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At least 703 records · Page 39Linked to original sources
PubMed2006

The role of knowledge and motivation in symptom identification accuracy among schizophrenic patients: application of signal detection theory.

OBJECTIVE: Many people with schizophrenia have poor awareness of their symptoms, a problem that may result from lack of knowledge about their illness and/or unwillingness to acknowledge it. The present study assessed the joint influence of lack of knowledge and motivated denial in schizophrenic patients' low symptom awareness. METHOD: Schizophrenic patients (N = 85) and normal control participants (N = 35) identified psychotic symptoms and general stress symptoms in a symptom checklist. The signal detection theory was applied to assess levels of sensitivity (which would be knowledge-mediated) and judgment biases (which would probably be motivated). RESULTS: Compared with normal control participants, schizophrenic patients had lower sensitivity and greater aversion to classify a symptom as a psychotic symptom. CONCLUSIONS: These findings suggest that both lack of knowledge and motivated denial are involved in schizophrenic patients' low symptom awareness.

Adult↗
PubMed2003

Factors influencing outcomes for breast conservation therapy of mammographically detected malignancies.

OBJECTIVE: To evaluate the importance of surgeon caseload, lesion type, and biopsy type on outcomes in breast conservation therapy (BCT). BACKGROUND: Breast conservation therapy has low rates of morbidity and mortality and is being performed with increasing frequency. Its primary advantage is cosmetic, and the amount of breast tissue resected is the main determinant of cosmetic outcomes. STUDY DESIGN: Two hundred seventeen consecutive patients undergoing breast conservation therapy at Northwestern Memorial Hospital for mammographically detected breast cancer were evaluated. The volume of tissue excised was compared with the volume of the tumor as a ratio. Univariate and multivariate analyses of the relationships between the specimen-to-tumor-volume ratio (STVR) and histologic diagnosis, biopsy type, surgeon caseload, and lesion type were examined. RESULTS: The mean (log scale) STVR was significantly lower when the mammographic lesion was identified as a mass or architectural distortion versus calcifications (p < 0.001 in multivariate analysis). Mean log (STVR) was also decreased for higher-caseload surgeons (p = 0.02). Core biopsy before lumpectomy was associated with significantly increased mean log (STVR) (83 versus 50, p = 0.05) without significantly increasing the rate of negative margins. CONCLUSIONS: Mammographic lesion type and biopsy method were associated with the amount of tissue excised relative to tumor size as measured by STVR. In addition, surgeons with higher caseloads were better able to perform needle localization lumpectomy to negative margins while limiting the volume of normal breast tissue excised.

Analysis of Variance↗
PubMed2002

Women's perceptions of the outcome of weight loss diets: a signal detection approach.

OBJECTIVE: Evolutionary psychology suggests that body shape is as important as body size and that, in women, certain body shapes are considered more attractive, specifically a waist-to-hip ratio (WHR) of about 0.70. Research has shown that the WHR does not change as a result of weight loss diets although it may be that women who diet do not appreciate this. We hypothesized that women would report diet outcomes that included shape change. This was investigated using a signal detection paradigm. METHOD: Two groups of female participants (high and low WHRs) were presented with images with high and low WHRs and were asked to choose images they could resemble through dieting. RESULTS: Both groups of women selected low WHR images as the outcome of their diets, supporting theories of evolutionary psychology. DISCUSSION: We conclude that women in the high WHR group may find adherence to diets problematic because the desired change in shape does not occur.

Adult↗
PubMedDate not supplied

Measurement of bromate in bottled water by high-performance liquid chromatography with post-column flow reactor detection.

The objective of this work was to develop a reliable, rugged high-performance liquid chromatographic (HPLC) method for determination of trace levels of bromate (< 10 micrograms/l) in bottled water. HPLC separation was achieved by ion interaction chromatography using a C-18 reversed-phase column and a mobile phase consisting of methanol/water (20:80, v/v) with tetrabutylammonium acetate as the ion interaction reagent. A post-column reaction based on oxidation of o-dianisidine in acidic solution to a product detected at 500 nm provided selective measurement of the oxidants. The limit of detection and the limit of quantitation were 1 and 3 micrograms/l, respectively. Iodate, chlorite, and nitrite were chromatographically separated from bromate and measured by monitoring the post-column reaction. Chloride and chlorate at levels that might be found in bottled water did not interfere with the determination of bromate. Bromate was detected in bottled waters at concentrations up to 40 micrograms/l.

