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Biomedical subjects

P Simmons

Publications and source records attributed to P Simmons.

64 records · Page 4Linked to original sources
PubMed1982

A comparison of the inhibitory effects of prostacyclin and carbacyclin on platelet adhesion to collagen.

The effect of carbacyclin, a chemically stable analogue of prostacyclin (PGI2), on the adhesion of platelets to collagen has been examined. The compound was compared to PGI2 which is unstable and rapidly hydrolysed to the inactive derivative, 6-oxo-PGF 1 alpha. The adhesion of 111Indium-labelled human platelets to collagen in the absence of platelet aggregation and secretion was measured. The cAMP level in the platelets was also monitored. Both PGI2 and carbacyclin inhibited platelet-collagen adhesion and caused a rise in the platelet cAMP level. Carbacyclin was approximately 15-fold less effective than PGI2, however, its effect was longer lasting, remaining constant for at least 30 minutes.

Blood Platelets↗
PubMed1977

The neuronal control of dragonfly flight. I. Anatomy.

The mechanical action and innervation of the major flight muscles of dragonflies are described. All flight muscles investigated are innervated by at least 3 motor neurones and one by as many as 15. Cell bodies of motor neurones that innervate the same muscle are clustered together and have similar, widespread dendritic branching patterns. Motor neurones of leg muscles have greater variety in cell body size and position than the major flight motor neurones. Striking similarities between the positions of cell bodies of motor neurones in dragonflies and the positions of homologous motor neurones in other insects raise interesting questions about the evolution of insect nervous systems.

Animals↗