Release of platelet activating factor (P.A.F.-acether) by isolated perfused rat kidney

Platelet-activating factor (a 1-0-alkyl-2-acetyl glyceryl-3-phosphorylcholine, P.A.F.-acether) causes the aggregation of platelets from various Mammalian species and the release of their granule content. P.A.F.-acether activity has been recovered in vitro from perfused isolated Rat kidneys, stimulated by the ionophore A 23187. The maximum release was reached 10 min. after addition of the ionophore. P.A.F.-acether from kidney exhibited the same physico-chemical and biological characteristics as P.A.F.-acether from leucocytes. These data demonstrate that the kidney secretes a mediator of immediate hypersensitivity (P.A.F.-acether) in the veinous vasculature. Therefore the kidney itself has the ability of inducing intravascular platelet aggregation with subsequent local increase in vasopermeability.     

Activity of precocene analogs onLocusta migratoria migratorioides (R. and F.)

Summary Several analogs of precocene have been synthesized and evaluated as potential inhibitors of juvenile hormone onLocusta migratoria. Only 5,7-dimethoxy-2,2-dimethylchromene was active; its ED₅₀ and LD₅₀ were measured and compared to those of precocene I and II.Acknowledgments. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the Ministère de l'Education du Québec. We are grateful to Gaston Grégoire for rearing the insects.     

Labelling the adults of the tobacco caterpillarSpodoptera littoralis (Boisd.) (Prodenia littura F.; noctuidae: Lepidoptera) with P32

Zusammenfassung Radioaktive Markierung der Larven vonSpodoptera littoralis mittels³²P ist nicht nur in den daraus resultierenden Imagines, sondern auch in den Eiern und den daraus schlüpfenden F1-Räupchen gut nachweisbar.     

The infectivity of polyhedra of nuclear polyhedrosis virus (N.P.V.) after passage through gut of an insectpredator

Polyhedral inclusion bodies (P.I.B) of a nuclear polyhedrosis virus of Heliothis punctigera (Lep.) were found in excreta of Nabis tasmanicus (Het.), a predator of H. punctigera. An immunofluorescent counting method was used to estimate numbers of P.I.B. Bioassays demonstrated that no loss of infectivity occurred during passage through the gut.     

The infectivity of polyhedra of nuclear polyhedrosis virus (N.P.V.) after passage through gut of an insectpredator

Summary Polyhedral inclusion bodies (P.I.B.) of a nuclear polyhedrosis virus ofHeliothis punctigera (Lep.) were found in excreta ofNabis tasmanicus (Het.), a predator ofH. punctigera. An immunofluorescent counting method was used to estimate numbers of P.I.B. Bioassays demonstrated that no loss of infectivity occurred during passage through the gut.Acknowledgment. I am grateful for the comments and criticism offered by Dr D.E. Pinnock, I thank D.J. Cooper for preparation of materials for the immunofluorescent counting method and J. Hardy for supplying me with eggs ofH. punctigera; all of Department of Entomology, Waite Agricultural Research Institute, Glen Osmond, South Australia.     

Attraction ofScolytus scolytus (F.) to the components of Multilure,the aggregation pheromone ofS. multistriatus (Marsham) (Coleoptera: Scolytidae)

Summary The attraction ofS. scolytus to the components of Multilure is described. 4-Methyl-3-heptanol is an attractant which is synergised bya-cubebene. Multistriatin appears to be an inhibitor. A combination of 4-methyl-3-heptanol and cubeb oil is more effective as a bait forS. scolytus than Multilure.We thank Mr A. K. Hughes and Mr J. Boswell for their cooperation in allowing us to conduct experiments on Parham Estate; Mr D. Mobbs and Mr C. Thorne for the statistical analyses; Dr J. W. Peacock for samples of mixed isomers of multistriatin and distilled cubeb oil; Mrs J. Allsop and Mr N. J. Fielding for technical assistance. We are grateful to Mr D. Bevan, Dr J. H. Borden, Dr J. F. Grove and Prof. A. W. Johnson for their interest and encouragement.     

Hemolymph coagulation in Macropipus puber (L.) Crustacea Decapoda. Respective roles of hemolymph and plasma]

The process of coagulation of the hemolymph in Macropipus puber (L.) Crustacea Decapod depends on one or several plasmatic factors and on a thermo-labile cellular factor which does not seem to be specific. The existence of these factors has been demonstrated.     

