首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Receiver operator characteristic (ROC) techniques were used to determine relative importance of heterogeneity, bone marrow uptake, hepatomegaly, splenomegaly, and focal lesions in the scintigraphic diagnosis of cirrhosis, as well as to determine whether each of the criteria should be used as an identifier (high sensitivity) or as a discriminator (high specificity). Heterogeneity, splenomegaly, and bone marrow uptake were found to be good identifiers of hepatic disease. However, heterogeneity was found to be a poor discriminator for cirrhosis, splenomegaly showed some value as a discriminator, and bone marrow uptake was found to be a reliable discriminator for alcoholic liver disease. The presence of focal lesions was a good discriminator for metastatic disease, and was not specific for cirrhosis. Hepatomegaly also was not specific for cirrhosis. This method of analysis provides a relatively simple method for assembling a hierarchical guide to diagnostic criteria for the interpreting physician.  相似文献   

2.
OBJECTIVES: To assess the value of receiver operating characteristic curves (ROCs) as a tool for improvement in the evaluation of cervicovaginal smear results. DESIGN: We reviewed the results of cervicovaginal smear interpretation for 1 year by 10 different cytopathologists working in the same laboratory (total number of cases, 45,356) and compared them with results of histologic evaluation of corresponding biopsies (n = 2090, 4.6%), the latter taken to be the gold standard. Receiver operating characteristic curves were generated for the laboratory as a whole and for individual cytopathologists. RESULTS: Analysis of these receiver operating characteristic curves was surprisingly informative. They showed that cytopathologists with different diagnostic thresholds could be distinguished from each other. A difference in diagnostic threshold could be distinguished from a difference in diagnostic accuracy. CONCLUSIONS: We conclude that while receiver operating characteristic curves for cervicovaginal smear interpretation have limitations, the results can be used for quality improvement.  相似文献   

3.
Receiver operating characteristic (ROC) analysis was used to evaluate 11 Minnesota Multiphasic Personality Inventory—2 (MMPI—2) indicators of response distortion. College students who chose to simulate malingering or defensive responding were offered a cash incentive for avoiding detection. The responses of malingerers were compared with those of defendants undergoing pretrial evaluation and general psychiatric inpatients. The responses of defensive students were compared with those of students who responded under standard instructions. Area under the ROC curve (AUC) provided the index of discriminative power. In the detection of malingering, F, F – K and, in 1 of 2 comparisons, F(p) produced significantly larger AUCs than other indices. Differences among indicators of defensiveness were generally small. However, the performance of the S scale was promising, whereas F – K performed significantly worse than several other indices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

4.
Individual gastric glands of the stomach are composed of cells of different phenotypes. These are derived from multipotent progenitor stem cells located at the isthmus region of the gland. Previous cell lineage analyses suggest that gastric glands, as in the colon and small intestine, are invariably monoclonal by adult stages. However, little is known about the ontogenetic progression of glandular clonality in the stomach. To examine this issue, we employed an in situ cell lineage marker in female mice heterozygous for an X-linked transgene. We found that stomach glands commence development as polyclonal units, but by adulthood (6 weeks), the majority progressed to monoclonal units. Our analysis suggests that at least three progenitor cells are required to initiate the development of individual gastric glands if they are analyzed just after birth. Hence, unlike the colon and small intestine, stomachs showed a significant fraction (10-25%) of polyclonal glands at adult stages. We suggest that these glands persist from polyclonal glands present in the embryonic stomach and hypothesize that they represent a subpopulation of glands with larger numbers of self-renewing stem cells.  相似文献   

5.
6.
In this taxonomic article we explore the metaphor of comparing a psychiatric classification to a psychological test. Structurally, diagnostic criteria are like test items; diagnostic categories are like scales; and classifications are like tests. Analytically, the ideas of reliability and validity are the primary concepts invoked in the empirical evaluation of both classifications and tests. However, when the metaphor is explored in more detail, the differences between classifications and tests become clear. These differences are discussed in terms of the structural and analytical relations between tests and classifications. This metaphorical analysis of classifications as tests suggests that certain issues that have been discussed in regard to psychological tests, particularly reliability and validity, may require modification when applied to psychiatric classification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

7.
Wechsler Memory Scale—Revised (WMS–R) scores were analyzed in 82 epilepsy surgery candidates. These scores were used in combination with receiver operating characteristic (ROC) curves to classify patients with left temporal lobe (LTL; n?=?47) and right temporal lobe (RTL; n?=?35) seizure onset. Areas under the ROC curves indicated that separation of the LTL and RTL groups with most WMS–R subtest scores was minimal and close to chance level. Analyses of cutting scores revealed modest levels of classification with verbal memory measures such as the Logical Memory II subtest and with a score measuring the difference between Verbal and Visual Memory indexes. The results indicate that WMS–R scores used in isolation or in combination provide relatively poor discrimination of LTL and RTL patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

