20 resultados para Impact of compositional constraints-on correlation and covariance
Resumo:
Vertical integration is grounded in economic theory as a corporate strategy for reducing cost and enhancing efficiency. There were three purposes for this dissertation. The first was to describe and understand vertical integration theory. The review of the economic theory established vertical integration as a corporate cost reduction strategy in response to environmental, structural and performance dimensions of the market. The second purpose was to examine vertical integration in the context of the health care industry, which has greater complexity, higher instability, and more unstable demand than other industries, although many of the same dimensions of the market supported a vertical integration strategy. Evidence on the performance of health systems after integration revealed mixed results. Because the market continues to be turbulent, hybrid non-owned integration in the form of alliances have increased to over 40% of urban hospitals. The third purpose of the study was to examine the application of vertical integration in health care and evaluate the effects. The case studied was an alliance formed between a community hospital and a tertiary medical center to facilitate vertical integration of oncology services while maintaining effectiveness and preserving access. The economic benefits for 1934 patients were evaluated in the delivery system before and after integration with a more detailed economic analysis of breast, lung, colon/rectal, and non-malignant cases. A regression analysis confirmed the relationship between the independent variables of age, sex, location of services, race, stage of disease, and diagnosis, and the dependent variable, cost. The results of the basic regression model, as well as the regression with first-order interaction terms, were statistically significant. The study shows that vertical integration at an intermediate health care system level has economic benefits. If the pre-integration oncology group had been treated in the post-integration model, the expected cost savings from integration would be 31.5%. Quality indicators used were access to health care services and research treatment protocols, and access was preserved in the integrated model. Using survival as a direct quality outcome measure, the survival of lung cancer patients was statistically the same before and after integration. ^
Resumo:
Alzheimer's disease (AD), the most common form of dementia, is the fifth leading cause of death among U.S. adults aged 65 or older. Most AD patients have shorter life expectancy compared with older people without dementia. This disease has become an enormous challenge in the aging society and is also a global problem. Not only do families of patients with Alzheimer's disease need to pay attention to this problem, but also the healthcare system and society as a whole have to confront. In dementia, functional impairment is associated with basic activities of daily living (ADL) and instrumental activities of daily living (IADL). For patients with Alzheimer's disease, problems typically appear in performing IADL and progress to the inability of managing less complex ADL functions of personal care. Thus, assessment of ADLs can be used for early accurate diagnosis of Alzheimer's disease. It should be useful for patients, caregivers, clinicians, and policy planners to estimate the survival of patients with Alzheimer's disease. However, it is unclear that when making predictions of patient outcome according to their histories, time-dependent covariates will provide us with important information on how changes in a patient's status can effect the survival. In this study, we examined the effect of impaired basic ADL as measured by the Physical Self-Maintenance Scale (PSMS) and utilized a multistate survival analysis approach to estimate the probability of death in the first few years of initial visit for AD patients taking into consideration the possibility of impaired basic ADL. The dataset used in this study was obtained from the Baylor Alzheimer's Disease and Memory Disorders Center (ADMDC). No impaired basic ADL and older age at onset of impaired basic ADL were associated with longer survival. These findings suggest that the occurrence of impaired basic ADL and age at impaired basic ADL could be predictors of survival among patients with Alzheimer's disease. ^
Resumo:
