Rational sequence of tests for pancreatic function.
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Of 144 patients with suspected pancreatic disease in whom a 75Se-selenomethionine scan was performed, endoscopic retrograde pancreatography (ERP) was successful in 108 (75%). The final diagnosis is known in 100 patients and has been compared with scan and ERP findings. A normal scan reliably indicated a normal pancreas, but the scan was falsely abnormal in 30%. ERP distinguished between carcinoma and chronic pancreatitis in 84% of cases but was falsely normal in five patients with pancreatic disease. In extrahepatic biliary disease both tests tended to give falsely abnormal results. A sequence of tests to provide a rapid and reliable assessment of pancreatic function should be a radio-isotope scan, followed by ERP if the results of the scan are abnormal, and a Lundh test if the scan is abnormal but the findings on ERP are normal. (+info)
Defining and analysing symptom palliation in cancer clinical trials: a deceptively difficult exercise.
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The assessment of symptom palliation is an essential component of many treatment comparisons in clinical trials, yet an extensive literature search revealed no consensus as to its precise definition, which could embrace relief of symptoms, time to their onset, duration, degree, as well as symptom control and prevention. In an attempt to assess the importance of these aspects and to compare different methods of analysis, we used one symptom (cough) from a patient self-assessment questionnaire (the Rotterdam Symptom Checklist) in a large (>300 patient) multicentre randomized clinical trial (conducted by the Medical Research Council Lung Cancer Working Party) of palliative chemotherapy in small-cell lung cancer. The regimens compared were a two-drug regimen (2D) and a four-drug regimen (4D). No differences were seen between the regimens in time of onset of palliation or its duration. The degree of palliation was strongly related to the initial severity: 90% of the patients with moderate or severe cough at baseline reported improvement, compared with only 53% of those with mild cough. Analyses using different landmark time points gave conflicting results: the 4D regimen was superior at 1 month and at 3 months, whereas at 2 months the 2D regimen appeared superior. When improvement at any time up to 3 months was considered, the 4D regimen showed a significant benefit (4D 79%, 2D 60%, P = 0.02). These findings emphasize the need for caution in interpreting results, and the importance of working towards a standard definition of symptom palliation. The current lack of specified criteria makes analysis and interpretation of trial results difficult, and comparison across trials impossible. A standard definition of palliation for use in the analysis of clinical trials data is proposed, which takes into account aspects of onset, duration and degree of palliation, and symptom improvement, control and prevention. (+info)
Computerized analysis of abnormal asymmetry in digital chest radiographs: evaluation of potential utility.
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The purpose of this study was to develop and test a computerized method for the fully automated analysis of abnormal asymmetry in digital posteroanterior (PA) chest radiographs. An automated lung segmentation method was used to identify the aerated lung regions in 600 chest radiographs. Minimal a priori lung morphology information was required for this gray-level thresholding-based segmentation. Consequently, segmentation was applicable to grossly abnormal cases. The relative areas of segmented right and left lung regions in each image were compared with the corresponding area distributions of normal images to determine the presence of abnormal asymmetry. Computerized diagnoses were compared with image ratings assigned by a radiologist. The ability of the automated method to distinguish normal from asymmetrically abnormal cases was evaluated by using receiver operating characteristic (ROC) analysis, which yielded an area under the ROC curve of 0.84. This automated method demonstrated promising performance in its ability to detect abnormal asymmetry in PA chest images. We believe this method could play a role in a picture archiving and communications (PACS) environment to immediately identify abnormal cases and to function as one component of a multifaceted computer-aided diagnostic scheme. (+info)
Brightness alters Heidelberg retinal flowmeter measurements in an in vitro model.
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PURPOSE: The Heidelberg Retinal Flowmeter (HRF), a laser Doppler flowmetry device, has captured interest as a research and clinical tool for measurement of ocular blood flow. Concerns remain about the range and accuracy of the values that it reports. METHODS: An in vitro blood-flow model was constructed to provide well-controlled laminar flow through a glass capillary for assessment by HRF. A change in material behind the glass capillary was used to simulate changing brightness conditions between eyes. RESULTS: Velocities reported by the HRF correlated linearly to true velocities below 8.8 mm/sec. Beyond 8.8 mm/sec, HRF readings fluctuated randomly. True velocity and HRF reported velocities were highly correlated, with r = 0.967 (P < 0.001) from 0.0 mm/sec to 2.7 mm/sec mean velocity using a light background, and r = 0.900 (P < 0.001) from 2.7 mm/sec to 8.8 mm/sec using a darker background. However, a large change in the y-intercept occurred in the calibration curve with the background change. CONCLUSIONS: The HRF may report velocities inaccurately because of varying brightness in the fundus. In the present experiment, a darker background produced an overreporting of velocities. An offset, possibly introduced by a noise correction routine, apparently contributed to the inaccuracies of the HRF measurements. Such offsets vary with local and global brightness. Therefore, HRF measurements may be error prone when comparing eyes. When used to track perfusion in a single eye over time, meaningful comparison may be possible if meticulous care is taken to align vessels and intensity controls to achieve a similar level of noise correction between measurements. (+info)
Improved methods using the reverse transcriptase polymerase chain reaction to detect tumour cells.