A beautiful sea: P. A. M. Dirac's epistemology and ontology of the vacuum

This paper charts P.A.M. Dirac's development of his theory of the electron, and its radical picture of empty space as an almost-full plenum. Dirac's Quantum Electrodynamics famously accomplished more than the unification of special relativity and quantum mechanics. It also accounted for the ‘duplexity phenomena’ of spectral line splitting that we now attribute to electron spin. But the extra mathematical terms that allowed for spin were not alone, and this paper charts Dirac's struggle to ignore or account for them as a sea of strange, negative-energy, particles with positive ‘holes’. This work was not done in solitude, but rather in exchanges with Dirac's correspondence network. This social context for Dirac’s work contests his image as a lone genius, and documents a community wrestling with the ontological consequences of their work. Unification, consistency, causality, and community are common factors in explanations in the history of physics. This paper argues on the basis of materials in Dirac's archive that --- in addition --- mathematical beauty was an epistemological factor in the development of the electron and hole theory. In fact, if we believe that Dirac's beautiful mathematics captures something of the world, then there is both an epistemology and an ontology of mathematical beauty.     

Consumption of vitamin A in intact and castrated rats. Relation to tocopherol and cytochrome P 450]

There are significant differences between castrated and non castrated male Rats in regard to vitamine A hepatic storage and plasma level. Cytochrom P 450 levels are the same in both groups. Those results are discussed.     

Identification and electroantennographic activity of sex-specific geranyl esters in an abdominal gland of femaleAgriotes obscurus (L.) andA. lineatus (L.) (Coleoptera,Elateridae)

Summary Both geranyl hexanoate and geranyl octanoate were identified by GC/MS as the major volatiles in a hitherto uncharacterized abdominal gland in females inAgriotes obscurus. Only geranyl octanoate was found inA. lineatus. In EAG tests performed onA. obscurus males, geranyl butanoate and geranyl hexanoate elicited the strongest antennal responses.Financial assistance was donated by The Bank of Sweden Tercentenary Foundation and the Axel and Margaret Ax: son Johnson Foundation. We thank B Baur for statistical advice.     

A peculiar nystagmus and a corresponding foveal structure in the eye of the herring (Clupea harengus L.)

Zusammenfassung An Heringen, die in Aquarien schwimmen, kann ein Nystagmus beobachtet werden. Hierbei rotiert das Auge um eine Achse, die ungefähr senkrecht zur Pupillenebene steht. Der Nystagmus steht wahrscheinlich in Beziehung zu einer fovealen Struktur auf der ventralen Hälfte der Retina. Die Auslösung und Bedeutung «optokinetischer» oder «optomotorischer» Reaktionen wird diskutiert.     

Primary visual centers in the frog (Rana esculenta L.) and the problem of ipsilateral projections. Radioautographic study]

The topographic organization of the frog's primary visual system has been reexamined in Rana esculenta using autoradiographic technique. 10 to 24 hrs following an intraocular injection of tritiated proline, an intense labelling was observed contralaterally in the various retinal projection centres (preoptic area); neuropils of Bellonci; corpus geniculatum of the thalamus; posterior thalamus; posterodorsal preoptic area; magnocellular pretectal nucleus and basal optic nucleus; tectal laminae A to G of Potter), as already described. Furthermore, the presence of a ipsilateral projection within the hypothalamus (preoptic area), the thalamus (neuropils of Bellonci and corpus geniculatum) and the pretectium (posterior thalami neuropil, pretectal optic area) is confirmed. On the other hand, the existence of ipsilateral retinotectal (to Potter's lamina F) and retino-tegmentomescencephalic projections (to the basal optic nucleus), which were thusfar questioned, has been demonstrated.     

Effect of alpha-tocopherol (vitamin E) on the utilization of vitamin A and induction of cytochrome P 450 in rats receiving DDT]

During detoxication processes of DDT, there is, in the Rat, interference between vitamins A and E (D.1.alpha-tocopherol acetate). Vitamin E spares retinal and has a slighter but significant influence on P 450 cytochrome induction. These results are discussed.