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Biomedical subjects

W C Phillips

Publications and source records attributed to W C Phillips.

31 records · Page 2Linked to original sources
PubMed1983

Fracture of the radius with instability of the wrist.

Review of 190 consecutive fractures of the distal radius revealed 14 instances of ligamentous carpal instability (7.4%). Instability was more likely to occur in older patients but was not related to the degree of fracture displacement. There was an association between instability and radial styloid fracture, and in five of nine Colles fractures a separate radial styloid fragment was present, suggesting a component of avulsive force. The relatively common coexistence of fracture and instability is not generally appreciated, and the findings of instability often are overlooked.

Humans↗
PubMed1983

Statistics for diagnostic procedures. II. The significance of "no significance": what a negative statistical test really means.

Statistical tests are often used to compare two or more groups. When the tests show "no significant difference," many authors/readers conclude that this means that the groups are identical. Often this outcome is merely the result of inadequate sample size. The adequacy of sample size depends on well established mathematical principles, not on the investigator's intuition. The real meaning of "no significant difference" is discussed.

Diagnosis↗
PubMed1983

Statistics for diagnostic procedures. III. Philosophic and research design considerations.

Statistical analysis of data presupposes that properly designed research has been performed. Improperly performed studies are worse than none at all because they cause readers to assume erroneously that useful information has been obtained when it has not. Important points include thorough pretrial planning without mid-course alterations, clear identification/definition of relevant parameters, correct interpretation of data, and willingness to publish negative results.

Diagnosis↗
PubMed1983

Efficacy of preoperative hip aspiration performed in the radiology department.

The results of 148 preoperative hip aspirations performed in the radiology department were analyzed and compared with those of preoperative aspirations done in the operating room in another group of patients. The aspirations were performed in a standard fluoroscopic room used only for "clean procedures"; strict aseptic precautions were used. The majority of patients had undergone prosthetic hip arthroplasty. The results were comparable, i.e., the sensitivity for the radiologic aspirations was 0.88, as compared with 1.00 for intraoperative aspirations; the specificities were 0.83 and 0.78, respectively. The advantages of aspirations done in the radiology department include lower cost, shorter hospitalization, and simultaneous performance of arthrography, if indicated. Important aspects of technique include meticulous aseptic precautions, avoidance of local anesthetics, and prompt transportation of the specimen to the laboratory.

Adolescent↗
PubMed1982

Primary lymphoma of bone: relationship of radiographic appearance and prognosis.

A retrospective review was made of the pretreatment radiographs of 20 patients with well-documented primary lymphoma of bone. Nine radiographic signs were defined, and the presence or absence of each was recorded for each patient. When the radiographic findings were compared with disease-free survival for each patient, it was found that patients who had a relapse had a higher mean number of positive radiographic signs than those who remained disease free (p less than 0.02). Also, those who relapsed early had more positive signs than those who relapsed late (p less than 0.05). Certain signs, i.e., pathologic fracture, layered periosteal new bone, broken periosteal new bone, cortical breakthrough, soft-tissue mass, and soft-tissue swelling, were more helpful than others for making a prognosis. These signs appear to be related to radiologic evidence of imminent or actual soft-tissue extension of the tumor.

Adult↗
PubMed1982

Prosthetic hip replacements: plain films and arthrography for component loosening.

Component loosening of prosthetic hip replacements was evaluated solely by plain films in 56 patients and solely by arthrography in 49. Radiographic results and surgical findings were compared in all cases. Arthrography was associated with fewer errors. For acetabular component loosening, there were 11% fewer errors made by arthrography (26% versus 15%). However, for femoral component loosening, the number of errors decreased by only 3% (15% versus 12%). The errors associated with evaluation of the acetabular component were predominately false-positive, both on plain films and arthrography. For femoral component evaluation, plain films and arthrography were predominately associated with false-negative errors.

Adolescent↗
PubMed1982

Paget's disease of bone mimicking metastases.

Seven patients with Paget's disease, mimicking the radiographic appearance of metastatic disease, are illustrated. This disorder may simulate metastases if the simultaneous processes of bone resorption and new bone formation are not apparent, especially if there is no evidence of bone enlargement. Additional confusion may arise if the lesion is monostotic, has an unusual location, or occurs in a patient with known or suspected malignant disease.

Adult↗
PubMed1979

Polyoma virion and capsid crystal structures.

X-ray diffraction shows that complete virus particles and empty capsids crystallize isomorphously. The surface morphology of the protein coat, as revealed by electron microscopy, is the dominant structural feature determining the intensity of x-ray reflections to a resolution of approximately 30 angstroms. The structure and variability of the viral chromatin core can now be analyzed by comparison of electron density maps.

Crystallization↗
PubMed1977

Gap junction structures. I. Correlated electron microscopy and x-ray diffraction.

X-ray crystallographic methods and electron microscope image analysis have been used to correlate the structure and the chemical composition of gap junction plaques isolated intact from mouse liver. The requirement that the interpretations of X-ray, electron microscope, and chemical measurements be consistent reduces the uncertainties inherent in the separate observations and leads to a unified picture of the gap junction structures. Gap junctions are built up of units called connexons that are hexagonally arrayed in the pair of connected cell membranes. X-ray diffraction and electron microscope measurements show that the lattice constant of this array varies from about 80 to 90 A. Analysis of electron micrographs of negatively stained gap junctions shows that there is significant short range disorder in the junction lattice. even though the long range order of the array is remarkably regular. Analysis of the disorder provides information about the nature of the intermolecular forces that hold the array together.

Animals↗
PubMed1977

Gap junction structures. II. Analysis of the x-ray diffraction data.

Models for the spatial distribution of protein, lipid and water in gap junction structures have been constructed from the results of the analysis of X-ray diffraction data described here and the electron microscope and chemical data presented in the preceding paper (Caspar, D. L. D., D. A. Goodenough, L. Makowski, and W.C. Phillips. 1977. 74:605-628). The continuous intensity distribution on the meridian of the X-ray diffraction pattern was measured, and corrected for the effects of the partially ordered stacking and partial orientation of the junctions in the X-ray specimens. The electron density distribution in the direction perpendicular to the plane of the junction was calculated from the meridional intensity data. Determination of the interference function for the stacking of the junctions improved the accuracy of the electron density profile. The pair-correlation function, which provides information about the packing of junctions in the specimen, was calculated from the interference function. The intensities of the hexagonal lattice reflections on the equator of the X-ray pattern were used in coordination with the electron microscope data to calculate to the two-dimensional electron density projection onto the plane of the membrane. Differences in the structure of the connexons as seen in the meridional profile and equatorial projections were shown to be correlated to changes in lattice constant. The parts of the junction structure which are variable have been distinguished from the invariant parts by comparison of the X-ray data from different specimens. The combination of these results with electron microscope and chemical data provides low resolution three- dimensional representations of the structures of gap junctions.

Animals↗