Bromates↗
PubMed2006

Time-resolved optical tomography using short-pulse laser for tumor detection.

Our objective is to perform a comprehensive experimental and numerical analysis of the short-pulse laser interaction with a tissue medium with the goal of tumor-cancer diagnostics. For a short-pulse laser source, the shape of the output signal is a function of the optical properties of the medium, and hence the scattered temporal optical signal helps in understanding the medium characteristics. Initially experiments are performed on tissue phantoms embedded with inhomogeneities to optimize the time-resolved optical detection scheme. Both the temporal and the spatial profiles of the scattered reflected and transmitted optical signals are compared with the numerical modeling results obtained by solving the transient radiative transport equation using the discrete ordinates technique. Next experiments are performed on in vitro rat tissue samples to characterize the interaction of light with skin layers and to validate the time-varying optical signatures with the numerical model. The numerical modeling results and the experimental measurements are in excellent agreement for the different parameters studied. The final step is to perform in vivo imaging of anesthetized rats with tumor-promoting agents injected inside skin tissues and of an anesthetized mouse with mammary tumors to demonstrate the feasibility of the technique for detecting tumors in an animal model.

Animals↗
PubMed2003

Computer-aided detection (CAD) in screening mammography: sensitivity of commercial CAD systems for detecting architectural distortion.

OBJECTIVE: Computer-aided detection (CAD) algorithms have successfully revealed breast masses and microcalcifications on screening mammography. The purpose of our study was to evaluate the sensitivity of commercially available CAD systems for revealing architectural distortion, the third most common appearance of breast cancer. MATERIALS AND METHODS: Two commercially available CAD systems were used to evaluate screening mammograms obtained in 43 patients with 45 mammographically detected regions of architectural distortion. For each CAD system, we determined the sensitivity for revealing architectural distortion on at least one image of the two-view mammographic examination (case sensitivity) and for each individual mammogram (image sensitivity). Surgical biopsy results were available for each case of architectural distortion. RESULTS: Architectural distortion was deemed present and actionable by a panel of expert breast imagers in 80 views of the 45 cases. One CAD system detected distortion in 22 of 45 cases of distortion (case sensitivity, 49%) and in 30 of 80 mammograms (image sensitivity, 38%); it displayed 0.7 false-positive marks per image. Another CAD system identified distortion in 15 of 45 cases (case sensitivity, 33%) and 17 of 80 mammograms (image sensitivity, 21%); it displayed 1.27 false-positive marks per image. Sensitivity for malignancy-caused distortion was similar to or lower than sensitivity for all causes of distortion. CONCLUSION: Fewer than one half of the cases of architectural distortion were detected by the two most widely available CAD systems used for interpretations of screening mammograms. Considerable improvement in the sensitivity of CAD systems is needed for detecting this type of lesion. Practicing breast imagers who use CAD systems should remain vigilant for architectural distortion.

Adult↗
PubMed2000

Work stressors and alcohol consumption among white-collar workers: a signal detection approach.

OBJECTIVE: Previous findings regarding the relationship between work stress and alcohol consumption are inconsistent and inconclusive. One of the primary reasons for the inconsistency of the findings is that simple models, such as multiple regression analysis or analysis of variance (ANOVA), have been conventionally adopted in studies examining the relationship between work stressors and alcohol consumption. Since higher order interactions of multiple work stressors, which lead to heavy alcohol consumption, might not be fully uncovered within the framework of a multiple regression analysis or ANOVA, another approach to exploring the interactions of work stressors is presented in this study. METHOD: A signal detection analysis method was used to evaluate higher order interactions of work stress variables and to obtain basic information on 465 Japanese male white-collar workers. RESULTS: Of 11 work stressor or work position variables, four significant predictors of heavy alcohol consumption were identified. CONCLUSIONS: Two procedures were successfully performed in this study: (1) evaluating several higher order interactions of work stressors associated with heavy alcohol consumption, and (2) obtaining basic information to permit dividing the subjects into subgroups for further analysis using models and independent variables unique to each subgroup.

