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Biomedical subjects

P H Carter

Publications and source records attributed to P H Carter.

14 recordsLinked to original sources

Flow cytometric analysis of whole blood lysis, three anticoagulants, and five cell preparations.

We studied the effects of anticoagulants and cell preparation methods on lymphocyte forward-angle scatter (FSC), autofluorescence, and immunofluorescent staining for CD45, CD14, and CD13. Blood samples collected in ethylenediaminetetracetic acid (EDTA), heparin, and acid citrate dextrose (ACD) were processed by using conventional Hypaque-Ficoll (HF) separation and four whole blood (WB) lysis techniques: Immuno-lyse, Q-Prep, FACS Lyse, and Gen Trak Lysis. Lymphocytes prepared by using three of the four whole blood methods gave FCS values comparable to those isolated by HF, while one method (FACS Lyse) gave consistently lower values. Autofluorescence values were comparable by all methods except Immuno-lyse, which showed consistently higher values in blood stored for 24 h with any anticoagulant. Immunofluorescent values for CD45-stained cells were quite consistent across all methods, and among the whole blood methods, FACS Lyse and Q-Prep uniformly gave the highest purity of CD45-positive cells in the lymphocyte light scatter gates. Additionally, propidium iodide (PI) analyses of CD45-stained whole blood, and analyzed without lysis, confirmed that ACD and heparin were superior to EDTA for maintaining viable leucocytes overnight. Future studies should focus on other commonly used reagents, a wide variety of abnormal samples, and cell viability.

Antigens, CD

Comparison of type 2 and type 6 fimbriae of Bordetella pertussis by using agglutinating monoclonal antibodies.

Two types of fimbriae have been identified on the pathogenic gram-negative organism Bordetella pertussis. Monoclonal antibodies to these fimbriae were produced to better understand the role of fimbriae as serotype-specific agglutinogens and to investigate the antigenic relationship between these fimbriae. Three monoclonal antibodies were identified that specifically agglutinated B. pertussis cells containing the U.S. Reference Factor 2 agglutinogen, and six monoclonal antibodies were produced that agglutinated only those strains containing the U.S. Reference Factor 6 agglutinogen. Indirect immunofluorescence studies and immunogold electron microscopy demonstrated that these monoclonal antibodies bind to an outer membrane component on serotype-specific strains of B. pertussis. All of the monoclonal antibodies reacted with native or partially assembled type-specific fimbriae but not with monomeric fimbrial subunits as indicated by Western blot (immunoblot) analysis. The fimbrial agglutinogens recognized by the monoclonal antibodies were also uniquely reactive with either U.S. Reference Factor 2 or 6 antiserum (Eldering agglutinogen 2 or 6 polyclonal antiserum) in an indirect ELISA. No cross-reactivity of the monoclonal antibodies with the unrelated fimbriae was observed in any of the comparative immunological studies. Some of the monoclonal antibodies agglutinated certain strains of B. bronchiseptica, suggesting that this closely related species can contain antigenically similar fimbriae. These monoclonal antibodies should prove useful for further structural and functional analysis of Bordetella fimbriae and for studies on the role that these antigens play in prevention of infection and disease.

Agglutination Tests

Purification and characterization of fimbriae isolated from Bordetella pertussis.

Fimbriae were detached from Bordetella pertussis by mechanical shearing and purified by successive precipitations with ammonium sulfate, phosphate buffer (pH 6.0), and magnesium chloride. In each of these purification steps, the fimbriae aggregated into bundles as seen by electron microscopy. These aggregates could be disaggregated at pH 9.5. By electron microscopy, the purified fimbriae appeared as long filaments with a diameter of 5 nm. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified fimbriae showed a single protein subunit with a molecular weight of 22,000. The purified fimbriae did not have hemagglutinating activity when assayed with several types of erythrocytes, and they were antigenically, chemically, and structurally distinct from the filamentous hemagglutinin of B. pertussis. The purified fimbriae were also identified as serotype 2 agglutinogens, since antibody to the purified fimbriae agglutinated B. pertussis strains serotyped as 1.2.4, 1.2.3, or 1.2.3.6 but did not agglutinate those serotyped as 1.3.6.

Agglutination

The ability of some Yersinia enterocolitica strains to invade HeLa cells.

Many types of Yersinia enterocolitica have been isolated from animal, environmental, food, and human sources but their public health significance remains uncertain. Seventy two strains of Y. enterocolitica were tested for their abilities to invade HeLa cells. The typical clinical strains invade HeLa cells like the other species of invasive pathogens. This characteristic remains even in old stock cultures and can be temperature-sensitive like the motility characteristic. With the use of electron micrographs it was demonstrated that the bacteria were truly intracellular and not merely adhering to the HeLa cell membrane. The esculin-and salicin-positive typical clinical strains did not invade HeLa cells. None of 34 food and water isolates were invasive by this test. The negative Y. enterocolitica strains did not adhere to the cells and cause ambiguous results. The HeLa cell test is simple, inexpensive, rapid, and should prove useful marker for screening the Y. enterocolitica isolates.

Adhesiveness

Spironolactone and acute mountain sickness.

Thirteen adults trekking in Nepal in 1974 to altitudes between 4,300 m and 5,500 m remained free from acute mountain sickness while taking spironolactone as a prophylactic measure. Two years previously five of these adults trekking at similar altitudes, but without treatment, had suffered from acute mountain sickness. The regime used was spironolactone in a dosage of 25 mg three times a day for two days preceding and during the periods spent at altitudes above 3,000 m.

Acute Disease

The integrated syllabus.

A detailed programme of DCR Course objectives subsectioned and examined according to a student radiographer's learning progress, rather than strict, subject matter boundaries. Taking the above definition as its model, this paper describes and discusses historical, educational and practical views of the qualifying Diploma of the College of Radiographers and outlines proposals, based on a questionnaire survey, for its restructuring.

Curriculum