Biomedical subjects
Publications and source records attributed to M Halpern.
A device for oral inhalation of test aerosols by rabbits is described. The device allows efficient aerosol delivery to the lower respiratory tract in unanesthetized animals for studies of the bronchial airway responses to inhaled particles.
A modified method for nebulization was developed for use with relatively small (20 mL) amounts of feed liquid, in this case, a suspension of radioactively tagged polystyrene (CMD = 2.87 micron, sigma g = 1.25). The method may be easily adapted for use in producing other aerosols where only this quantity of suspension material is available.
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A source of efferent fibers to the eye of snakes of the genus Thamnophis has been identified by the use of the retrograde transport of horseradish peroxidase. Cell bodies of the contralateral nucleus of the ventral supraoptic decussation accumulate horseradish peroxidase after intraocular but not intraorbital injections. Intraocular injections also result in anterograde transport of horseradish peroxidase to retinofugal axon terminals. Intraorbital injections result in accumulation of horseradish peroxidase in the cell bodies of the cranial nerve nuclei of extraocular muscles.
The efferent connections of the olfactory bulb and accessory olfactory bulb of two species of garter snakes, Thamnophis sirtalis and T. radix were studied with experimental anterograde degeneration techniques. Axons of cells located in the olfactory bulb terminate ipsilaterally in all parts of the anterior olfactory nucleus, olfactory tubercle and lateral pallium. In addition, some axons enter the ipsilateral stria medullaris thalami, cross the midline in the habenular commissure, enter the contralateral stria medullaris thalami and terminate in the contralateral lateral pallium. The axons of cells in the accessory olfactory bulb course through the telencephalon completely separated from the fibers of olfactory bulb origin and terminate predominantly in the nucleus sphericus. These results confirm previous reports of the separation between the central projections of the olfactory and vomeronasal systems in a variety of vertebrates. The totality of the separation between these two systems coupled with the extensive development of the vomeronasal-accessory bulb system in these snakes suggests that they may be ideal subjects for further research on the functional significance of the vomeronasal system.
Two cases of symptomatic renal angiomyolipoma are presented, and their distinctive clinical, radiologic, and histologic features are discussed. In the first case the scout film demonstrated radiolucency of the tumor which helped to distinguish it from carcinoma. In the second case, which was associated with tuberous sclerosis, the renal lesion was large and unifocal, and the local lymph nodal involvement with tumor raised the possibility of malignant transformation.
Using a Y-maze apparatus, nine garter snakes were trained to follow an earthworm-extract trail. Correct trailing improved significantly as training progressed. All snakes were able to attain a trailing criterion of 8 out of 10 correct trials by the termination of training. For each trial, the number of tongue flicks each snake made was recorded and tongue flick rate calculated. Tongue flick rate was found to be highly characteristic and constant for individual subjects. In addition, running speed and tongue flick rate were found to be significantly correlated.
Following unilateral enucleation of blind snakes, serial sections of the brains were stained by the Fink-Heimer procedure; the sections revealed terminal degeneration in the lateral geniculate nucleus of the thalamus bilaterally, nucleus posterodorsalis of the pretectum bilaterally, and superficial layers of the contralateral optic tectum. The stained degenerating fibers in the tectum were considerably less dense than in the thalamus.
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