This paper synthesizes the current knowledge available regarding the impact of socioeconomic status on diabetes and amputations. In September 2009, searches in the OVID Medline and PubMed databases were performed using keywords associated with race/ethnicity, educational level, insurance status, veteran status, low income, diabetes, and lower extremity amputation. Articles published between 1996 and the search date were used. The pertinent articles were analyzed, summarized, and synthesized. ^ The majority of the articles agreed that African American, American Indian, and Latino minorities experience significantly higher rates of diabetes-related lower extremity amputation (LEA) when compared to whites. Few articles suggested that the disparity experienced by minorities and others of low SES was due to biology; most articles link it to a combination of lower income, lower educational attainment, uninsured or underinsured status, and a greater prevalence of detrimental health behaviors such as smoking. These, in turn, are linked to decreased knowledge of self-care, delayed health care seeking, delayed diagnoses and treatment, discrimination, and low quality health care. Interventions focused on patient education, established regimens of treatment, foot care, and control of diabetes have been shown to be effective, although none have lowered the rate of diabetes-related LEA to rates found in the general population.^
Resumo:
The American Thyroid Association recently classified all MEN2A-associated codons into increasing risk levels A-C and stated that some patients may delay prophylactic thyroidectomy if certain criteria are met. One criterion is a less aggressive family history of MTC but whether families with the same mutated codon have variable MTC aggressiveness is not well described. We developed several novel measures of MTC aggressiveness and compared families with the same mutated codon to determine if there is significant inter-familial variability. Pedigrees of families with MEN2A were reviewed for codon mutated and proportion of RET mutation carriers with MTC. Individuals with MTC were classified as having local or distant MTC and whether they had progressive MTC. MTC status and age were assessed at diagnosis and most advanced MTC stage. For those without MTC, age was recorded at prophylactic thyroidectomy or last follow-up if the patient did not have a thyroidectomy. For each pedigree, the mean age of members without MTC, with MTC, and the proportion of RET mutation carriers with local or distant and progressive MTC were calculated. We assessed differences in these variables using ANOVA and the Fisher’s exact test. Sufficient data for analysis were available for families with mutated codons 609 (92 patients from 13 families), 618 (41 patients from 7 families), and 634 (152 patients from 13 families). The only significant differences found were the mean age of patients without MTC between families with codon 609 and 618 mutations even after accounting for prophylactic thyroidectomy (p=0.006 and 0.001, respectively), and in the mean age of MTC diagnosis between families with codon 618 and 634 mutations even after accounting for symptomatic presentation (p=0.023 and 0.014, respectively). However, these differences may be explained by generational differences in ascertainment of RET carriers and the availability of genetic testing when the proband initially presented.
Resumo:
The BCR-ABL fusion gene is the molecular hallmark of Philadelphia-positive leukemias. Normal Bcr is a multifunctional protein, originally localized to the cytoplasm. It has serine kinase activity and has been implicated in cellular signal transduction. Recently, it has been reported that Bcr can interact with xeroderma pigmentosum group B (XPB/ERCC3)—a nuclear protein active in UV-induced DNA repair. Two major Bcr proteins (p160 Bcr and p130Bcr) have been characterized, and our preliminary results using metabolic labeling and immunoblotting demonstrated that, while both the p160 and p130 forms of Bcr localized to the cytoplasm, the p130 form (and to a lesser extent p160) could also be found in the nucleus. Furthermore, electron microscopy confirmed the presence of Bcr in the nucleus and demonstrated that this protein associates with metaphase chromatin as well as condensed interphase heterochromatin. Since serine kinases that associate with condensed DNA are often cell cycle regulatory, these observations suggested a novel role for nuclear Bcr in cell cycle regulation and/or DNA repair. However, cell cycle synchronization analysis did not demonstrate changes in levels of Bcr throughout the cell cycle. Therefore we hypothesized that BCR serves as a DNA repair gene, and its function is altered by formation of BCR-ABL. This hypothesis was investigated using cell lines stably transfected with the BCR-ABL gene, and their parental counterparts (MBA-1 vs. M07E and Bcr-AblT1 vs. 4A2+pZAP), and several DNA repair assays: the Comet assay, a radioinimunoassay for UV-induced cyclobutane pyrimidine dimers (CPDs), and clonogenic assays. Comet assays demonstrated that, after exposure to either ultraviolet (UV)-C (0.5 to 10.0 joules m −2) or to gamma radiation (200–1000 rads) there was greater efficiency of DNA repair in the BCR-ABL-transfected cells compared to their parental controls. Furthermore, after UVC-irradiation, there was less production of CPDs, and a more rapid disappearance of these adducts in BCR-ABL-bearing cells. UV survival, as reflected by clonogenic assays, was also greater in the BCR-ABL-transfected cells. Taken together, these results indicate that, in our systems, BCR-ABL confers resistance to UVC-induced damage in cells, and increases DNA repair efficiency in response to both UVC- and gamma-irradiation. ^