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Two juvenile pigtailed macaques (animals 1 and 2) received total body irradiation (TBI) followed by autologous stem cell transplantation, by a procedure known to be well tolerated by baboons. In this procedure, the TBI consisted of treatment on two consecutive days with 255 cGy on one side, followed after 1–2 min by a similar dose on the other side. The two pigtailed macaques showed rapid haematopoietic engraftment, but succumbed either to systemic cytomegalovirus (CMV) infection and necrotising colitis or to haemorrhagic cystitis and tubulointerstitial nephritis. For four further pigtailed macaques (animals 3–6) the radiation procedure was changed to four equal doses of 255 cGy, given 6–12 h apart. Animals 4–6 all showed engraftment and survived for long periods (>218 days), with no, or only minor treatable, complications. Animal 3 failed to show engraftment and succumbed to radiation-induced vascular lesions and severe multiorgan haemorrhages. The results suggest that pigtailed macaques have a lower tolerance threshold than baboons, rhesus macaques or human beings to TBI, the adverse effects of TBI being indistinguishable from those seen in human patients. The results also suggest that a hyperfractionated radiation procedure can prevent radiation-induced morbidity and mortality in pigtailed macaques.

The purpose of this article is to examine factors contributing to defense of the bovine lung from microbial infection. Appropriate physical, cellular, and secretory defense components are assessed. Attention is paid to the thin line separating host-mediated defense from host-mediated injury of the lung.

Platelet activating factor is a multifaceted mediator of inflammation capable of stimulating platelet aggregation as well as anaphylaxis, neutropenia and numerous other in vitro and in vivo cellular changes. This lipid mediator, or autocoid, is released by a wide variety of inflammatory cells following an equally diverse group of cellular stimuli including phagocytosis or antigenic stimulation. The synthesized form of PAF is acetyl glyceryl ether phosphorylcholine (AGEPC). In this study AGEPC aggregated bovine platelets in a dose dependent manner. Maximal, irreversible aggregation occurred at 3.6 × 10 −11 M AGEPC with unwashed platelets and at 8.8 × 10 −12 M AGEPC with washed platelets. Aggregation failed to occur when platelets were tested with the biologically inactive structural analog of AGEPC. The possible contribution by platelet cyclooxygenase products was eliminated by showing lack of platelet aggregation to arachidonic acid and also by pretreating platelets with aspirin.