Biomedical subjects

J C Lenel

Publications and source records attributed to J C Lenel.

9 recordsLinked to original sources

PubMed1996

Low-grade transitional cell carcinoma of the urinary bladder: application of select cytologic criteria to improve diagnostic accuracy [corrected].

The cytologic diagnosis of low-grade transitional cell carcinoma of the bladder is difficult, and the reported sensitivity of a positive diagnosis ranges from 0 to 73%. Using regression analysis, our laboratory previously reported the criteria of increased nuclear/cytoplasmic ratios, irregular nuclear membranes, and cytoplasmic homogeneity as indicative of low-grade transitional cell carcinoma. To examine the validity of these criteria, six observers examined 88 bladder-wash specimens (39 transitional cell carcinomas and 49 benign) and, using the selected criteria, graded each wash for the probability of malignancy. Diagnostic accuracy was measured using the receiver operating characteristic curve and the likelihood ratio. Overall observer accuracy was 76%, the sensitivity of a definitive negative diagnosis was 82%, and the specificity of a definitive positive diagnosis was 96%. We conclude that key cytologic criteria can be learned and effectively applied with high accuracy. Observer variation in diagnostic categories might reflect different confidence levels and probabilities of transitional cell carcinoma.

Carcinoma, Transitional Cell↗

PubMed1995

p53 protein overexpression in smooth muscle tumors of the uterus.

p53 is a nuclear phosphoprotein whose overexpression may portend a poor prognosis in a variety of neoplasms. In this immunohistochemical study we examined p53 overexpression in a variety of uterine smooth muscle tumors (34 leiomyosarcomas, 18 leiomyomas, and six smooth muscle tumors of uncertain malignant potential [STUMPs]). p53 immunoreactivity was observed in none of 18 (0%) leiomyomas, one of six (17%) STUMPs, and 16 of 34 (47%) leiomyosarcomas. Reactivity was not observed in the surrounding nonneoplastic uterine smooth muscle. Strong p53 overexpression in the leiomyosarcomas was significantly associated with high grade morphology (P = .013) and a high stage at the time of presentation (P = .021). In 25 leiomyosarcoma patients with clinical follow-up, p53 overexpression was associated with shorter length of survival (P = 0.024). However, this effect was not independent of tumor stage or grade. A regression analysis showed that tumor stage was the only independent predictor of length of survival. Our study size is small, and further studies are warranted to determine the significance and replicability of these findings.

Female↗

PubMed1995

Pathology and probability. Likelihood ratios and receiver operating characteristic curves in the interpretation of bronchial brush specimens.

Diagnoses in pathology often are qualitative, such as atypical or suspicious, and consequently are thought to have limited clinical value. To investigate the utility of a qualitative diagnostic system, seven pathologists retrospectively evaluated 100 bronchial brush specimens using the following categories: definitely benign, probably benign, possibly malignant, probably malignant, and definitely malignant. The likelihood ratio (LR) and receiver operating characteristic (ROC) curve, two statistical probabilistic measurements, were used to calculate diagnostic accuracy among individuals and groups. The results show: (1) the LR for individual diagnostic categories varied among observers, resulting in different clinically malignant probabilities; (2) observer experience did not appear to play a role in overall diagnostic accuracy, except in the diagnosis of small cell carcinoma; (3) observers operate at higher levels of diagnostic accuracy with, rather than without, clinical history. The authors conclude that qualitative diagnoses contain important information and can be interpreted effectively with LR and ROC.

Bronchi↗

PubMed1995

Atypical glandular cells of undetermined significance. Cytologic criteria to separate clinically significant from benign lesions.

Histologic follow-up of the cervical-vaginal smear diagnosis of atypical glandular cells of undetermined significance (AGUS) shows a broad spectrum of clinically significant (preneoplastic or neoplastic) and benign lesions. There are few statistical studies that have attempted to separate these AGUS categories based on select cytologic criteria. The authors retrospectively reviewed 116 AGUS without concurrent squamous dysplasia smears (66 clinically significant and 50 benign lesions), and used logistic regression analysis to identify the cytologic criteria of irregular nuclear membranes, atypical single cells, and decreased cytoplasm as useful in separating clinically significant from benign lesions. Using contingency tables, these criteria in combination had a sensitivity 29% and a specificity of 94% in the diagnosis of clinically significant lesions. If any single criterion was present, the sensitivity and specificity were 100% and 28%, respectively. In conclusion, by using key cytologic criteria, a percentage of benign AGUS lesions can be separated from clinically significant AGUS lesions.

