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Biomedical subjects

R L Van Buskirk

Publications and source records attributed to R L Van Buskirk.

10 recordsLinked to original sources
PubMed1996

A manipulative technique of Andrew Taylor Still as reported by Charles Hazzard, DO, in 1905.

This article presents rediscovered osteopathic manipulative techniques described by Charles Hazzard in 1905 and ascribed by him to Andrew Taylor Still, the founder of osteopathic medicine. Still refrained from writing about his manipulative techniques in any significant detail, apparently intentionally. The techniques published by Hazzard have both internal consistency and similarity to those less well described by Still, suggesting that the attribution is accurate. The techniques are analyzed and presented as a variant of a direct articulatory technique with axial compression. In honour of their originator, they are being termed the Still techniques.

Humans↗
PubMed1990

Nociceptive reflexes and the somatic dysfunction: a model.

A model of somatic dysfunction is developed in which restriction in mobility and autonomic, visceral, and immunologic changes are produced by pain-related sensory neurons and their reflexes. Nociceptors are known to produce muscular guarding reactions, as well as autonomic activation, when musculoskeletal or visceral tissue is stressed or damaged. This guarding causes abnormal musculoskeletal position and range of motion. Local inflammatory responses and autonomic reflexes further reinforce nociceptor activity, maintaining restriction. Nociceptive autonomic reflexes also evoke changes in visceral and immunologic function. Finally, maintenance of muscles, joints, and related tissues in an abnormal guarding position causes changes in the connective tissues, solidifying the abnormal position. Stretching these tissues into a normal range of motion will restimulate the nociceptor, reflexly reinforcing the somatic dysfunction. This model has evolved from Korr's neurologic model but emphasizes the nociceptor and its reflexes as a source of the connective tissue, circulatory, visceral, and immunologic changes seen in the somatic dysfunction.

Bone and Bones↗
PubMed1983

Subcortical auditory and somatosensory afferents to hamster superior colliculus.

To determine whether the pattern of superior colliculus (SC) afferents seen in cat is generalizable to other mammalian species, HRP was injected into the SC of twenty hamsters (Mesocricetus auratus). After reaction with TMB, subcortical structures were examined for labeled perikarya. Although most subcortical afferents to SC were similar in cat and hamster, there were differences in auditory and somatosensory SC innervation. In hamster only two putatively auditory structures showed labeled cells, the external nucleus of inferior colliculus and nucleus of the brachium of the inferior colliculus, whereas in cat additional cells are reported in the dorsal cochlear nucleus, trapezoid and superior olivary nuclei, and nucleus of the lateral lemniscus. Again, in hamster the major trigeminal somatosensory input to SC is from spinal trigeminal nucleus caudalis whereas in cat trigeminal input is reported to be from the principalis and oralis portions of the trigeminal nucleus. Thus the hamster possesses a very restricted auditory input to and a different pattern of somatosensory innervation of the SC relative to the cat.

Afferent Pathways↗
PubMed1983

Gustatory neuron types in hamster brain stem.

In general, mammalian taste neurons are broadly responsive to stimuli representing different taste qualities. In the hamster, this breadth of tuning increases systematically from peripheral to successively higher brain stem neurons. Some investigators have classified taste-responsive neurons into "best-stimulus" categories on the basis of which of the four basic stimuli (sucrose, NaCl, HCl, or quinine hydrochloride) elicits the maximum response. However, attempts by others to demonstrate the existence of taste neuron types in the chorda tympani nerve and medulla of the rat using hierarchical cluster analysis have not been successful, resulting in the conclusion that there are no neuron types in the rat gustatory system. The present study was designed to look at the question of neuron types in the hamster, a species with a broader range of gustatory sensitivities to anterior tongue stimulation. Responses of 30 neurons in the nucleus tractus solitarius (NTS) and 31 neurons in the parabrachial nuclei (PbN) of the hamster to an array of 18 stimulus compounds were recorded extracellularly. The similarities of the neural response profiles of these cells at each synaptic level were compared using multivariate statistical techniques. The possiblee grouping of cells on the basis of similarities in their response functions was examined with hierarchical cluster analysis, and the relationships among these response functions were examined with multidimensional scaling. The results of the cluster analysis suggested that at both the NTS and PbN, there are three clusters of neural response profiles. These three clusters of response profiles are characterized at both synaptic levels by their predominant sensitivity to 1) sucrose and other sweet-tasting compounds, 2) sodium salts, and 3) nonsodium salts and acids. Representation of these neurons in a two-dimensional space yielded three nonoverlapping groups of cells in both the NTS and PbN, corresponding to the three groups identified by the hierarchical cluster solution. Classification of taste neurons either by their best stimulus or by other criteria has been criticized on the grounds that it may constitute an arbitrary division of a continuous population of neurons. The techniques of numerical taxonomy, which take the cells' variability into account, also result in a grouping of taste cells into classes. These taxonomic classes agree in most instances (80% in NTS and 80.6% in PbN) to a best-stimulus classification. The failure of some investigators to find types of neural response profiles in the rat gustatory system may be the result of species differences in taste sensitivity as well as differences in the statistical procedures employed.

Acids↗
PubMed1977

Odorant responses in taste neurons of the rat NTS.

In the experiment reported in this paper, 22 of 35 neurons in the gustatory NTS were found to respond to odorant as well as taste stimuli. This odorant response was apparently mediated by the ethmoid nerve and at least one other odorant-responsive system, possibly other nasal trigeminal afferents. These gustatory neurons responded to odorants, as they did to taste stimuli, in a manner consistent with an encoding of stimulus quality information. Thus at least some of the neurons of the gustatory NTS carry information concerning several of the senses involved in ingestion.

Acetone↗
PubMedDate not supplied

Brainstem correlates of gustatory similarity in the hamster.

Responses of neurons in the nucleus tractus solitarius (NTS) and parabrachial pons (Pb pons) of the hamster to 10 gustatory stimuli were compared to behavioral similarities among these compounds. Animals were given a conditioned taste aversion to one of the 10 stimuli by pairing it with an induced gastrointestinal illness. Following this procedure, the degree of generalization of the learned taste aversion to each of the other compounds was measured. Behavioral similarity profiles were derived for each stimulus from the similarities in the generalization profiles of each pair of compounds. The across-neuron correlations in the firing rates evoked by these stimuli in the NTS cells corresponded quite well to these behavioral profiles, as did these neural correlations among Pb pontine cells, except for those correlations involving quinine. Sucrose-best cells in the Pb pons are too broadly responsive to account for the behavioral similarity functions for sweet-tasting stimuli, although other best-stimulus categories of cells (NaCl- and HCl-best) showed response profiles quite similar to the behavioral profiles, as did all best-stimulus classes of cells in the NTS.

Animals↗