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Reverse transcriptase polymerase chain reaction (RT-PCR) is increasingly used to detect small numbers of circulating tumour cells, though the clinical benefit remains controversial. The largest single contributing factor to the controversy of its value is the different approaches to sample processing. The aim of this study was to compare the sensitivity and reproducibility of RT-PCR for the detection of tumour cells after four commonly used different methods of sample processing. Using RT-PCR, one tumour cell spiked in 2 ml of whole blood was detected after analysis of separated mononuclear cell RNA, whole blood total or poly-A+ RNA. No false positives were identified with any method. However, the reproducibility of tumour cell detection was reduced after isolation of the mononuclear cell fraction. Only analysis of poly-A+ RNA had a sensitivity of 100% in all the cell spiking experiments. In patient blood samples, analysis of poly-A+ RNA increased the number of blood samples positive for tyrosine hydroxylase (TH) mRNA compared with those positive after analysis of total RNA. This may reflect high levels of cDNA reducing the efficiency of the PCR. Isolation of poly-A+ RNA increases the sensitivity and reproducibility of tumour cell detection in peripheral blood. (+info)
Extensive cross-contamination of specimens with Mycobacterium tuberculosis in a reference laboratory.
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A striking increase in the numbers of cultures positive for Mycobacterium tuberculosis was noticed in a mycobacterial reference laboratory in Campinas, Sao Paulo State, Brazil, in May 1995. A contaminated bronchoscope was the suspected cause of the increase. All 91 M. tuberculosis isolates grown from samples from patients between 8 May and 18 July 1995 were characterized by spoligotyping and IS6110 fingerprinting. Sixty-one of the 91 isolates had identical spoligotype patterns, and the pattern was arbitrarily designated S36. The 61 specimens containing these isolates had been processed and cultured in a 21-day period ending on 1 June 1995, but only 1 sample was smear positive for acid-fast bacilli. The patient from whom this sample was obtained was considered to be the index case patient and had a 4+ smear-positive lymph node aspirate that had been sent to the laboratory on 10 May. Virtually all organisms with spoligotype S36 had the same IS6110 fingerprint pattern. Extensive review of the patients' charts and investigation of laboratory procedures revealed that cross-contamination of specimens had occurred. Because the same strain was grown from all types of specimens, the bronchoscope was ruled out as the outbreak source. The most likely source of contamination was a multiple-use reagent used for specimen processing. The organism was cultured from two of the solutions 3 weeks after mock contamination. This investigation strongly supports the idea that M. tuberculosis grown from smear-negative specimens should be analyzed by rapid and reliable strain differentiation techniques, such as spoligotyping, to help rule out laboratory contamination. (+info)
Introduction of appendiceal CT: impact on negative appendectomy and appendiceal perforation rates.
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OBJECTIVE To evaluate the impact of appendiceal computed tomography (CT) availability on negative appendectomy and appendiceal perforation rates. SUMMARY BACKGROUND DATA: Appendiceal CT is 98% accurate. However, its impact on negative appendectomy and appendiceal perforation rates has not been reported. METHODS: The authors reviewed the medical records of 493 consecutive patients who underwent appendectomy between 1992 and 1995, 209 consecutive patients who underwent appendectomy in 1997 (59% of whom had appendiceal CT), and 206 patients who underwent appendiceal CT in 1997 without subsequent appendectomy. RESULTS: Before appendiceal CT, 98/493 patients (20%) taken to surgery had a normal appendix. After CT availability, 15/209 patients (7%) taken to surgery had a normal appendix; 7 patients did not have CT, 5 patients had surgery despite a negative CT, and 3 patients had a false-positive CT. Negative appendectomy rates were lowered overall (20% to 7%), in men (11% to 5%), in women (35% to 11%), in boys (10% to 5%), and in girls (18% to 12%). Appendiceal perforation rates dropped from 22% to 14% after CT availability. CT excluded appendicitis in 206 patients in 1997 who avoided appendectomy and identified alternative diagnoses in 105 of these patients (51%). CONCLUSION: The availability of appendiceal CT coincided with a drop in the negative appendectomy rate from 20% to 7% in all patients, and to only 3% in patients with a positive CT. Perforation rates decreased from 22% to 14%. Appendiceal CT can be advocated in nearly all female and many male patients. (+info)
Comparison of standard and CA-125 response criteria in patients with epithelial ovarian cancer treated with platinum or paclitaxel.
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PURPOSE: To assess CA-125 as a measure of response in patients treated with paclitaxel. PATIENTS AND METHODS: One hundred forty-four patients treated with paclitaxel derived from four different trials and 625 patients treated with platinum from two trials were analyzed using precisely defined 50% and 75% reductions in CA-125. The standard and CA-125 response rates to paclitaxel and platinum were compared. In addition, we analyzed individual patient groups in which there was a difference in response according to the two response criteria. RESULTS: Patients with stable disease as determined by standard criteria who were treated with platinum and responded according to CA-125 criteria have an improved median progression-free survival compared with patients with stable disease who did not respond according to CA-125 criteria (10.6 v 4.8 months; P<.001). Standard and CA-125 response rates for patients treated with platinum (58.93% v 61.31%, respectively) and paclitaxel (30.65% v 31.67%, respectively) were very similar, as were rates of false-positive prediction of response by CA-125 (platinum 2.2% and paclitaxel 2.9%). Responders to paclitaxel had a significantly improved progression-free survival compared with non-responders by both standard criteria (median progression-free survival, 6.8 v 2.5 months; P<.001) and CA-125 criteria (median progression-free survival, 6.8 v 3.4 months; P<.001). CONCLUSION: Forassessing activity of therapy for ovarian cancer, these data show that precise 50% or 75% CA-125 response criteria are as sensitive as standard response criteria. We propose that they may be used as a measure of response in lieu of or in addition to standard response criteria in clinical trials involving epithelial ovarian cancer. Sensitivity is maintained whether patients are treated with platinum or paclitaxel. (+info)