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Biomedical subjects

P E Danielsson

Publications and source records attributed to P E Danielsson.

7 recordsLinked to original sources

Reasons why trauma surgeons fail to screen for alcohol problems.

BACKGROUND: Alcohol screening and intervention have been recommended as routine components of trauma care but are rarely performed. HYPOTHESIS: An association exists between current screening and counseling practices and the trauma surgeon's knowledge, attitude, and perceived role and responsibility toward alcohol problems. PARTICIPANTS: Random-sample survey (n = 241) of members of the American Association for the Surgery of Trauma. MAIN OUTCOME MEASURES: Reported screening and counseling practices. RESULTS: Fifty-four percent of respondents screened 25% or fewer patients, while only 29% screened most patients. The most common reason for not screening was "lack of time." Most (76%) were not familiar with the most common clinically used screening questionnaires, and 83% reported no training in alcohol screening. Screening was more likely if attending physicians perceived a major responsibility for screening (P<.001). Nonscreeners were twice as likely to state screening was "not what I was trained to do" and more frequently believed screening offends patients (P =.001). Independent predictors of screening were perceived major role responsibility (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.38-4.01) and confidence in screening ability (OR, 1.96; 95% CI, 1.05-3.67) and counseling ability (OR, 2.27; 95% CI, 1.34-3.85). Eighty-eight percent of respondents would be willing to devote time to training if shown that counseling is effective. CONCLUSIONS: Lack of screening and counseling appears to be due to cognitive factors, not lack of motivation. Skills on how to screen and counsel for alcohol abuse should be taught to trauma surgeons, because a strong correlation exists between screening and confidence in skills. There is a need for education regarding results of effective intervention trials in medical settings.

Alcohol-Related Disorders↗

Three-dimensional reconstruction from cone-beam data in O(N3 log N) time.

We have used direct Fourier techniques to modify and implement the 3D reconstruction method from cone-beam projections proposed by Grangeat. In this way we manage to decrease the computational complexity from O(N4) to O(N3 log N). Just as Grangeat's original method is exact in the mathematical sense, so is our method, provided a complete set of projection data is acquired. Also in accordance with Grangeat, our algorithm consists of two distinct phases: phase 1, from cone-beam data to derivatives of Radon data; phase 2, from derivatives of Radon data to reconstructed 3D object. In phase 1 we use the direct Fourier method in reverse to obtain line integrals in the detector plane. In phase 2 the 2D linogram method is employed for reconstruction of vertical and horizontal planes in the Radon space.

Algorithms↗

The synthesis of a new x-ray picture identical in projection to a previous picture using 3D Fourier techniques.

A central problem in diagnostic radiology is to compare a new x-ray picture with a previous picture and from this comparison be able to decide whether anatomical changes have occurred in the patient or not. It is of primary interest that these pictures are identical in projection. If not it is difficult to decide with confidence whether differences between the pictures are due to anatomical changes or differences in projection. In this paper we present the geometrical problem and introduce some assumptions that make it possible to find the relative changes in the projection geometry between the exposure of a previous picture and a new picture. The method presented is based on the projection slice theorem (central section theorem). By used 3D Fourier transform techniques we are able to synthesize a new x-ray picture from a set of pictures exposed from a circular orbit above the patient.

Algorithms↗

A comparison of primary cultures of rat cerebral microvascular endothelial cells to rat aortic endothelial cells.

A method to culture rat cerebral microvascular endothelial cells (RCMECs) was developed and adapted to concurrently obtain cultures of rat aortic endothelial cells (RAECs) without subculturing, cloning, or "weeding." The attachment and growth requirements of endothelial cell clusters from isolated brain microvessels were first evaluated. RCMECs required fetal bovine serum to attach efficiently. Attachment and growth also depended on the matrix provided (fibronectin approximately laminin much greater than gelatin greater than poly-D-lysine approximately Matrigel greater than hyaluronic acid approximately plastic) and the presence of endothelial cell growth supplement and heparin in the growth medium. Non-endothelial cells are removed by allowing these cells to attach to a matrix that RCMECs attach to poorly (e.g., poly-D-lysine) and then transferring isolated endothelial cell clusters to fibronectin-coated dishes. These cell cultures, labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethyl-indocarboxyamine perchlorate (DiI-Ac-LDL) and analyzed using flow cytometry, were 97.7 +/- 2.6% (n = 6) pure. By excluding those portions designed to isolate brain microvessels, the method was adapted to obtain RAEC cultures. RAECs do not isolate as clusters and have different morphology in culture, but respond similarly to matrices and growth medium supplements. RCMECs and RAECs have Factor VIII antigen, accumulate DiI-Ac-LDL, contain Weibel-Palade bodies, and have complex junctional structures. The activities of gamma-glutamyl transferase and alkaline phosphatase were measured as a function of time in culture. RCMECs had higher enzymatic activity than RAECs. In both RCMECs and RAECs enzyme activity decreased with time in culture. The function of endothelial cells is specialized depending on its location. This culture method allows comparison of two endothelial cell cultures obtained using very similar culture conditions, and describes their initial characterization. These cultures may provide a model system to study specialized endothelial cell functions and endothelial cell differentiation.

Animals↗

TULIPS: the Uppsala-Linkoping Image Processing System.

The Uppsala-Linkoping Image Processing System, TULIPS, is described. TULIPS, a hardware-software system designed for cell image processing, was developed at Uppsala University Hospital in cooperation with the Department of Electrical Engineering at Linkoping University. The hardware part of the image processing system is built around a high-speed data bus with a capacity of about 40 M byte/sec connected to a PDP-11/55 host computer. An image memory, an LSI-11 microcomputer and a video interface for displaying the image memory content on a TV monitor are also connected to the high-speed bus. An automated microscope and a "Poulsen processor" for low resolution segmentation, both to be attached to the high-speed bus, are being developed. A monitor and an interpreter for an image processing language have been implemented on the host computer. This software system allows interactive, as well as batch, processing. The degree of user interaction is easily adapted to the user's needs. The image processing language is command oriented, and it is easily expanded by adding new commands. The system has been used both for studies in the field of quantitative microscopy and as a platform for development and testing of new image processing algorithms.

Computers↗

Evaluation of methods for shaded surface display of CT volumes.

There are several ways to compute a shaded surface display of radiological 3D density volumes. In this paper we evaluate 12 methods which are different combinations of principles for detection of the surface to be displayed (gray-value threshold, gradient threshold, zero-crossing of 2nd derivative), localizing this surface in space (grid-point accuracy, subvoxel accuracy) and finally estimating the direction of the surface normal (from the gradient in the 2D depth image, from the gradient in the 3D-volume). The best quality is obtained by zero-crossing detection, subvoxel localization, and 3D-gradient orientation.

Data Display↗