The effects of acute bleeding on acid-base balance erythropoietin (Ep) production and in vivo P50 in the rat

The mechanism of erythropoietin (Ep) production after acute haemorrhage has been thought to be due to a reduction in blood volume and tissue perfusion leading to tissue hypoxia. In the present study we have evaluated the effect of acute haemorrhage in the rat on the acid-base status, the red cell affinity for oxygen in vivo, and Ep production. Within a few hours after acute blood loss there was a respiratory alkalosis with an increase in blood pH, a decrease in pCO2 and an increase in the red cell affinity of Hb for oxygen in vivo that was temporally related to an increase in Ep production. Within 24 h after the acute haemorrhage, the blood pH AND PCO2, red cell affinity for oxygen in vivo, and Ep level returned towards normal. The decrease in in vivo red cell affinity for oxygen was associated with an increase in red cell 2,3-DPG levels and a decrease in Ep production.

Functional and Structural Similarity Between Human C5 and a Component of Bovine Milk

Maximum opsonization of baker's yeast particles by normal human serum requires C5. Sera from mice genetically lacking C5 are deficient in yeast opsonic activity but can be restored to normal by addition of highly purified human C5. Human, animal, proprietary and soy milks are comparable to human C5 in opsonic reconstitution of C5-deficient mouse serum. This reconstitution by each milk is inhibited by highly purified anti-human C5. Further characterization of the opsonically active principle(s) in milk has been carried out by comparison of bovine milk with human C5 in the following assays: 1) effective molecular titration of hemolytically active C5 in plasma or milk by lysis of EAC14oxy23 cells in the presence of C6-9; 2) generation of chemotactic activities by addition of endotoxin or antigen-antibody complexes; 3) heat stability of opsonic activity; 4) inhibition of opsonic reconstitution by milk or plasma of C5-deficient mouse serum by addition of highly purified anti-C5, anti-C3, or anti-immunoglobulins; and 5) chromatographic separation.

SECA, a new mediator of the human eosinophil response

Spontaneous eosinophilic chemotactic activity (SECA) present in human sera can mediate the directed movement of normal human eosinophils. Our data utilize normal peripheral blood eosinophils obtained from subjects with 500 eosinophils/m3 or less. SECA is defined as that chemotactic activity for eosinophils present in serum that has been heat-inactivated immediately after collection. It was demonstrated in patients with severe chronic eczema with eosinophilia (20 to 30%); mixed collagen vascular disease with vasculitis; clinical serum sickness; acute glomerulonephritis, and chronic membranoproliferative glomerulonephritis. Control sera were obtained from normal, healthy individuals. The data indicated: (1) that SECA in patient sera was significantly higher than in control sera; (2) when activated by endotoxin, no additional chemotactic activity was generated from patient sera over that spontaneously present--by contrast, addition of endotoxin to control sera did result in increased chemotactic activity; (3) sera from patients with extrinsic bronchial asthma had no SECA.

Hemodialysis leukopenia and polymorph random mobility-a possible correlation

In vitro studies of polymorphs exposed to cellulose and polysulfone membranes showed severe impairment in randommobility with the cellulose membrane. In vivo studies with the two membranes showed that profound leukopenia occurred only when cellulose membrane was used. It is suggested that random mobility may have importance in the regulation of peripheral polymorph levels.

Phagocytic, opsonic and immunoglobulin studies in newborns

Despite improved diagnositc and therapeutic measures, neonatal septicemia continues to be a major clinical problem. Improvement in the management of the septic neonate should result from application of the increasing information being learned of the neonatal host defense mechanisms. The earlier concept that the neonate was "immunologically null" can now be discarded. Evidence summarized in this review has established that the neonate can marshal an immune response to most antigens and infectious agents.A further major advance in recent years has been in understanding of the inflammatory response in the neonate, which includes such activities as chemotaxis, phagocytosis and bactericidal killing of ingested bacteria by phagocytes.