Adult↗
PubMed2003

Prospective evaluation of a 21-sample needle biopsy procedure designed to improve the prostate cancer detection rate.

OBJECTIVES: To evaluate prospectively the diagnostic yield of a 21-sample ultrasound-guided needle biopsy procedure for prostate cancer in patients with elevated serum prostate-specific antigen and/or abnormal digital rectal examination findings. METHODS: Between December 2000 and May 2002, 303 patients underwent 21-sample needle biopsy under local anesthesia, comprising sextant biopsies at a 45 degrees angle, 3 biopsies in each peripheral zone at an 80 degrees angle, 3 biopsies in each transition zone (TZ), and 3 biopsies in the midline peripheral zone. Morbidity was assessed clinically. A short questionnaire was filled out by 90 consecutive patients. RESULTS: The cancer detection rate using 6 biopsy samples (sextant biopsies only), 12 samples (sextant plus lateral biopsies), 18 samples (sextant plus lateral plus TZ biopsies), and 21 samples (sextant plus lateral plus TZ, plus midline biopsies) was 22.7%, 28.3%, 30.7%, and 31.3%, respectively. The 21-sample procedure statistically improved the cancer detection rate by 37.9% relative to the 6-sample procedure. The improvement was most marked in patients with a prostate volume of more than 40 cm(3) (48.3%), patients with Stage T1c prostate disease (44.9%), patients undergoing repeat biopsy (66.2%), and patients with prostate-specific antigen levels greater than 10 ng/mL (38.5%). Adverse effects were infrequent (3%), consisting of prostatitis in 3 patients, acute urinary retention in 6 patients, and rectal bleeding requiring hospitalization in 1 patient taking aspirin. Using the questionnaire, 84% of patients reported macroscopic hematuria for an average of 3.4 days and hematospermia for 12.8 days, and 45% reported minor rectal bleeding lasting 1.1 days. The mean pain score, with a visual analog scale ranging between 0 (no pain) and 10 (intense pain), was 4.56. CONCLUSIONS: A 21-sample needle biopsy procedure increased the prostate cancer detection rate relative to a 6-sample procedure, without increasing morbidity. Patients with elevated prostate-specific antigen values should undergo sextant biopsies and at least 6 additional biopsies in the peripheral zone and 6 in the TZ.

Aged↗
PubMed2003

Genetic susceptibility for lung cancer: interactions with gender and smoking history and impact on early detection policies.

OBJECTIVES: To identify a subgroup of former, current and never smokers (males and females) at high risk for developing lung cancer, based on their genetic susceptibility profiles, to estimate their lifetime probabilities of the disease, and to assess the potential mortality reduction that could be achieved by screening the high-risk group. METHODS: Case-control data (764 cases and 677 matched controls), on two assays of DNA damage and repair (mutagen susceptibility and DNA repair capacity, DRC) in different smoking categories were used to obtain estimates of susceptibility using the formula of total probability. The estimates were inserted into a model of lung cancer natural history and detection by screening to assess mortality reduction due to screening of high-risk individuals. RESULTS: The high-risk group was defined as that 12.5% of the population who were above the third quartile for bleomycin sensitivity and below the median for DRC. High-risk male current, former, and never smokers had lifetime probabilities for developing lung cancer of 38, 21, and 5%, respectively. Females had lower probabilities to develop lung cancer: 15, 8, and 1.5% for high-risk current, former, and never smokers, respectively. Screening of high-risk smokers (12.5% of all smokers) reduced overall mortality by 7% compared to 30% reduction if all smokers were screened. Analogous results were obtained for former and never smokers. CONCLUSIONS: Genetic susceptibility constitutes an important factor in the selection of a high-risk group for early lung cancer detection.

Age of Onset↗
PubMed2004

Acanthamoeba keratitis in non-contact lens wearers in India: DNA typing-based validation and a simple detection assay.