Diagnosis, Differential↗

PubMed1994

Low grade transitional cell carcinoma of the bladder. Cytologic diagnosis by key features as identified by logistic regression analysis.

BACKGROUND: Bladder cytology is being used increasingly to detect and monitor early stage bladder cancer. Because of the lack of significant cytomorphologic atypia in low grade transitional cell carcinomas (TCCs), there often is great difficulty in separating these neoplastic cells from benign urothelial cells. METHODS: In an attempt to increase diagnostic sensitivity, 82 bladder wash specimens, which included 33 low grade TCCs and 49 nonneoplastic lesions, were reviewed retrospectively. With a stepwise logistic regression analysis, three key cytomorphologic criteria useful in the separation of low grade TCC from benign urothelium were identified. RESULTS: The key cytologic criteria were increased nuclear/cytoplasmic ratios, irregular nuclear borders, and cytoplasmic homogeneity. By using contingency tables, these three criteria combined had a sensitivity of 45% and a specificity of 98% in the diagnosis of low grade transitional cell carcinoma. If any two of the criteria were present, there was a sensitivity of 85% and a specificity of 96%. CONCLUSIONS: By using these three criteria, the diagnosis of TCC can be made with a high degree of accuracy in bladder wash specimens.

Adult↗

PubMed1984

Measures of displacement and type of background in apparent motion with random-dot cinematograms.

The primary purpose of the studies presented was to determine whether stimulus displacement in random-dot cinematogram apparent motion should be measured in terms of relative or absolute distance, while taking into account the effect of number of displaced elements. Support for each measure has been reported in the literature (Braddick, 1974; Lappin & Bell, 1976). A secondary purpose was to test a basic assumption about the generalizability of results in the random-dot cinematogram literature by determining whether the same results may be obtained using cinematograms with a constant-background field as with cinematograms with a varied-background field. For varied-background cinematograms, the clarity of apparent motion decreased as relative displacement increased. The number of elements in the target square was also found to affect the ratings. These findings support a global rather than strictly local process for perceptually segregating areas of random-dot texture based upon motion. For constant-background cinematograms, factors different from those affecting varied-background cinematograms determined the clarity of apparent motion.

Discrimination Learning↗

PubMed1983

Objects in the path of apparent motion.

Experiments by several investigators suggest that forms between inducing stimuli for apparent motion may deflect motion from a straight path. In an experiment in which a binocularly viewed object was sometimes positioned between the inducing dots, we discovered that the degree of curvature of the path that is most likely to be reported depends upon the interstimulus interval whether or not the space between inducing dots contains an object. The interstimulus interval at which motion is most frequently reported is longer for curved paths of motion than for linear paths even though the spatial separation of inducing stimuli is held constant. The results suggest that apparent motion in depth is not based upon form.

Humans↗

PubMed1981

Dimensions of figural identity and apparent motion.

Warren proposed that for apparent motion to be perceived between disparate shapes, the shapes must be identifiable as the same object. When disparate shapes are seen as different views of the same rigid form, they are called ecologically transformable. Ecological transformability seemed to be the crucial variable in Warren's results. However, Warren's findings conflict with those of Kolers and Pomerantz, who obtained frequent reports of apparent motion of disparate, non-transformable shapes. This discrepancy may be due to the response categories used in Warren's experiment. Warren asked subjects to report whether they saw one or two objects and did not directly assess the perception of motion. We replicated Warren's experiment using his figures but also asked subjects to rate the smoothness of motion and to describe the type of motion. We obtained frequent reports of motion of disparate, nontransformable figures. Surprisingly, after making this correction in Warren's experiment, we also found that transformability as well as "featural similarity" can affect the type and smoothness of the illusory motion.

Discrimination Learning↗

PubMedDate not supplied

Bone tumor radiograph review by pathologists prior to pathologic diagnosis: a receiver operator curve analysis of diagnostic utility.

Radiologic-pathologic correlation has long been considered a prerequisite for the accurate diagnosis of bone lesions. We investigated using receiver-operating characteristic analysis the accuracy of histopathologic diagnoses with and without pathologist review of radiographs. While accuracy of diagnosis did improve when the radiographs were reviewed by the pathologist, this increase did not reach statistical significance (P=0.1311). Potential reasons for this finding including case selection and reviewer expertise are discussed. Based on our study, the review of radiographs did not result in a statistically significant difference in accuracy of the pathologic diagnosis of bone tumors. However, our data suggest that there may be a difference particularly in selected cases and among certain observers.

Bone Neoplasms↗