8.
BACKGROUND AND STUDY AIMS: Chronic atrophic fundic gastritis (CAFG) is associated with several diseases, such as gastric cancer, gastric ulcer, pernicious anemia, and bacterial overgrowth. In spite of recent technical improvements, the gastroscopic diagnosis of CAFG remains uncertain. Congo red chromogastroscopy is capable of visualizing acid-producing normal fundic mucosa, but has hitherto not been suitable for routine use. The aim of our study was to establish a reliable endoscopic technique with which to diagnose CAFG. PATIENTS AND METHODS: This prospective study comprises 124 consecutive patients (71 women, 53 min) with a mean age of 65 years (range 36-92). Macroscopic evaluation of the gastric fundic mucosa in routine endoscopy using video techniques was compared with evaluation by means of a modified endoscopic Congo red test (MCRT). In routine gastroscopy, CAFG was recognized by the thin, friable mucosa, with a marked visible vascular pattern and fold atrophy. With MCRT, the diagnosis of CAFG was made within five minutes' observation when no red-to-blue color shift in the fundic mucosa could be induced by 0.2 mu g/kg intravenous pentagastrin. The results were then compared with the histological examination of biopsies from the fundic mucosa. RESULTS: CAFG was confirmed by histology in 40 of 124 cases. The diagnostic sensitivity of MCRT was 1.0 (40/40), with a positive predictive value of 0.90, whereas the values for macroscopic gastroscopic evaluation were 0.25 (10/40) and 0.50, respectively. CONCLUSIONS: We conclude that MCRT is a sensitive, fast, and cost-effective method of identifying patients with CAFG, and well suited for use in routine gastroscopy.  相似文献   

9.
10.
OBJECTIVES: The effectiveness of upper endoscopy in unselected patients with upper gastrointestinal hemorrhage has not been well studied. This study was undertaken to identify factors associated with the performance of early endoscopy (ie, within 1 day of hospitalization) and, after adjusting for these factors, to determine associations between early endoscopy and in-hospital mortality, length of stay, and performance of surgery. METHODS: Subjects in this observational cohort study were 3,801 consecutive admissions with upper gastrointestinal hemorrhage to 30 hospitals in a large metropolitan region. Demographic and clinical data were abstracted from hospital records. A multivariable model based on factors that potentially could relate to the decision to perform endoscopy was developed to determine the propensity (0 to 100%) for early endoscopy in each patient. RESULTS: Early endoscopy was performed in 2,240 patients (59%), and although it was not associated with mortality after adjusting for severity of illness among all patients, it was associated with a higher risk of death for patients in the lowest propensity group. Early endoscopy was associated with a lower likelihood of upper gastrointestinal surgery in all patients and in the two highest propensity groups and with a shorter length of stay in the entire cohort and in all subgroups. CONCLUSIONS: In the absence of specific contraindications, early endoscopy should be considered because of associated reductions in length of stay and surgical intervention. Further studies are needed to identify subgroups in whom the procedure may be associated with adverse effects on survival.  相似文献   

11.
Possessiveness in mothers of schizophrenics was compared with wives and other female relatives of schizophrenics, and mothers and wives of patients with nonorganic disorders. The results indicated that there was no difference in the quality of possessiveness between the groups studied, rejecting the notion that this is a significant factor in the psychogenesis of schizophrenics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

12.
13.
The gene responsible for X linked agammaglobulinaemia (XLA) lies in Xq22 and has recently been identified as atk. DXS101 is a polymorphic locus which is closely linked to the disease locus. In this report we describe the identification, by pulsed field gel electrophoresis, of a new polymorphism at the DXS101 locus with a predicted heterozygosity of 4.9%. Despite this low value, we show how this polymorphism has been important in carrier status determination in a family with XLA where assessment was not possible by other means.  相似文献   

14.
The clinical features of Cushing's syndrome (such as obesity, hypertension, and diabetes) are commonly encountered in clinical practice. Patients with Cushing's syndrome have been identified by an abnormal low-dose dexamethasone suppression test, elevated urine free cortisol (UFC), an absence of diurnal rhythm of plasma cortisol, or an elevated late-night plasma cortisol. Because the concentration of cortisol in the saliva is in equilibrium with the free (active) cortisol in the plasma, measurement of salivary cortisol in the evening (nadir) and morning (peak) may be a simple and convenient screening test for Cushing's syndrome. The purpose of this study was to evaluate the usefulness of the measurement of late-night and morning salivary cortisol in the diagnosis of Cushing's syndrome. We studied 73 normal subjects and 78 patients referred for the diagnosis of Cushing's syndrome. Salivary cortisol was measured at 2300 h and 0700 h using a simple, commercially-available saliva collection device and a modification of a standard cortisol RIA. In addition, 24-h UFC was measured within 1 month of saliva sampling. Patients with proven Cushing's syndrome (N = 39) had significantly elevated 2300-h salivary cortisol (24.0 +/- 4.5 nmol/L), as compared with normal subjects (1.2 +/- 0.1 nmol/L) or with patients referred with the clinical features of hypercortisolism in whom the diagnosis was excluded or not firmly established (1.6 +/- 0.2 nmol/L; N = 39). Three of 39 patients with proven Cushing's had 2300-h salivary cortisol less than the calculated upper limit of the reference range (3.6 nmol/L), yielding a sensitivity of 92%; one of these 3 patients had intermittent hypercortisolism, and one had an abnormal diurnal rhythm (salivary cortisol 0700-h to 2300-h ratio <2). An elevated 2300-h salivary cortisol and/or an elevated UFC identified all 39 patients with proven Cushing's syndrome (100% sensitivity). Salivary cortisol measured at 0700 h demonstrated significant overlap between groups, even though it was significantly elevated in patients with proven Cushing's syndrome (23.0 +/- 4.2 nmol/L), as compared with normal subjects (14.5 +/- 0.8 nmol/L) or with patients in whom Cushing's was excluded or not firmly established (15.3 +/- 1.5 nmol/L). Late-night salivary cortisol measurement is a simple and reliable screening test for spontaneous Cushing's syndrome. In addition, late-night salivary cortisol measurements may simplify the evaluation of suspected intermittent hypercortisolism, and they may facilitate the screening of large high-risk populations (e.g. patients with diabetes mellitus).  相似文献   

