Learned helplessness in Drosophila melanogaster?
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Animals↗
Biomedical subjects
C L Robertson
Publications and source records attributed to C L Robertson.
A private breast imaging practice: medical audit of 25,788 screening and 1,077 diagnostic examinations.
During 1989 and 1990, 25,788 screening and 1,077 diagnostic breast imaging examinations were performed. Audit was performed in 6-month intervals to allow comparison of performance over time. Sensitivity, positive predictive value, and stage of disease were determined for each radiologist, for patients over and those under 50 years of age, and for patients with and for those without a suspect palpable breast abnormality. In the screening portion of the study, 1,539 of 25,788 (5.9%) patients were asked to return for diagnostic breast imaging, 119 of 188 (63%) cancers were stage 0 or stage 1 disease, and a sensitivity of 91% and a positive predictive value of 11% were found. If patients with a palpable breast abnormality were eliminated, 103 of 138 (75%) patients had disease that was less than stage 2. In the diagnostic portion of the study, 296 of 1,077 (27%) patients were referred for biopsy and 53 of 71 (75%) cancers were stage 0 or stage 1 disease. A sensitivity of 97% and a positive predictive value of 24% were found. If patients with a palpable breast abnormality were eliminated, 51 of 63 (81%) patients had disease that was less than stage 2.
Breast Neoplasms↗
Communication problems after mammographic screening.
The authors prospectively assessed the effectiveness of requests for immediate additional evaluation or biopsy made on the basis of the interpretation of abnormal findings on screening mammograms. In 1,125 screening mammograms obtained in asymptomatic women referred by physicians, the findings in 63 (6%) were interpreted as requiring additional imaging or biopsy. Written reports were sent, and in all cases the office of the referring physician was notified directly by phone. Physicians were periodically contacted if no follow-up had been performed to resolve the questioned abnormality. In the first 2.5 months, no action had been taken in 40 of 63 (63%) of the recommendations. After additional calls, this diminished to 10 of 63 (16%) at 3.5 months, but at 4.5 months four of 63 (6%) patients had not undergone the recommended additional studies. These results suggest the need for development of systems to ensure prompt action in patients with abnormal findings at mammographic screening.
Communication↗
Improved control of image optical density with low-dose digital and conventional radiography in bedside imaging.
The technical and diagnostic performance of simultaneously acquired low-dose (44% of standard dose) storage-phosphor digital radiographs (system resolution = 0.2 mm, 10 bits) were compared with those of standard-dose conventional bedside radiographs of the chest in 32 patients. The mean optical density (OD) of the lungs (800 measurements) was closer to the ideal density with digital radiography (1.45 OD +/- 0.20 [standard deviation] vs 1.75 OD +/- 0.53) and was less often outside the usable range (2.5% vs 42.5%). Receiver operating characteristic analysis for detection of simulated nodules and monitoring devices (nine readers, 4,608 observations) showed that digital radiography was superior to conventional radiography (P less than .05) for four of the nine readers and equivalent to conventional radiography for five readers. The authors concluded that digital radiography produces more consistent and ideal image density and performs at least as well as conventional radiography under phantom test conditions.
Absorptiometry, Photon↗
Nonpalpable lesions in the augmented breast: preoperative localization.
Special compression views of the breast were used to detect suspect lesions in eight women who had undergone augmentation mammoplasty. Hook-wire localization with the use of these views proved safe and accurate for preoperative localization in these women, one of whom had a very small cancer.
Breast↗
Why isn't every woman over 40 in a breast cancer detection program?
Mortality from breast cancer may be reduced by more than 10,000 deaths per year in this country if the recommendations for screening all asymptomatic women older than 40 years for breast cancer, issued in 1982 by the American Cancer Society and the American College of Radiology, are followed. Compliance with those recommendations six years later is poor, even in well-to-do, medically served populations, primarily because of poor compliance by physicians. Radiation risk is an often-cited concern, although it has been shown to be an insignificant factor in breast cancer screening. High cost, also cited as a concern, is less of a problem-the charges for mammography having declined steeply in the past few years. At the current price levels, it makes financial and humanitarian sense to provide screening rather than terminal care for metastatic breast cancer. The third concern cited by physicians, that of diagnostic accuracy, must be addressed by a careful and accurate statistical description of the results of each screening program. Sensitivity of more than 80% with positive predictive values of about a third can be achieved.