OBJECTIVES: To establish that the protozoan Acanthamoeba is one of the causative organisms associated with non-contact lens-related keratitis in the Indian population and to develop a simple and sensitive diagnostic assay for clinical testing. DESIGN: DNA sequencing of nuclear 18S and 26S ribosomal DNA motifs was performed and compared with the reference Acanthamoeba strains, to establish the genetic identity of the putative amoeba isolates obtained from the corneal scrapings of non-contact lens-wearing patients with keratitis. Ribosomal DNA typing of clinical corneal scrapings from the patients with keratitis was performed by means of a simple agarose gel-based multiplex polymerase chain reaction assay, to detect the cases of Acanthamoeba keratitis. RESULTS: The ribosomal DNA analysis of 15 putative amoeba isolates obtained from the corneal scrapings of 14 patients with keratitis and 1 from the patients' environment established the isolates to be pathogenic formsof Acanthamoeba belonging to type T4 ribosomal DNA genotype. Multiplex polymerase chain reaction assay was specific and sensitive enough to detect as low as 5 pg of Acanthamoeba DNA. Its utility as a reliable diagnostic assay was demonstrated directly with the use of 34 additional corneal scrapings. CONCLUSIONS: Acanthamoeba is one of the causative organisms of keratitis in Indian patients with no history of contact lens usage. Moreover, the Acanthamoeba infection can be easily detected in the clinical samples by means of the simple multiplex polymerase chain reaction assay based on ribosomal DNA typing. Clinical Relevance This study suggests the need and means to determine the incidence and prevalance of Acanthamoeba keratitis in India and elsewhere. Moreover, the polymerase chain reaction assay would help in early and definitive diagnosis, leading to better prognosis of Acanthamoeba keratitis condition.

Acanthamoeba↗
PubMed2002

Multifocal objective perimetry in the detection of glaucomatous field loss.

PURPOSE: To test the ability of a new type of multifocal objective perimetry to identify glaucomatous visual field defects. METHODS: A multichannel visual evoked potential was recorded using the ObjectiVision Accumap perimeter. One hundred patients (age, 62.2 +/- 9.8 years, mean MD -6.5 +/- 4.17 dB) with open-angle glaucoma and confirmed glaucomatous visual field defects were tested and compared with the normal database of 100 normal subjects (age, 58.9 +/- 10.7 years). Both eyes were tested, but for determining sensitivity the eye with the lesser field defect was chosen if both qualified. The amplitude and intereye asymmetry coefficient for each zone of the field were calculated. A mean amplitude and multifocal objective perimetry severity index was calculated for each subject. RESULTS: In 95 of 100 (95%) patients with glaucoma Humphrey field defects were correlated with visual evoked potential amplitude reductions identifying a cluster of three or more abnormal zones. In two of five remaining patients with glaucoma the defect was detected on the intereye asymmetry analysis. Topographic location was well correlated with Humphrey fields. Mean amplitude was significantly reduced in 86 of the glaucoma cases (86%). The glaucoma severity index was abnormal in 93 glaucoma cases and showed a correlation with Humphrey MD (r = 0.67 right eyes, 0.69 left eyes). In 37 glaucoma cases with no scotoma by definition in the fellow eye, 22 (59.4%) had an abnormal multifocal objective perimetry, whereas only eight had some other aspect of their Humphrey visual field flagged as abnormal. CONCLUSIONS: Multifocal objective perimetry can assess the visual field and identify glaucomatous visual field defects. It may have the potential for identifying defects earlier than conventional perimetry.

Adult↗
PubMed2002

A more advanced clinical stage is positively correlated with an increased prostate cancer detection rate.

OBJECTIVES: To determine whether an additional subclassification of the assessed clinical stage for prostate cancer before biopsy increases our ability to predict the biopsy outcome. A suspicious digital rectal examination (DRE) and/or a suspicious transrectal ultrasound (TRUS) investigation increases the likelihood of prostate cancer given a certain prostate-specific antigen level. METHODS: Biopsies done in 2199 men with suspicious DRE and/or TRUS findings were studied. The clinical stage was assessed according to the 1992 TNM classification. Univariate and multivariate statistical analyses were performed. RESULTS: The assessed extent of disease classified as intracapsular or extracapsular (ie, clinical Stage T2 versus T3 and T4) was a significant independent predictor for the biopsy outcome. Men with suspected extracapsular disease on the basis of the DRE findings before the sextant biopsy had a twofold increased odds ratio of having prostate cancer detected compared with men with suspected intracapsular disease. A suspicion of extracapsular disease on the basis of TRUS findings, however, significantly decreased the risk of having prostate cancer detected in a biopsy. CONCLUSIONS: We found a modified version of the clinical stage (ie, extracapsular, clinical T3 or T4 cancer versus intracapsular) to be significantly better in predicting the presence of prostate cancer at a given prostate-specific antigen level than a simple "yes or no abnormality found on DRE and/or TRUS" qualification. A suspicion of extracapsular disease raised on the basis of the DRE findings should be valued differently than a similar suspicion raised on the basis of the TRUS findings. Apparently, the extracapsular lesions seen by TRUS are primarily nonmalignant.

