Ivan L. Bennett

PSEUDOMONAS BACTEREMIA: REVIEW OF NINETY-ONE CASES

Excerpt INTRODUCTION For several reasons, the role of bacteria of thePseudomonasgroup in human disease has received increasing attention in recent years.1-5Antimicrobial drugs have reduced morbidit...

Pyrogenicity of Influenza Virus in Rabbits.

During an investigation of the toxicity of influenza virus in rabbits, it was noted that the intravenous injection of infected chorio-allantoic fluid was followed by fever. To study this phenomenon, animals were placed in individual stalls, 3 preliminary rectal temperatures were taken at 30-minute intervals to establish a baseline, and the virus preparation to be tested was then injected into the marginal ear-vein. Rectal temperatures were recorded every 30 minutes throughout an observation period of 6 hours after injection. All glassware and saline solutions used were uncontaminated with bacterial pyrogens. A single pool of chorio-allantoic fluid from embryos infected with the PR-8 strain, having a hemagglutinin titer of 1:1024, 1 was used. One ml of this material consistently caused a rise in temperature beginning l 1/2 to 2 hours after injection, reaching a peak of 3-4°F above the baseline in the next 4 hours, and gradually falling to normal. Although doses as small as 0.025 ml produced fever, the increases in temperature were of a lower order. Normal chorio-allantoic fluid and infected fluid from which the virus particles had been removed by centrifugation at 30,000 R.P.M. or by adsorption on chicken erythrocytes gave no fever. The virus resuspended in normal saline solution produced typical temperature elevations. No fever followed the injection of PR-8 virus neutralized with homologous immune serum. The febrile response in rabbits is independent of the infectivity of the virus but seems to be related to its adsorptive capacity. Heating at 56°C for 30 minutes destroyed the infectivity of PR-8 for chick embryos but a portion of the hemagglutinin was retained (1024 to 128); this material produced definite fever in rabbits. Heating at 62°C for 30 minutes destroyed the hemagglutinin titer and these preparations were then non-pyrogenic.

Comparison of Leukocyte Changes Produced by Pyrogens and by Anaphylaxis in the Guinea Pig.

Summary and Conclusion (1) Changes in circulating leukocytes which occur after anaphylaxis have been compared with those after pyrogen injection. Following both of these reactions, there is immediate leukopenia followed by polymorphonuclear leukocytosis. (2) Two types of response, although superficially very similar, are distinguishable by direct eosinophil counts which reveal uniform rises with anaphylaxis and uniform falls with the pyrogenic reaction. (3) The mechanism of these hematologic changes is not touched upon in the present study. (4) It is concluded that the leukocyte changes after anaphylaxis are not due to pyrogen contamination.

Acquired Resistance to the Shwartzman Phenomenon

Summary and conclusions 1. The resistance to the Shwartzman phenomenon which develops when the reaction is elicited at short intervals is transient, disappearing after a rest period of 21-28 days. 2. This resistance was found to be effective against Shwartzman active materials from heterologous bacterial species. 3. It was found that a transient state of non—reactivity could be produced by repeated inocuilation of bacterial substances intracutaneously, intravenously or intramuscularly, evidence that the resistance is not depeneded on the development of skin hemorrhage. 4. The resistance which develops by repetitive injections could be overcone by in creasing the provocative intravenous dose but not by increasing the preparatory intracutaneous dose. 5. Attempts to transfer this resistance passively with homologous serum were unsuccessful.

Splanchnic Removal of Bacteria from Blood Stream of Pyrogen-Tolerant Rabbits.

Discussion and Conclusions Beeson(2) has shown that in animals made tolerant to the pyrogenic effect of typhoid vaccine, there is an increased disappearance of the pyrogenic material from the blood stream. The increase in disappearance rate is blocked by the administration of thorotrast. He interpreted this as an indication that the reticuloendothelial system removes the pyrogenic material from the blood stream and that it does so with increased efficiency on repeated contact with the pyrogen, thus leaving less and less pyrogen in the blood stream to damage other susceptible tissues. More recent studies by Bennett and Cluff(l) have shown that rabbits made tolerant to pyrogens become non-reactive also to the Shwartzman phenomenon. Both of these effects are blocked by the injection of thorotrast(2,3); as is the removal of bacteria from the blood stream(4). However, although there seem to be some similarities between the characteristics of resistance to the Shwartzman phenomenon and resistance to pyrogen effect, the third effect (i.e. removal of bacteria from the blood) does not show a cross-relationship, at least insofar as alteration of bacterial removal by pyrogen-tolerance is concerned. The extent of splanchnic removal of bacteria from the blood stream of pyrogen-tolerant animals is not significantly different from the removal rate observed in the control groups.