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Biomedical subjects

C Anderson

Publications and source records attributed to C Anderson.

At least 631 records · Page 35Linked to original sources

On the mechanism of action of clonidine: effects on single central neurones.

1 Noradrenaline and clonidine were applied by microiontophoresis to single neurones in the cerebral cortex and medullary reticular formation of anaesthetized rats.2 Of a total of 247 neurones studied, 79% of medullary units and 60% of cortical units responded in the same manner to both noradrenaline and clonidine. The usual response was a depression of neuronal firing rate.3 It proved possible to antagonize some responses to both substances by the microiontophoresis of bulbocapnine, whilst leaving unaffected similar responses to 5-hydroxytryptamine.4 On 13% of the cells, clonidine produced an increase of firing rate. This effect could not be attributed to a post-synaptic antagonism of tonically released endogenous noradrenaline, but may indicate a presynaptic action of clonidine, reducing noradrenaline release.5 These observations are thought to support the idea that clonidine may have an agonist action on noradrenaline receptors in the brain.

Animals↗

Conditional lethal mutants of adenovirus 2-simian virus 40 hybrids. I. Host range mutants of Ad2+ND1.

Human adenovirus type 2 (Ad2) grows poorly in monkey cells, although this defect can be overcome by co-infection with simian virus 40 (SV40). The nondefective Ad2-SV40 hybrid virus, Ad2(+)ND1, replicates efficiently in both human and African green monkey kidney cells, presumably due to the insertion of SV40 sequences into the Ad2 DNA. Several mutants of Ad2(+)ND1 have been isolated that grow and plaque poorly in monkey cells, although they retain the ability to replicate and plaque efficiently in HeLa cells. One of these mutants (H39) has been examined in detail. Studies comparing the DNA of the mutant with Ad2(+)ND1 either by the cleavage patterns produced by Escherichia coli R.RI restriction endonuclease digestion or by heteroduplexing reveal no differences. The pattern of protein synthesis of Ad2(+)ND1 and H39 in monkey cells is quite different with the mutant resembling Ad2, which is defective in the synthesis of late proteins. However, in human cells, the proteins synthesized by H39 and the parent Ad2(+)ND1 are very similar. The production of SV40 U antigen in H39-infected cells is different from that in Ad2(+)ND1-infected cells. Finally, the growth of H39 in monkey cells can be complemented by SV40.

Adenoviridae↗

Isolation and preliminary characterization of bacteriophages for Bdellovibrio bacteriovorus.

Ten bacteriophages that attack and lyse saprophytic strains of Bdellovibrio bacteriovorus were isolated. Morphological, serological, and host-range studies revealed that there were four different bdellovibrio phages present among the isolates. One of the phages lysed a strain of B. bacteriovorus that requires the presence of a suitable bacterial host for growth. The phage attached to the bdellovibrio cells in the absence of the bacterial host cells; lysis occurred only in the presence of host cells. The 19 saprophytic bdellovibrio strains employed in the phage host-range studies were grouped on the basis of their susceptibility to phage lysis.

Antigens, Viral↗