Retention of platelets by glass bead filters

Whole blood was passed through glass bead filters and the retention of platelets studied under various experimental conditions. Platelet retention was similar over a wide range of blood flow rates; however, it was decreased at fast rates of flow. Platelet retention was not influenced by the haematocrit value of the blood over a wide range. Retention in filters containing siliconized beads was similar to that in filters with untreated beads. Platelet retention was inhibited by the addition of citrate or adenosine to the blood before passage through the filter and was also less when the blood was cooled. Heparin and phenylindandione therapy did not affect the results.There was a wide range of results of platelet retention tests with normal blood samples and considerable variability between the results of duplicate samples from the same donor. Repeated testing of normal donors over a three-month period gave results which varied widely within the normal range. Twenty-two of 40 uraemic blood samples showed decreased platelet retention. The mechanism of platelet retention from whole blood by glass bead filters is not clear but may be related to platelet aggregation induced by adenosine diphosphate or other aggregating agents.     

Immunity to Influenza in Ferrets: II. Influence of Adjuvants on Immunization

Immunization of ferrets with a single intramuscular inoculation of killed A2/Hong Kong virus did not induce serum or nasal antibody, and these animals were found to be completely susceptible to subsequent infection with virulent influenza virus A2/Hong Kong/3/68. A similar result was found for ferrets immunized with 2 inoculations of killed virus vaccine given 2 weeks apart. Ferrets immunized with killed A2/Hong Kong virus in conjunction with Bordetella pertussis produced relatively low levels of serum HI antibody to A2/Hong Kong virus; when infected with virulent influenza virus, these ferrets showed a modified reaction, with a less marked febrile reaction than was observed for non-immunized animals.Immunization of ferrets with killed A2/Hong Kong virus in Freund''s complete adjuvant resulted in the production of relatively high levels of serum HI antibody, but no detectable nasal antibody. These animals were shown to be partially immune to subsequent infection with virulent influenza virus. However, although the serum antibody levels of these animals following immunization was comparable to that found following infection with live virus, the degree of immunity to infection with virulent influenza virus was measurably less.