Biomedical subjects
Publications and source records attributed to R A Webb.
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The projections of four anatomically distinct groups of putative neurosecretory cells found within the supra-oesophageal ganglion of the leech Macrobdella decora were studied by intracellular injection of horseradish peroxidase. All four groups have their own characteristic branching pattern while sharing the common feature of possessing primary branches that project into the dorsal commissure. Numerous secondary processes extend from these primary branches to terminate within the neural lamella, as well as within the neuropile. Electron microscopy of the regions into which these secondary processes project reveals numerous neurosecretory terminals. The data suggests that the midregion of the dorsal commissure constitutes a neurohemal complex. These observations strengthen the argument that the four groups of identified cells are indeed neurosecretory.
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An approach to the isolation of neurosecretory material from planarians is described. This material stimulated RNA synthesis, in a dose-dependent response, in regenerating Dugesia tigrina. The data support the concept that neurosecretion plays a key role in the process of regeneration in planarians.
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A retrospective study of the sociocultural and behavioral characteristics of 200 persons under treatment for narcotic addiction was done and the results compared with those of 200 matched nonaddict peers. Twenty-eight of the original 104 items tested were found to discriminate between the two samples at the 5% level of significance. A factor analysis of these items indicated that a general delinquency behavior factor and three family background factors accounted for most of the variance in the data.
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Putative neurosecretory cells were observed with the electron microscope in the nerve cords of the neck region of Hymenolepis microstoma. The cells show evidence of glandular activity by the large numbers of dense-core vesicles produced by the Golgi apparatus. The axons contain synaptoidlike structures with surrounding clouds of vesicles; features analogous to known neurosecretory release sites.
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The fine structure of an unciliated sensory receptor of the metacestode of Hymenolepis microstoma is described. Each receptor contains a basal body inserted into an electron dense matrix; a terminal cilium is lacking. At this stage of development neurotubules were lacking, but rapidly appeared following excystation. It is suggested that neurotubules play a role in the functioning of the putative proprioceptor.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.