Aged↗
PubMed2001

Benign positional vertigo without detectable nystagmus.

OBJECTIVES: To demonstrate that for treatment of benign positional vertigo it is not necessary to identify a positional nystagmus. STUDY DESIGN: Prospective trial of 43 patients with positional vertigo without clinical evidence of positional nystagmus who were treated with a modified canal-repositioning maneuver. METHODS: Results were compared with the results obtained in the treatment of posterior semicircular cupolo-canalithiasis with typical positional nystagmus with the same repositioning maneuver. RESULTS: Treatment of 43 patients with positional vertigo without positional nystagmus resulted in a 60.46% (26/43) complete recovery rate and a 6% (3/43) persistence of disorder rate compared with a 90% complete recovery rate obtained in 90 patients with typical benign positional paroxysmal vertigo (with positional nystagmus). CONCLUSIONS: What is attempted by this work is to confirm that through clinical evaluation based on history and positioning tests alone, one can obtain acceptable results in treatment of supposed canalithiasis without having detected the pathognomonic nystagmus.

Diagnosis, Differential↗
PubMed2005

Malignancy associated changes in epithelial cells of buccal mucosa: a potential cancer detection test.

OBJECTIVE: To analyze the presence of malignancy associated changes (MACs) in normal buccal mucosa cells of lung and breast cancer patients and their relationship to tumor subtype, stage and size. STUDY DESIGN: Buccal mucosa smears of 107 lung cancer and 100 breast cancer patients and corresponding healthy subjects were collected, stained by the DNA-specific Feulgen-thionin method and scanned using an automated high-resolution cytometer. Nuclear texture features of a minimum of 500 nuclei per slide were calculated, and statistical classifiers using Gaussian models of class-probability distribution were designed, trained and tested in 3 parts: (1) ability to separate cancer patient samples from controls, (2) cross-validation of classifiers for different cancer types, and (3) correlation of MAC expression with tumor subtype, stage and size. RESULTS: Lung and breast cancer induce MACs in normal buccal mucosa cells. The classifiers based on the selected nuclear features correctly recognized >80% of lung and breast cancer cases. The results indicate that MAC detection is not dependent on the tumor subtype, stage or size. CONCLUSION: The presence of MACs in buccal mucosa cells offers the potential for developing a new noninvasive cancer screening test.

Adult↗
PubMed1994

Specificity of antenatal ultrasound in the Yorkshire Region: a prospective study of 2261 ultrasound detected anomalies.

OBJECTIVE: To evaluate the specificity of the ultrasound diagnosis of fetal anomalies. Pregnancies which proceeded to termination and ultrasound-diagnosed fetal anomalies which were not offered termination were considered. DESIGN: Prospective, region-wide study over three and a half years. SETTING: Cases were identified through 25 ultrasound departments representing the 15 districts in the Yorkshire Region. SUBJECTS: Pregnant women with an ultrasound-diagnosed fetal anomaly. MAIN OUTCOME MEASURES: Information obtained from the ultrasound report was compared with the outcomes determined by cytogenetics, postmortem or paediatric examination. RESULTS: Of 2261 pregnancies with an ultrasound-diagnosed fetal anomaly 369, (16%) were terminated and 357 (97%) were followed by postmortem examination. Ultrasound findings exactly matched those of the postmortem or were accompanied by additional anomalies in 325 cases (91%). In 32 cases ultrasound findings were not confirmed by postmortem, but in 30 of these the decision to offer termination remained justified because the correct diagnosis was judged equally or more serious. Two (0.5%) were terminated for an anomaly which subsequently proved less severe than predicted on ultrasound. Ultrasound significantly over- or under-diagnosed a major fetal anomaly in 27 of the 1139 (2.4%) cases in which an anomaly was detected, but the pregnancy was not terminated. CONCLUSION: Termination of pregnancy was based on the correct prognosis in over 99.5% of cases. This does not obviate the need for pathological examination of the fetus which changed or refined the diagnosis in 35% of cases.