Adult↗
Factors relating to the sensory acuity of limbs with peripheral vascular insufficiency.
We examined several possible causes for the high incidence of poor sensory acuity in the limbs of 176 patients with moderate to severe peripheral vascular insufficiency. We investigated the relationships of diabetes, alcoholism, and smoking, as well as the severity of peripheral vascular disease, to the integrity of basic sensory modalities such as two-point discrimination and perception of light touch. The presence or absence of diabetes exerted the strongest effect on peripheral sensation. In patients who did not have diabetes, sensation in the limbs was most strongly affected by whether the patient was an alcoholic. Smoking did not have a significant effect on limb sensation. Among nondiabetic, nonalcoholic patients, there was a weak residual effect related to the severity of the peripheral vascular insufficiency. Even among these patients, however, systemic factors predominated in determining the loss of sensation. We also examined the extent to which loss of sensation might be related to the development of ulcers. Among patients who were not diabetic, there was a highly significant relationship between loss of sensation and the presence of limb ulceration. Surprisingly, however, there was no discernable relationship between the presence of ulcers in diabetic patients and the degree of loss of peripheral sensation. This result suggests that a large percentage of ulcers seen in diabetic patients are not of neurogenic origin.
Adult↗
Water-soluble radiocontrast material in the treatment of postoperative ileus.
Reviewed was a series of 47 obstetric, gynecologic, and general surgical patients with apparent postoperative ileus who had received an oral administration of water-soluble radiocontrast material. Forty of these patients were found to have an ileus, and seven to have a mechanical small bowel obstruction. In the 40 patients with ileus, prompt resolution of the ileus was obtained, no complications were noted, and the method provided rapid differentiation between ileus and obstruction. This modality of therapy offers an excellent alternative both therapeutically and diagnostically to the traditional treatment of ileus with intravenous fluid, nasogastric suction, and gastrointestinal rest.
Administration, Oral↗
The relationship of transcutaneous PO2 and laser Doppler measurements in a human model of local arterial insufficiency.
Transcutaneous PO2 and laser Doppler measurements were made over areas of unheated and heated skin of the feet of normal volunteers. Stepwise elevation of the foot above the level of the heart systematically reduced the local arterial pressure and, thus, the local arteriovenous gradient in these areas. Results indicated that transcutaneous PO2 and laser Doppler measurements reflect changes in local arteriovenous gradient when made over areas of warmed skin, but not unwarmed skin. Comparison of skin surface and subcutaneous temperatures obtained with two heater types revealed the importance of heater configuration. Results confirm a previously hypothesized nonlinear relationship between transcutaneous PO2 and local cutaneous blood flow and indicate that a transcutaneous PO2 reading of zero may be obtained in the presence of significant local cutaneous blood flow.
Arterial Occlusive Diseases↗
The effect of exercise upon cutaneous oxygen delivery in the extremities of patients with claudication and in a human laboratory model of claudication.
Transcutaneous PO2 measurements have been shown previously to reflect local cutaneous oxygen delivery in patients with severe peripheral arterial insufficiency. In the present studies, transcutaneous PO2 measurements indicated that exercise of the involved extremity lowered cutaneous oxygen delivery in patients with moderate peripheral arterial insufficiency (claudication). These exercise-related changes in transcutaneous PO2 were reproduced in a human laboratory model of claudication. The pattern of change in transcutaneous PO2 observed in this model during and after exercise correlated closely with the pattern of change in mean systemic blood pressure during the same time period.
Ankle↗
The use of a Foley catheter for removal of blunt esophageal foreign bodies from children.
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Catheterization↗