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Biomedical subjects

J L Sloyer

Publications and source records attributed to J L Sloyer.

6 recordsLinked to original sources
PubMed1990

The electrophoretic mobility of gram-negative and gram-positive bacteria: an electrokinetic analysis.

The electrophoretic mobility (EPM) of a variety of Gram-negative and Gram-positive bacteria was measured with a Penkem S3000 analyser. Under standard growth conditions and neutral pH all cells displayed a negative EPM. The polysaccharide capsules of Escherichia coli strains K1, K5, K29 and K30 generated the highest EPM; to a lesser and varying degree O-antigens with charged groups and core lipopolysaccharides also contribute to the net EPM. Very little negative EPM was measured in suspension cultures of the gliding bacterium Cytophaga U67. No difference in the EPM was observed between rapidly growing and stationary-phase E. coli B. De-energization of the cell membranes by carbonyl cyanide m-chlorophenylhydrazone (CCCP) did not affect the EPM of wild-type and deep rough mutants of E. coli; and the EPM of Cytophaga U67 and Acholeplasma laidlawii remained unaltered by CCCP when measured in their respective growth media. Extrusion of filamentous bacteriophage f1 from cells of its host, E. coli A95, caused a shift to a higher negative EPM. We also measured a variety of Gram-positive strains, all of which displayed different EPMs. When membrane fractions of E. coli were adsorbed to latex spheres, characteristic differences between the EPM of beads coated with either inner or outer membrane were observed. The results suggest that the rapid EPM analysis is a useful tool to study the net electric charge of microorganisms and to examine changes of surface properties during interaction of cells with viruses, proteins (antibody) and charged antibiotics.

Anti-Bacterial Agents↗
PubMed1977

Immune response to acute otitis media in children III. Implications of viral antibody in middle ear fluid.

With the technique of radioimmunodiffusion and indirect FA staining, IgA antibody to measles, mumps, rubella, and polio-1 were determined in serum and middle ear fluid (MEF) of 103 patients with otitis media. The occurrence of IgA viral antibody in MEF and its absence in simultaneously drawn serum was used as an indicator of local antibody production. Of the 401 assays performed, 41 instances of IgA antibody exclusively in MEF were found. Only four of these occurred in specimens from unimmunized patients and were directed against rubella virus. Of the 37 remaining cases, 16 each were directed against measles and polio-1 and four and one, respectively, for mumps and rubella viruses. The mean specific IgA titers were from 8- to 17-fold higher in MEF from immunized individuals than in the unimmunized and persisted for at least 9 to 19 months after immunization. The data thus indicate 1) specific immunologic sensitization of the middle ear mucosa can be achieved by parenteral as well as oral routes of immunization, and 2) specific immunologic memory exists in the middle ear mucosa. These two factors are crucial to feasibility of immunization against acute otitis media.

Antibodies, Viral↗
PubMed1975

The immune response to acute otitis media in children. II. Serum and middle ear fluid antibody in otitis media due to Haemophilus influenza.

The antibody response in serum and middle ear fluid was studied in 40 children less than two years of age who had otitis media due to Haemophilus influenzae. Specific antibody in serum was determined by either a bacteriocidal test or an indirect fluorescent antibody test, and in the middle ear fluid by the latter test. For both assays the infecting bacterium of the patient was used. Half of the acute sera and three-fourths of the convalescent sera had antibody of at least one of the IgG, IgM, or IgA classes; IgG occurred most often. Fourteen patients had significant increases in specific antibody in the convalescent serum. Middle ear fluids from 22 to 29 patients had specific antibody. IgG and IgA antibodies occurred with equal frequency, but IgA antibody was found more often in middle ear fluids when IgA antibody was absent from serum. Thus it appears that infants with otitis media respond systemically and locally with specific antibody to H. influenzae.

Acute Disease↗
PubMedDate not supplied

Immunology and microbiology in acute otitis media.

Various immunological parameters were measured in serum, middle ear fluid (MEF), and lymphocytes from peripheral blood and MEF of infants with acute otitis media due to S. pneumoniae or H. influenzae. Approximately half of 131 patients had IgE specific antibody to the infecting bacterium as determined by the indirect fluorescent antibody (IFA) technique. Seventy-one percent of these IgE positive patients had IgE specific antibody in the MEF. Total IgE concentration was found to be from an average of 1.5 to 3.0 times higher in the MEF when compared to the simultaneously drawn serum. In addition, antibody to pneumococcal capsular polysaccharides and to pneumococcal C-carbohydrate was demonstrated in the MEF by radioimmunoassay. When MEF specific antibody was compared to serum antibody it appeared that antibody to C-carbohydrate was more concentrated in the MEF. That this antibody was of the IgE class was suggested by IFA but not conclusively proven. Evidence exists that conditions for enhanced IgE synthesis is concomitantly associated with a decrease in T-cell activity. T-cell function in MEF derived lymphocytes as determined by rosette formation and by phytohemagglutinin (PHA) stimulation was approximately one-tenth that of the peripheral blood lymphocytes. However, that T-cells may participate in the immune response to polysaccharides was suggested by the observation that polysaccharide stimulated peripheral blood lymphocytes from infants immunized with octavalent pneumococcal capsular vaccine underwent protein synthesis two to three times that of the PHA stimulated cells. The clinical significance of this finding as well as the nature of the cell responsible for the increased protein synthesis remains to be established. It is hypothesized that acute otitis media results from local synthesis of bacteria specific IgE antibody which is enhanced by a paucity of local T-cell activity.

Acute Disease↗