Abortion, Induced↗
PubMed2004

Condition-specific Western Ontario McMaster Osteoarthritis Index was not superior to region-specific Lower Extremity Functional Scale at detecting change.

OBJECTIVE: We determined whether the sensitivity to change of the Western Ontario McMaster Osteoarthritis Index (WOMAC) physical function (PF) subscale, a condition-specific measure for persons with osteoarthritis of the hip or knee, was superior to a lower extremity region-specific measure, the Lower Extremity Functional Scale (LEFS), in persons with osteoarthritis of the hip or knee undergoing total joint arthroplasty. METHODS: The WOMAC and LEFS were administered to 102 patients with osteoarthritis preoperatively, within 16 days of surgery, and >20 days after the first postoperative assessment. These time points enabled the assessment of deterioration and improvement. Two timed performance measures (40 m walk test and the timed-up-and-go test) were also assessed. Change was quantified by the standardized response mean (SRM). RESULTS: WOMAC PF SRMs were not greater than the LEFS SRMs. Performance measures' times increased significantly over the deterioration interval and decreased over the improvement interval. The WOMAC PF and LEFS demonstrated significant improvement over the second assessment interval; only the LEFS showed significant deterioration over the first assessment interval. WOMAC PF scores seem to be strongly influenced by pain. CONCLUSION: The findings do not support the hypothesis that the WOMAC PF subscale is superior to the LEFS in detecting change.

Aged↗
PubMed1991

Verification of endotracheal tube placement with colorimetric end-tidal CO2 detection.

STUDY OBJECTIVE: To determine the ability of a disposable colorimetric CO2 detector to accurately confirm or refute endotracheal tube placement. DESIGN: Two hundred fifty prospective emergency intubations. SETTING: Emergency intubations performed in the emergency department, helicopter, and prehospital ground environment. TYPE OF PARTICIPANTS: Intubations were performed by emergency medicine residents, paramedics, and flight nurses. INTERVENTIONS: The FEF CO2 detector was applied after 250 emergency intubations. Notation of color change indicating intratracheal placement was recorded in each case. Confirmation of refutation of the detector's results was determined subsequently through traditional methods. RESULTS: The sensitivity for confirmation of endotracheal intubation in the 137 patients with a palpable pulse was 100%. However, only 76 of 103 patients (sensitivity, 72%) in cardiac arrest had endotracheal intubation confirmed by color change. The device was uniformly specific for tracheal intubation in 73 arrested patients in whom a color change was noted (100%). There was one instance (of a total of seven misintubations) in which a positive color change was noted, but the tube was not intratracheal (specificity, 86%). Overall sensitivity for tracheal intubation was 88% (95% confidence limits; range, 0.83 to 0.92), and specificity for tracheal intubation was 92% (95% confidence limits; range, 0.62 to 0.99). CONCLUSION: The FEF colorimetric detector reliably detects intratracheal placement in the nonarrested patient. Its use in prolonged cardiac arrest merits further study.

Breath Tests↗
PubMed2000

Reformulating attention-deficit/hyperactivity disorder according to signal detection theory.

OBJECTIVE: The current diagnostic algorithm for attention-deficit/hyperactivity disorder (ADHD) is not highly predictive of impairment and yields low interrater agreement. The objective of this study was to enhance the diagnostic accuracy of ADHD by identifying the symptoms that are associated with impairment. METHOD: Semistructured interviews and impairment rating scales were administered to parents and teachers of 218 children. Combinations of ADHD symptoms were examined according to a receiver operating characteristic (ROC) based procedure to create diagnostic algorithms that predict impairment. RESULTS: In comparison with the DSM-IV, the ROC-based algorithms were 2 to 3 times more efficient in discriminating impaired from nonimpaired children. Parent and teacher agreement was also 3 times higher. CONCLUSIONS: Limiting the diagnosis to symptoms that predict impairment can increase the validity of the ADHD diagnosis. Results also support the use of ROC analyses in developing better diagnostic algorithms.

Algorithms↗