A comparison of the effects on the Shwartzman phenomenon of leukopenia produced by nitrogen mustard and by whole body irradiation

The effect of leukopenia on the susceptibility of rabbits to the localized Shwartzman reaction was studied in those receiving whole body irradiation and nitrogen mustard respectively. Of animals receiving nitrogen mustard in which the total polymorphonuclear leukocyte count was less than 100 cells/c.mm. only 17 per cent developed positive local Shwartzman reactions whereas 75 per cent of irradiated animals with total polymorphonuclear leukocyte counts less than 100 cells/c.mm. had positive reactions. A local Shwartzman reaction occurred in 60 of 71 control rabbits (85 per cent). Animals of both the treated groups showed positive Shwartzman reactions at a time when their total polymorphonuclear leukocyte counts were less than 500 cells/c.mm. From the findings, it is concluded (a) that the presence of normal numbers of circulating polymorphonuclear leukocytes is not an obligatory prerequisite condition to the localized hemorrhagic necrosis of the Shwartzman phenomenon, and (b) the mechanisms of action of nitrogen mustard and whole body irradiation on body tissues differ in relation to the Shwartzman reaction.

The distribution of blood cells on haemacytometer counting chambers with special reference to the amended British Standards Specification 748 (1958)

The distribution of leucocytes and erythrocytes on the haemacytometer counting chamber is shown. Differences between total leucocyte counts on single and double-ruled chambers are given and the effect of different lengths of cover glass are discussed. An assessment of the relative accuracy of the amended British Standards Specification (B.S.S.) 748 (1958) double-ruled bright line chamber and the old B.S.S. chambers in made.

Observations on the use of the Coulter model D electronic cell counter in clinical haematology

The use of the Coulter electronic cell counting machine (model D) in a routine pathological laboratory is described, as are also the technical details involved.

STUDIES ON THE LYMPHOCYTOSIS INDUCED IN MICE BY BORDETELLA PERTUSSIS

1. Intravenous injection into mice of phase I Bordetella pertussis vaccine resulted in a striking hyperleucocytosis with a predominating lymphocytosis. Intraperitoneal inoculation was less effective, and subcutaneous administration was inactive. 2. Active immunization prevented the hyperleucocytosis; passive immunization was less effective. 3. Reticuloendothelial blockage reduced the effect of the vaccine. 4. Extirpation of the spleen or thymus did not alter the leucocyte response. 5. Histologic studies suggested that the increase in circulating lymphocytes resulted from release of cells from lymphoid organs, including the thymus.

AN EVALUATION OF THE VICKERS INSTRUMENTS J12 CELL COUNTER

The Vickers J12 cell counter uses an optical hydraulic counting system to perform rapid automatic counts of leucocytes and erythrocytes in liquid suspension. The effect of sample storage, the use of different diluents, variation in cell dimensions and other relevant factors have been studied. A counting accuracy of +/- 1.19% for replicate erythrocyte counts and +/- 2.94% for leucocyte counts was obtained.

THE ROLE OF INTESTINAL BACTERIA IN THE RECOVERY FROM WHOLE BODY RADIATION

Non-absorbable antibiotics, neomycin sulfate or polymyxin B, prevent death from an otherwise lethal dose of whole body radiation by suppressing the activity of the Gram-negative bacterial flora of the intestinal tract. The protective effect of such suppression has been evaluated over a range of radiation exposure from 325 to 675 r. Coliform-free animals uniformly survive exposure to 550 r, a dose which is regularly lethal for coliform bearing animals. When antibiotic treatment is begun within 1 hour after 550 r whole body radiation, survival is the rule. Delay in starting treatment is critical, for the longer the delay, the higher the mortality, even though the stool cultures meanwhile become coliform-free. When antibiotic is started prior to or immediately after radiation exposure, it must be continued for at least 3 weeks if maximum effectiveness is to be obtained. The shorter the postradiation period of treatment, the greater the mortality. This suggests that the defense systems involved require protection for at least 3 weeks in order to permit return of maximal function. The non-absorbable intestinal antibiotics are effective only when cultural data demonstrate successful elimination of the coliform flora in the gut.