgical Quarterly》1997,176(1):69-77
The study describes rates of coronary heart disease death and nonfatal coronary events over five years in a cohort of random sample population and relates them to levels of three major risk factors. It is based on a longitudinal follow-up of survey conducted initially in 1990 in all geographic regions of Turkey. Two-thirds of the original cohort aged 20 years or over 2259 adults comprising 1146 women was followed up by physical examination and an ECG recording at rest. New coronary events were defined to include myocardial infarction and stable angina with or without associated myocardial ischemia developed during the follow-up period. Overall annual death rate was nine per 1000 adults. Coronary deaths numbered 55 (of which 26 were women) representing 4.1 per year and were found high in women. New coronary events were registered in 37 men and 32 women (annual rates 7.2 and 5.8 per 1000, respectively). Among male participants aged initially 40 years or over, high systolic blood pressure (> or = 130 mmHg) at baseline significantly predicted coronary death (age-adjusted risk ratio (RR) 3.3) while high cholesterol concentrations (> or = 5.2 mmol l-1) predicted new coronary events alone (RR almost 2). In women systolic pressure again strongly predicted coronary death (age-adjusted RR 3.9), whereas abnormal cholesterol levels discriminated for coronary death and new coronary events (RR around 2.3 for each). High diastolic pressure (> or = 85 mmHg) was of predictive value for the combined outcome of coronary death and events in women (RR 1.9) but not in men. Multivariate analysis by logistic regression identified systolic blood pressure in men as significant independent predictor of coronary death, while total cholesterol concentration in both genders and systolic blood pressure in men were independent predictors of the combined outcome of coronary death or nonfatal coronary events. It was concluded that known major risk factors act in similar magnitudes commensurate with the specific risk increments also in populations with essentially low cholesterol levels. The relatively high coronary morbidity and mortality in Turkish women approaching that in men may be accounted for by an inherent greater risk burden. 相似文献
998.
RM Aigner RE O'Mara GF Fueger K Tscheliessnigg R Nicoletti E Sorantin EM Smith 《Canadian Metallurgical Quarterly》1998,39(12):2153-2158
In patients with ischemic cardiomyopathy (CM), abnormal renograms may result not only from circulatory failure (which should reverse after transplantation) but also from intrinsic renal disease (which contraindicates heart transplantation). Here, the outcome of heart transplantation was related to preoperative renograms, and the differentiating and prognostic value of renography was analyzed. METHODS: The study population consisted of 50 patients with ischemic CM expecting heart transplantation. Anatomical renal pathology was excluded in all patients. Dynamic renal scintigraphy was performed with 99mTc-mercaptoacetyltriglycine. Background-subtracted renograms were inspected visually and characterized numerically. Mean parenchymal transit time (mPTT), renal tracer content at 15 min (RTC15) and retention index (RI) were determined. The parametric renogram values were related to a normal reference group of 64 patients. The preoperative renograms were matched with the postoperative outcome. RESULTS: Three characteristic types of symmetrical findings in the kidneys were found: no pathological findings, mildly delayed peak and excretion phase and severely delayed peak and excretion phase. Pathological renograms were observed in 36 of 50 (72%) patients. The mean parametric renogram values in ischemic CM were as follows: Group A (normal kidney function), mPTT = 142+/-26.6 sec, RTC15 = 22.3%+/-4.6% and RI = 24.7+/-11.9; Group B (mild dysfunction), mPTT = 210+/-44.0 sec, RTC15 = 42.6%+/-10.3% and RI = 101.4+/-50.5; Group C (severe dysfunction), mPTT = 320+/-94.2 sec, RTC15 = 79.6%+/-15.9% and RI = 347.7+/-194.7; and reference patients (normal kidney function), mPTT = 137+/-31.1 sec, RTC15 = 22.8%+/-3.8% and RI = 24.6+/-7.9. Postoperative serum creatinine levels were <1.5 mg/dl in all Group A patients, between 1.5 and 2.5 mg/dl in 78% of Group B patients and >2.5 mg/dl in 75% of Group C patients. CONCLUSION: Renography revealed abnormal kidney function when structural pathology was excluded. The renographic abnormalities in ischemic CM did not reflect simply the circulatory failure. The numerical grading of renograms allowed patient stratification, suggestive of possible renal insufficiency after cardiac transplantation and immunosuppressive therapy. With further experience, renography may become a useful tool for predicting postoperative outcome in ischemic CM. 相似文献
999.
Dual diagnosis: a review of etiological theories 总被引:1,自引:0,他引:1
The etiology of the high prevalence of substance use disorders in patients with severe mental illness (schizophrenia or bipolar disorder) is unclear. We review the evidence of different theories of increased comorbidity, organized according to four general models: common factor models, secondary substance use disorder models, secondary psychiatric disorder models, and bidirectional models. Among common factor models, evidence suggests that antisocial personality disorder accounts for some increased comorbidity. Among secondary substance use disorder models, there is support for the supersensitivity model, which posits that biological vulnerability of psychiatric disorders results in sensitivity to small amounts of alcohol and drugs, leading to substance use disorders. There is minimal support for the self-medication model, but the accumulation of multiple risk factors related to mental illness, including dysphoria, may increase the risk of substance use disorder. Secondary psychiatric disorder models remain to be convincingly demonstrated. Bidirectional models have not been systematically examined. Further clarification of etiologic factors, including the identification of subtypes of dual diagnosis, may have implications for developing more effective prevention efforts and treatment. 相似文献
1000.
The purpose of this review is to compare several modalities available for detection of coronary artery disease (CAD). We compare the clinical history, rest/exercise electrocardiogram (ECG), rest/stress left ventricular (LV) function by radionuclide or echocardiographic methods, myocardial perfusion imaging (MPI) by single photon emission computed tomography (SPECT) or positron emission tomography (PET), contrast coronary angiography, magnetic resonance imaging (MRI), spectroscopy (MRS) and angiography (MRA), and ultrafast cine computed tomography (UFCT) to assess LV function, myocardial perfusion, and coronary calcification. We compare the modalities by answering six questions: (1) Does the modality provide unique clinical information? (2) What is the observer error? (3) What are sensitivities and specificities to detect CAD? (4) What patient selection criteria should be applied for each modality? (5) What incremental benefit is obtained from one modality versus another modality? and (6) Where do the modalities fit in the overall scheme of diagnostic testing for CAD? PET MPI appears to be the best noninvasive test for CAD, followed by SPECT thallium-201 and then dobutamine echocardiography. MRA and UFCT may soon play a larger role because they visualize the arteries. Contrast coronary angiography remains the gold standard despite its limitations. Exercise ECG is the least accurate test. The choice of tests critically depends on patient selection--based on clinical history, age, gender, and risk factors to estimate the pretest, clinical probability of CAD. 相似文献