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Biomedical subjects

J Bishop

Publications and source records attributed to J Bishop.

At least 163 records · Page 9Linked to original sources
PubMed1966

The Canadian drug adverse reaction reporting program.

The origins and objectives of the Food and Drug Directorate's Drug Adverse Reaction Reporting Program are reviewed. A brief report from (F&D 123), which has been made available to all physicians, provides the means whereby suspected reactions to drugs can be reported to the Directorate. Information contained in these reports is treated as confidential. Twelve Canadian teaching hospitals have entered into a contractual agreement with the Directorate in order to investigate and evaluate suspected drug reactions occurring in the hospital setting. Manufacturers are notified if a problem appears to be arising in connection with a product, and discussions are held before any regulatory action is taken. Also, under the New Drug Regulations of 1963, pharmaceutical manufacturers are required to notify the F.D.D. if any unexpected reactions occur in association with their products. The Food and Drug Directorate is giving considerable thought to the means by which the interest of the profession in this program may be stimulated.

Canada↗
PubMedDate not supplied

Dynamic spin-echo imaging: theoretical assessment and implementation.

A spin-echo method for obtaining dynamic magnetic resonance (MR) images is described. The method combines the RARE (rapid acquisition with relaxation enhancement) pulse sequence with a data acquisition scheme in which only a centric fraction of the raw data is sampled to increase the time resolution of the dynamic images. The missing high-resolution data are supplied from reference images. By these means, an effective time resolution of about 10 seconds per image is achieved, which is suitable for diagnostic assessment of contrast enhancement procedures. A promising clinical application is contrast-enhanced MR imaging of the pituitary. Although the resolution of small objects in this size range is potentially degraded, this shortcoming is compensated for with use of variable refocusing flip angles. In the context of pituitary imaging, the centric 30%-40% of the raw data is shown to be the optimal fraction to acquire for the low-resolution dynamic images. Ten patients with previous history of pituitary disease have been imaged with dynamic and conventional spin-echo techniques. In six of these patients, an equivalent diagnosis was reached with dynamic and conventional images, while in two, only the dynamic images showed the lesion; in the final two patients, only the conventional images showed the lesion.

Adenoma↗
PubMedDate not supplied

Errors in quantitative dynamic three-dimensional keyhole MR imaging of the breast.

Three-dimensional (3D) keyhole magnetic resonance (MR) imaging has been proposed as a means of providing dynamic monitoring of contrast agent uptake by breast lesions, with complete breast coverage and high spatial and temporal resolution. The 3D keyhole technique dynamically samples the central regions of k-space in both phase-encoding directions and provides high-frequency data from a precontrast acquisition. Errors due to data truncation with two-dimensional and 3D region-of-interest measurements are estimated from a numerical simulation of various implementations of the 3D keyhole technique. Errors were found to increase with increasing temporal resolution and reduced object size. Errors of 75% are possible for objects with a diameter approaching 1 pixel when a 3D keyhole implementation that samples 50% of phase-encoding data in each direction is used. Preliminary clinical images with this approach illustrate artifacts consistent with inadequate k-space sampling.

Artifacts↗
PubMedDate not supplied

Magnetic resonance imaging of shear wave propagation in excised tissue.

The propagation of shear waves in ex vivo tissue samples, agar/gel phantoms, and human volunteers was investigated. A moving coil apparatus was constructed to generate low acoustic frequency shear perturbations of 50 to 400 Hz. Oscillating gradients phase-locked with the shear stimulus were used to generate a series of phase contrast images of the shear waves at different time-points throughout the wave cycle. Quantitative measurements of wave velocity and attenuation were obtained to evaluate the effects of temperature, frequency, and tissue anisotropy. Results of these experiments demonstrate significant variation in shear wave behavior with tissue type, whereas frequency and anisotropic behavior was mixed. Temperature-dependent behavior related mainly to the presence of fat. Propagation velocities ranged from 1 to 5 m/sec, and attenuation coefficients of from 1 to 3 nepers/unit wavelength, depending on tissue type. These results confirm the potential of elastic imaging attributable to the intrinsic variability of elastic properties observed in normal tissue, although some difficulty may be experienced in clinical implementation because of viscous attenuation in fat.

Adipose Tissue↗
PubMedDate not supplied

Presence and distribution of immunoreactive and bioactive FMRFamide-like peptides in the nervous system of the horseshoe crab, Limulus polyphemus.

