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31.
Urban-rural hospital affiliations are an outgrowth of both the external pressures on rural hospitals to survive and the need for urban hospitals to maintain or increase their share of the tertiary referral market. This article discusses the significant role of stakeholders in these affiliations, develops a fourfold typology of urban-rural hospital affiliations based on the notions of organizational control and fit, suggests four generic strategies for forming affiliations, and analyzes four actual cases of affiliation. 相似文献
32.
33.
K P Cantor A Blair G Everett S VanLier L Burmeister F R Dick R W Gibson L Schuman 《American journal of public health》1988,78(5):570-571
Data from a population-based case-control study of incident leukemia and non-Hodgkin's lymphoma among adult men in Iowa and Minnesota were used to evaluate risk associated with hair dye use. The relative risk for ever using hair dyes was 1.8 (95% confidence interval [CI] = 1.1-2.7) among leukemia patients, and 2.0 (CI = 1.3-3.0) among cases with non-Hodgkin's lymphoma. There was a suggestion of increased risk with extent of hair dye use. Given the widespread use of hair coloring products, these observations deserve more detailed evaluation in populations where the exposure is relatively common. 相似文献
34.
35.
The parkinsonism that occurs in some patients with olivopontocerebellar atrophy (OPCA) can cause diagnostic confusion with idiopathic Parkinson's disease (IPD). The response to levodopa is usually a distinguishing feature, the OPCAs either failing to benefit or losing efficacy relatively quickly. A fluctuating response to levodopa in those OPCA patients who do benefit has not been emphasized in the literature previously. Reported here are three patients with presumed OPCA, dominated by parkinsonian features, who eventually developed typical fluctuations with morning akinesia, wearing off, and periodic lack of response related to meals. These fluctuations were a major source of disability and an important reason for diagnostic confusion with IPD. The possible mechanisms of these fluctuations are discussed. 相似文献
36.
Social learning theory-based models have recently provided the foundation for a series of twelve controlled human immunodeficiency virus (HIV) risk reduction intervention studies that have examined sexual behavior change. These interventions have been tested with adolescents, gay and bisexual men, inner-city women, college students, and seriously mentally ill adults. We report the first meta-analysis of these intervention studies. We found that, as expected, the mean weighted effect of HIV-risk reduction interventions on behavioral outcomes was positive and strongly significant (d+=0.25). Moreover, the studies’ effect sizes were consistently positive, ranging from 0.11 to 0.53, and were largest when the outcomes were measured close in time to the intervention. We discuss other methodological challenges that, if solved, should enhance the success of future HIV-risk reduction interventions. 相似文献
37.
38.
Louise A. Rollins-Smith Patrick J. Blair A. Tray Davis 《Clinical & developmental immunology》1992,2(3):207-213
Metamorphosis in amphibians presents a unique problem for the developing immune
system. Because tadpoles are free-living, they need an immune system to protect against
potential pathogens. However, at metamorphosis, they acquire a variety of new adultspecific
molecules to which the tadpole immune system must become tolerant. We
hypothesized that Xenopus laevis tadpoles may avoid potentially destructive antiself
responses by largely discarding the larval immune system at metamorphosis and
acquiring a new one. By implanting triploid (3N) thymuses into diploid (2N) hosts, we
examined the influx and expansion of host T-cell precursors in the donor thymus of
normally metamorphosing and metamorphosis-inhibited frogs. We observed that donor
thymocytes are replaced by host-derived cells during metamorphosis, but inhibition of
metamorphosis does not prevent this exchange of cells. The implanted thymuses export
T cells to the spleen. This donor-derived pool of cells declines after metamorphosis in
normally developing frogs but is retained to a greater extent if metamorphosis is
inhibited. These studies confirm previous observations of a metamorphosis-associated
wave of expansion of T cells and demonstrate that it is not dependent on the relatively
high concentrations of thyroid hormones required for metamorphosis. Although some
larval T cells persist through metamorphosis, others may be destroyed or the larval
population is significantly diluted by the expanding adult population. 相似文献
39.
40.
Pulmonary seed embolization is frequently observed in permanent prostate brachytherapy. Postoperative chest radiographic examination does not always detect seed embolization. To overcome this deficiency, a low energy gamma scintillation survey meter was converted to a seed-migration detector by adding a cone-shaped single-hole collimation cap to the window end of the scintillation probe. The response functions of the seed-migration detector to iodine-125 (I-125) for different source-to-detector distances in air and in water were measured. The spatial discrimination power of the survey meter, represented by the full width at half maximum measured in water, is typically improved from more than 7 cm to about 3 cm. Seventy-nine patients with I-125 implantation were scanned with the seed-migration detector at the patients' 30-day postevaluation visit. Fifteen patients showed single-seed embolization to the chest region and four patients displayed two-seed embolization. In other words, 24% of the patients present with embolized seeds. The detection accuracy of each patient was validated by a comprehensive investigation procedure. The comprehensive investigation consists of reviewing the patient's treatment history, orally questioning the patient for possible seed loss via the urethra route outside the hospital, examining all available chest radiographs before and after the seed implantation, and counting the seeds on the postevaluation CT scans. In comparison, examinations relying only on the analysis of postoperative chest radiographs yielded a false-positive detection in four patients and a false-negative detection in two patients. Another advantage of the seed-migration detector is that multiple seed-migration scans can be performed without exposing the patient to any additional radiation, for this device is a passive detector. Our clinical implementation also demonstrated that the seed-migration detector is a convenient and cost-effective method. As a result of this study, we stopped ordering the postoperative chest radiographs in a patient's regular postevaluation visit. Only if the detector shows radioactivity outside a patient's pelvis are a pair of anteroposterior and lateral chest radiographs of the patient ordered to document the location of the embolized seeds. 相似文献