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排序方式: 共有832条查询结果,搜索用时 15 毫秒
811.
B Mozes MJ Easterling LB Sheiner KL Melmon R Kline ES Goldman AN Brown 《Canadian Metallurgical Quarterly》1994,28(6):689-712
OBJECTIVE: We evaluate the use of routinely gathered laboratory data to subclassify surgical and nonsurgical major diagnostic categories into groups homogeneous with respect to length of stay (LOS). DATA SOURCES AND STUDY SETTING: The source of data is the Combined Patient Experience database (COPE), created by merging data from computerized sources at the University of California San Francisco (UCSF) Medical Center and Stanford University Medical Center for a total sample size of 73,117 patient admissions. STUDY DESIGN: The study is cross-sectional and retrospective. All data were extracted from COPE consecutive admissions; the unit of analysis is an admission. The outcome variable LOS proxies hospital resource utilization for an inpatient stay. Nine (candidate) predictor variables were derived from seven lab tests (WBC, Na, K, C02, BUN, ALB, HCT) by recording the whole-stay minimum or maximum test result. DATA COLLECTION/EXTRACTION METHODS: Patient groups were formed by first assigning to major diagnostic categories (MDCs) all 73,117 admissions. Each MDC was then partitioned into medical and surgical subgroups (sub-MDCs). The 13 sub-MDCs selected for study define a study population of 32,599 patients that represents approximately 45 percent of inpatients. Within each of the 13 sub-MDCs, patients were randomly assigned to one of two data sets in a ratio of 2:1. The first set was used to create, the second to validate, three different LOS predictors. Predictive accuracies of individual DRG classes were compared with those of two alternative classification schemes, one formed by recursive partitioning (the sub-MDC) using only lab test results, the other by partitioning with both lab test results and individual DRGs. PRINCIPAL FINDINGS: For the eight largest sub-MDCs (81 percent of study population), individual DRGs explained 23 percent of the within sub-MDC variance in LOS, laboratory data classes explained 31 percent, and classes derived by considering individual DRGs and laboratory data explained 37 percent. (Each result is a weighted average R2. The average number of LOS classes into which the eight largest sub-MDCs were partitioned were 20, 10, and 10, respectively. Within six of the eight, partitioning on the basis of laboratory data alone explained more within sub-MDC variance than did partitioning into individual DRGs. CONCLUSIONS: Routine lab test data improve the accuracy of LOS prediction over that possible using DRG classes. We note that the improvements do not result from overfitting the data, since the numbers of LOS classes we use to predict LOS are considerably fewer than the numbers of individual DRGs. 相似文献
812.
M Bamshad AE Fraley MH Crawford RL Cann BR Busi JM Naidu LB Jorde 《Canadian Metallurgical Quarterly》1996,68(1):1-28
The aim of the study was to determine the association between PRL responses to suckling and maintenance of postpartum amenorrhea among breastfeeding mothers. Three blood spot samples (5, 30, and 50 min following a timed nursing bout) were collected from 71 intensively breastfeeding Nepali women for PRL determination. Maternal age, BMI (weight/height2), menstrual status, caste, infant age, nursing bout length, and duration of supplementation were recorded at time of sample collection. Independent and paired t tests, linear regression analyses, and general linear models were used to evaluate differences between cycling (n = 36) and amenorrheic (n = 35) women and associations among variables. Logistic regression analyses were used to relate PRL measures to the odds of maintaining lactational amenorrhea. Amenorrheic breastfeeding mothers had higher (P < .001) PRL levels at all 3 collection times than cycling breastfeeding mothers, and PRL levels declined with time since birth (P < 0.05). The odds (OR) of having ceased lactational amenorrhea was significantly higher (OR = 5.0, 95% Cl = 1.3-19.9) among mothers with lower PRL levels (< or = 10 ng/mL) at 50 min post-sucking, and PRL at 50 min showed a significant dose response relationship with menstrual status. The association between 50 min PRL levels and lactational amenorrhea appears to be independent of time postpartum, maternal age, BMI, nursing bout length, and duration of supplementation. Among intensively nursing women, maintenance of elevated PRL levels across the interbout interval increases the odds of maintaining lactational amenorrhea. 相似文献
813.
