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Biomedical subjects

P Sharp

Publications and source records attributed to P Sharp.

107 records · Page 6Linked to original sources
PubMed1976

The measurement of the performance of the display system of radioisotope imaging device: the multi-element band display.

An assessment has been made of the performance of the type of display system in which each display signal intensity, i.e. grey shade or colour, represents a range of count densities or counting rates. In the particular commercially available system used in this investigation eight different grey shades are used to display the image, a range of count densities beingallocated to each grey shade. It is shown experimentally that changes in the distribution of radioisotope can fail to be detected solely due to the manner in which the display is used, viz. The way in which the count density is allocated to the available grey shades. Also, it is shown experimentally that the best display performance can be achieved by using one in which the range of count densities represented by each grey shade is less than three standard deviations of the mean background [corrected] count density.

Background Radiation↗
PubMed1975

Leptospirosis: an underdiagnosed cause of acute febrile illness.

Two cases of leptospirosis diagnosed at the Texas Medical Center in a two-week period are presented. Most cases of leptospirosis go undiagnosed because the symptoms and signs are nonspecific. Leptospirosis should enter the differential diagnosis when symptoms of influenzal illness, aseptic meningitis, and viral gastroenteritis occur, especially if abnormal hepatic and renal function are shown to be present. Many, but by no means all, patients will give history of exposure to livestock or rodents. Diagnosis is best made by serologic methods; Treatment is usually not required since the disease is self-limited, and even in the more severe form, antibiotics have not been conclusively shown to be of benefit.

Acute Disease↗
PubMedDate not supplied

Temporal sequence of viral antigen expression in the cochlea induced by cytomegalovirus.

Injection of guinea-pig cytomegalovirus into seronegative guinea pig cochleas results in viral labyrinthitis. The location of infected cells 1-8 days following inoculation was examined using an immunohistochemical assay for viral antigens. Mesothelial cells below the basilar membrane and those lining the scala tympani, especially below the osseous spiral lamina, were the first cells to express antigen. This occurred 2 days following inoculation. Infection then spread rapidly toward the brain and through the perilymphatic duct to involve inflammatory cells, mesothelial cells of Reissner's membrane, spiral ganglion cells, and the vestibular ganglion cells. In any one cochlea, more mesothelial cells and inflammatory cells expressed viral antigen than any other cell type. It seems then, that there is a differential susceptibility to viral infection and antigen expression in the various cell types of the cochlea. Typical cytomegalic inclusions were common in mesothelial cells. However, many cells labelled for viral antigens did not contain inclusions. The identification of viral antigens then, is a more sensitive technique for demonstrating infection than is the location of cytomegalic inclusion cells.

Animals↗
PubMedDate not supplied

Immunobinding assay for the speciation of avian mycoplasmas adapted for use with a 96-well filtration manifold.

An immunobinding assay capable of distinguishing among Mycoplasma synoviae, M. gallisepticum, M. gallopavonis, and M. meleagridis was developed. A low-protein-binding membrane filter served as the solid support, and a 96-well microsample filtration manifold was used. The assay detected 50 ng of mycoplasmal protein, or approximately 3 x 10(4) colony-forming units, from pure or mixed cultures. No cross-reactions were observed among the mycoplasma species tested. The assay was inexpensive, easy to interpret, and required approximately 3 hr to perform. The 96-well format allowed screening of numerous cultures and use of several antisera in a single assay.

Animals↗
PubMedDate not supplied

Identification of F strain Mycoplasma gallisepticum isolates by detection of an immunoreactive protein.

Commercial laying hens were examined microbiologically at necropsy 31 or 42 weeks after aerosol vaccination with the F strain of Mycoplasma gallisepticum (MG). Mycoplasma isolates were studied in Western blots probed with polyclonal antiserum raised in rabbits to F strain immunogen. The persistence of the vaccine strain was demonstrated by detection of a 75-kilodalton immunoreactive protein, which was present in all MG isolates and thought to be a unique marker of the F strain. Use of PCA-F to probe Western blots allowed simultaneous identification of non-MG isolates, non-F strains of MG, and the F strain of MG.

Aerosols↗
PubMedDate not supplied

Glycoconjugate heterogeneity among five strains of Mycoplasma gallisepticum.

Five strains of Mycoplasma gallisepticum (MG) were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis for the presence of carbohydrate-containing components. Staining with periodic acid-Schiff (PAS) demonstrated carbohydrate components in three of the five strains studied. The PAS-reactive bands counterstained for protein, indicating a possible glycoprotein nature. Western blot analysis using three biotinylated lectin probes demonstrated the presence of additional glycoconjugates in the blot profiles of each MG strain. The carbohydrate specificity of lectin binding was demonstrated by competition experiments using specific sugars. Differences in the number, electrophoretic mobility and the morphology of PAS and lectin reactive bands were reproducible among separate preparations of each MG strain. These findings indicate substantial phenotypic diversity among the five MG strains in their ability to produce or acquire glycoconjugates.

Animals↗
PubMedDate not supplied

Detection of antigenic variation among strains of Mycoplasma gallisepticum by enzyme-linked immunosorbent inhibition assay (ELISIA) and Western blot analysis.

Polyclonal antisera (PCA) to three Mycoplasma gallisepticum (MG) strains (F, S6, and A5969) produced in rabbits were used in enzyme-linked immunosorbent inhibition assay (ELISIA) and Western blot analysis to examine antigenic variability among these strains of MG. In ELISIA, inhibiting antigen of the same strain used for immunization always led to the greatest percentage inhibition of PCA reactivity. Western blot analysis of antigens of four MG strains demonstrated both common and restricted patterns of immune recognition among the three PCAs.

Animals↗