15.
The purpose of this study was to examine the possibility of using Artemia salina as a test organism in the search for compounds having the ability to protect against superoxide-mediated toxicity. The basic procedure for the assay using Artemia salina was performed as described in previous literature, with minor modifications. We found that Artemia salina are extremely sensitive to menadione bisulfite, a compound whose toxicity is probably mediated by intracellular superoxide generation. Desferrioxamine (desferal), a compound with known protective effects, was shown to display dramatic protective activity in our system. We also observed that an inhibitor of endogenous superoxide dismutase (SOD) activity increased the toxicity of menadione toward Artemia salina. In conclusion, this simple, inexpensive, and convenient assay could be a valuable addition to a screening effort in the search for compounds that will be protective against damage by superoxide or other active oxygen species.  相似文献   

16.
Xanthomas may be associated with benign or malignant lymphoproliferative diseases, often with associated hypergammaglobulinema. In human immunodeficiency virus type 1 (HIV-1) disease, there is a high lymphoproliferative rate despite the immunodeficiency and increased cell death. We report three HIV-1-positive patients with facial papular xanthomatosis eruptions associated with hypergammaglobulinema, and an immunoglobulin A (IgA) gammopathy. Histopathologic features include lipid-laden macrophages, extracellular nuclear dust with phagocytosized nuclear debris, and hyalinization with areas of hyaline necrosis of collagen fibers. These distinctive papular xanthomas may be a marker of HIV-1 disease and of a pattern of immunodysregulation, immunodeficiency, and lymphoid proliferation seen in HIV-1 disease.  相似文献   

17.
18.
We report a rare case of gastritis cystica profunda (GCP) accompanied by carcinoma that developed in a 51-year-old Japanese man without antecedent gastric surgery. The polypoid tumor was located in the upper body of the resected stomach. Histologically, it was characterized by herniation of surface epithelium and cystic glands in the submucosa, muscularis propria, and subserosa. Marked chronic atrophic gastritis was found throughout the stomach, and dysplastic epithelia and a few adenocarcinoma cells were found in the deeper parts of the GCP. The Ki-67, p53, and p21WAF1/CIP1 labeling indices for the deeper part of the GCP were higher than those for the superficial parts or the surrounding mucosa, suggesting that both epithelial cell proliferation and p53-dependent p21WAF1/CIP1 expression in DNA-damaged cells, which might be associated with gastritis, are enhanced in line with penetration of glands. The underlying mechanisms might be linked in a chain of factors leading to malignancy.  相似文献   

19.
BACKGROUND: Cancer of the skin may be difficult to diagnose clinically if there are minimal skin findings on examination. OBJECTIVE: To remind physicians that the symptoms of squamous cell carcinoma (SCC) may precede physical signs of the tumor. METHODS: Perineural invasion of SCC was confirmed by histologic examination of surgical specimens. RESULTS: We present two patients whose initial presentation of SCC was facial pain due to extensive perineural invasion. Their diagnoses were delayed until skin lesions eventually became evident months later. CONCLUSION: Early detection can be lifesaving, thus emphasizing the importance of including skin cancer in the differential for facial pain or paresthesia.  相似文献   

20.
The motivation for this paper is to review the status of Hierarchical Task Analysis (HTA) as a general framework for examining tasks, including those for which cognitive task analysis methods might be assumed to be necessary. HTA is treated as a strategy for examining tasks, aimed at refining performance criteria, focusing on constituent skills, understanding task contexts and generating useful hypotheses for overcoming performance problems. A neutral and principled perspective avoids bias and enables the analyst to justify using different analytical methods and develop hypotheses as information is gained about the task. It is argued that these considerations are equally valid when examining tasks that are assumed to contain substantial cognitive elements. Moreover, examining cognition within the context of a broader task helps to situate cognition within the network of actions and decisions that it must support, as well as helping to establish where effort in cognitive task analysis is really justified.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号