PubMed Health⌕ Search

Biomedical subjects

J Hanaway

Publications and source records attributed to J Hanaway.

At least 19 recordsLinked to original sources
PubMed1979

Synaptic fine structure and the termination of corticospinal fibers in the lateral basal region of the cat spinal cord.

The lateral basal region (LBR) of the spinal cord gray matter (Rexed's laminae IV-VII) by physiologic and anatomic criteria is the major terminal zone for the corticospinal (CS) tract in the cat. The neurons in this area are medium-sized with abundant spines on their dendrites. Axon terminals on the dendrites and somata of these neurons form synapses easily classified as asymmetric with spheroid vesicles and symmetric with flattened vesicles. There are rare exceptions to this. In a systematic count of terminals, 82% have spheroid and 18% flattened vesicles. The majority of all terminals are on dendrites (84.9%) and a minority on somata (14.1%). Less than 1% are axoaxonic. Degeneration of the corticospinal tract was produced by transecting one hemisphere of our experimental cats. Its termination in the lower cervical cord was studied for 17 hours to 7 days after surgery. Vesicle depletion and clumping and dense polymembranous inclusions were the most common forms of degeneration. Filamentous proliferation in the terminals was also prominent; dark degeneration, however, was infrequent. The percent of degenerating CS terminals in the LBR was the following: 17 hours - 2.2%, 36 hours - 4.19%, 2 days - 10.3%, 3 days - 8.4%, 4 days - 6.9%, 7 days - 10.25%; 84.8% of degenerating CS terminals were axodendritic and 15.2% axosomatic.

Animals↗
PubMed1979

A double constriction micropipette for the quantitative injection of tracer substance.

A glass, double constriction injector micropipette ('micropet') has been designed to overcome problems associated with commercial microliter syringes. These problems include: inconsistent volume delivery, inability to view tracer during filling or injection, and the relatively large size of the needle supplied. 'Micropets' of different volumes are easily made from inexpensive, commercially available Drummond 100 microliter glass tubes (bores) fitted with teflon plungers. Tracer substances may be viewed in the bores during filling and injection and the needle tip can be pulled as small as 50 micrometers. For deep stereotactic injection, a long triple constriction 'micropet' has also been devised. The 'micropet' is based in principle on the commercial Lang-Levy double constriction micropipettes and these are used for radiometric calibration of the 'micropets'. Thus the 'micropet' accuracy is a reflection of these commercial micropipettes, and is approximately +/- 0.5%. Precision is also on the order of +/- 0.5% as determined by radioassay. When combined with an oil-filled, variable-speed microdrive the injector 'micropet' provides a highly controlled and precise system for the accurate delivery of tracer substance important for quantitative neuroanatomical investigations.

Animals↗
PubMed1979

Functional anatomy of the cerebral cortex by computed tomography.

The authors describe the morphological characteristics that allow recognition of the individual computed tomography slice and determine its sequence in the series. In addition, each slices is "assembled" by defining the different cortical gyri, sulci, and cortical functional areas (based on Brodmann's maps). This work lays the foundation for correlative studies of location of lesions and the clinical picture.

Brain↗
PubMed1978

Fine structure of the rubrospinal terminals in the cervical cord of the cat.

Rubrospinal fibers in cat do not terminate on anterior motor horn cells in the spinal cord but on the interneurons, mostly in the lateral portion of Rexed's lamina of V-VII, the so-called Lateral Basal Region. The ultrastructure of rubrospinal terminals at the cervical cord level (C8) was investigated in 8 adult cats with partial or complete stereotaxic lesions of the red nuclei. Animals were sacrificed from 1 to 7 days after the lesions were made and the earliest forms of degeneration found were infrequent dense preterminal axon changes and clumping and coalescing of synaptic vesicles in the terminals. Multiple dense or polymembranous inclusions were seen in some terminals and these contained vesicular profiles; dense terminal shrinking was seen in others after 24 hours. Neurofilamentous proliferation appeared in some degenerating terminals after 48--72 hours. Degenerating terminals were related to different sized dendrites to determine regional axodendritic specificity for rubrospinal endings on LBR neurons.

Animals↗