LB Jacoby M MacCollin DN Louis T Mohney MP Rubio K Pulaski JA Trofatter N Kley B Seizinger V Ramesh 《Canadian Metallurgical Quarterly》1994,3(3):413-419
Family studies and tumor analyses have combined to indicate that neurofibromatosis 2 (NF2), a disorder characterized by multiple benign tumors of the nervous system, and sporadic non-inherited forms of the same tumor types are both caused by inactivation of a tumor suppressor gene located in 22q12. Recently, the gene encoding merlin, a novel member of a family of cytoskeleton-associated proteins, was identified as the NF2 tumor suppressor. To facilitate the search for merlin mutations, we have defined the exon-intron boundaries for all 17 NF2 exons, including one subject to alternative splicing. We have developed polymerase chain reaction assays to amplify each exon from genomic DNA, and used these assays to perform single-strand conformation polymorphism analysis of DNA from 30 sporadic and eight NF2-derived schwannomas, the hallmark tumor type in this disorder. Of a maximum of 60 alleles scanned, 32 showed mutations affecting expression of the merlin protein. Thirty of these mutations are predicted to lead to a truncated protein due to frameshift, creation of a stop codon, or interference with normal splicing, while two are missense mutations. Thus, inactivation of merlin is a common feature underlying both inherited and sporadic forms of schwannoma. 相似文献
814.
815.
816.
The authors present their experience, at the University of Texas Health Science Center at San Antonio, with foot surgery in patients with diabetes mellitus. It is important to note that the results that follow are a reflection of the authors' experience with foot surgery in these patients from 1980 to 1985. The authors report two separate groups of patients: those who underwent elective foot surgery and those who underwent ablative foot surgery for an infected diabetic foot with necrosis. Also reviewed is the etiology of diabetic foot deformities and ulcerations. It has been the authors' experience that elective prophylactic surgery in patients with diabetes and an intact vascular status produces good results. Patients with an infected diabetic foot, providing they demonstrate adequate vascular status, have a high percentage of healing with early surgical intervention. 相似文献
817.
818.
Foreign-body embolization is not an uncommon occurrence. However, to our knowledge, there are only ten reported cases of needle embolization associated with intravenous drug use. We report the sudden death of a 49-year-old white male with a known history of crack cocaine abuse. At autopsy, suspicious needle marks were noted on the right lower extremity. The lungs were of increased weight at 1000 and 1090 g and appeared edematous. The heart weighed 520 g and had a normal red-brown myocardium. Upon sectioning, a broken hypodermic needle of very small caliber was identified in the right ventricular myocardium protruding into the right ventricular chamber. This needle apparently traveled from the injection site to the right ventricle. The right ventricle was dilated and hypertrophied, and microscopic examination showed hyperemic myocardium surrounding the needle. Sections of lung showed numerous foreign-body type giant cells containing polarizable foreign material consistent with intravenous drug use. Toxicological analysis revealed the presence of ethanol (36 mg/dL), cocaine (0.098 mg/L), benzoylecgonine (2.16 mg/L), and morphine (0.841 mg/L). Urine and blood were positive for the presence of 6-monoacetylmorphine. Based on the toxicological analysis, the cause of death was determined to be cocaine and heroin toxicity, and the manner accidental. The needle embolus was considered an incidental finding. 相似文献
819.
Stereoselective bimolecular phenoxy radical coupling by an auxiliary (dirigent) protein without an active center 总被引:1,自引:0,他引:1
LB Davin HB Wang AL Crowell DL Bedgar DM Martin S Sarkanen NG Lewis 《Canadian Metallurgical Quarterly》1997,275(5298):362-366
The regio- and stereospecificity of bimolecular phenoxy radical coupling reactions, of especial importance in lignin and lignan biosynthesis, are clearly controlled in some manner in vivo; yet in vitro coupling by oxidases, such as laccases, only produce racemic products. In other words, laccases, peroxidases, and comparable oxidases are unable to control regio- or stereospecificity by themselves and thus some other agent must exist. A 78-kilodalton protein has been isolated that, in the presence of an oxidase or one electron oxidant, effects stereoselective bimolecular phenoxy radical coupling in vitro. Itself lacking a catalytically active (oxidative) center, its mechanism of action is presumed to involve capture of E-coniferyl alcohol-derived free-radical intermediates, with consequent stereoselective coupling to give (+)-pinoresinol. 相似文献
820.