FMRFamide immunoreactivity was detected in all regions of the Limulus nervous system, including the brain (6.5 +/- 0.6 pg FMRFamide/mg), cardiac ganglion (2.06 +/- 0.67 pg FMRFamide/mg), and ventral nerve cord (5.8 +/- 0.7 pg FMRFamide/mg). The distribution of immunoreactive FMRFamide (irFMRFamide) was mapped by immunofluorescence and the distribution corresponded to regional RIA data. A good proportion of the CNS and cardiac ganglion neuropile contained irFMRFamide, and fluorescent cell bodies were observed in several areas. High performance liquid chromatography (HPLC) was employed to separate and characterize the FMRFamide-like peptides from extracts of Limulus brains. HPLC fractions were analyzed using coincidental radioimmunoassay and bioassay (the radula protractor muscle of Busycon contrarium). There appear to be at least three FMRFamide-like peptides in the Limulus brain, including one similar to clam FMRFamide. FMRFamide acts on Limulus heart in a biphasic manner at relatively high concentrations (10(-5)M), but has no effect on the activity of the isolated ventral nerve cord. These data suggest that in Limulus FMRFamide-like peptides are acting as neurotransmitters, or neuromodulators.

Animals↗
PubMedDate not supplied

Detection of HLA antibodies by platelet crossmatching techniques.

Thirty-seven monospecific HLA antibodies directed against all common HLA-A and -B loci and reactive by the microlymphocytotoxicity assay (LCT) were tested against platelets carrying the corresponding antigen by three platelet crossmatch methods, the platelet immunofluorescence test (PIFT), platelet enzyme-linked immunosorbent assay (P-ELISA), and platelet radioimmunoassay (P-RIA). Positive reactions were obtained with the PIFT in 67 percent, the P-ELISA in 41 percent, and the P-RIA in 49 percent of 85 cell-serum pairs. The same cell-serum combinations gave 49 percent positive reactions in the lymphocyte immunofluorescence test. Three multispecific HLA antisera were positive in nine of nine cell-serum combinations by all four methods. Thirteen transfusions were given to eight patients with known HLA antibodies. All donor-recipient pairs were LCT positive, six were PIFT positive, and seven were PIFT negative. Three of seven PIFT-negative and none of six PIFT-positive transfusions were successful. Thus, platelet crossmatching is less sensitive than the LCT for the detection of complement-binding monospecific HLA antibodies. The platelet crossmatch, however, is able to identify some potentially successful HLA-incompatible donors for patients with multispecific HLA antibodies and limited access to HLA-identical donors.

Antibodies↗
PubMedDate not supplied

Accuracy of thin-layer cytology in patients undergoing cervical cone biopsy.

OBJECTIVE: To compare the accuracy of thin-layer cytology with Autocyte PREP (TriPath Imaging Inc., Burlington, North Carolina, U.S.A.) with conventional smears in 500 women undergoing cervical cone biopsy. STUDY DESIGN: The study was performed among 500 consecutive women presenting for cone biopsy for high grade cervical intraepithelial neoplasia (CIN) on biopsy in 350 (70%) and discrepant cytology/colpohistology in 150 (30%). Before performing a cone biopsy, two cervical samples were collected for conventional smears and thin-layer cytologic slides, with randomization of the order. Conventional smears were stained and diagnosed at Pasteur Cerba, while thin-layer cytologic slides were processed at a local TriPath office (Meylan, France) and sent in a masked fashion for screening at Pasteur Cerba. Any slides initially read as normal were reviewed again and reported without knowledge of the other cytologic or cone biopsy data. The final cytologic diagnoses for the two methods were compared with histopathology of the cone biopsy. RESULTS: The conventional smear was unsatisfactory in 58 (11.6%) of cases, while there were 4 (0.8%) unsatisfactory thin-layer cytologic slides (P < .001). Endocervical cells were missing from 31 (6.2%) of conventional smears and 34 (6.8%) of thin-layer cytologic slides. For the pooled data, sensitivities of conventional smear and thin layer for detecting high grade CIN (0.82% and 0.86%, respectively) were similar as were specificities (0.40% and 0.43%, respectively). When first samples were compared, the sensitivities of the conventional smear and thin layer for high grade CIN were 0.79% and 0.89%, respectively (P = .02), with corresponding specificities of 0.41% and 0.36% (P < .01). CONCLUSION: When controlled for sample order, the sensitivity of thin-layer cytology for detecting high grade CIN was significantly higher than that of conventional smears in patients with previous abnormal cytology, but at the expense of specificity.

Biopsy↗
PubMedDate not supplied

Radical manager.

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Humans↗
PubMedDate not supplied

Model-making.

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Child, Preschool↗