University of Texas System

About: University of Texas System is a education organization based out in Austin, Texas, United States. It is known for research contribution in the topics: Cancer & Population. The organization has 13901 authors who have published 10925 publications receiving 319328 citations. The organization is also known as: UT System.

The auditory corticopontocerebellar projection in the rat: inputs to the paraflocculus and midvermis. An anatomical and physiological study

Abstract: This study investigated afferent projections to the cerebellum, in particular those from the auditory cerebral cortex. The parafloccular lobule of the rat cerebellum is shown to be a primary target for the auditory cortical information with the midvermal region being a receiving area from the inferior colliculus. The method of anterograde transport of tritiated amino acids was employed to determine projections of the auditory cortex to the pons. Autoradiography showed that the site of termination of efferents from the auditory cortex corresponds to the location of neurons that project to the paraflocculus. Histogram analysis of neuronal activity in halothane anesthetized rats was employed to determine the response characteristics of neurons in paraflocculus and midvermis following cortical and tectal electrical stimulation. In addition, unit recordings of parafloccular neurons in immobilized, locally anesthetized animals demonstrated general characteristics of the responses of these neurons to auditory field stimulation. Electrical stimulation of the auditory cortex evoked mixed, excitatory-inhibitory and pure inhibitory mossy fiber responses in 33% of neurons in the paraflocculus, with no responses evident in the midvermis. Following inferior collicular stimulation, 12.6% of the neurons in the midvermis elicited a response. Recordings from parafloccular neurons in unanesthetized, immobilized rats showed evidence for excitatory and inhibitory mossy fiber responses, following auditory field stimulation. This spectrum of basic studies establishes the existence of a pathway in which the paraflocculus is revealed as an integrating target for cortical auditory information.

Vasoocclusion coil device having a core therein

Abstract: A coil-type vasoocclusion device (10) for establishing an embolus or vascular occlusion in a human or veterinary patient is adapted for introduction into the patient via a catheter (32). The device (10) first includes a coil (12) having proximal and distal coil ends (16, 18) and a coil lumen (20). The device (10) also includes a core (22) disposed in at least part of the coil lumen (20), the core having proximal and distal core ends (24, 26). Only one core end (24 or 26) is directly affixed to a respective end (16 or 18) of the coil (12); the other core end (26 or 24) is not directly connected to either end (16 or 18) of the coil (12). The core (22) is preferably nitinol in a superelastic state, being in other than its stress induced, martensitic condition. The device (10) can include a thrombogenic material (38) connected to or carried by the coil (12). The coil (12) is preferably adapted to achieve a suitable secondary shape (60) when deployed from the catheter (32). A medical device (40) combining the catheter (32), a pusher (34), a coupling (30) and the vasoocclusion device (10) is also disclosed. The vasoocclusion device (10) is easily repositioned in the vascular system, thereby ensuring proper deployment, and also enjoys a dislodging force about twice as great as comparable coil-type devices lacking the core (22), substantially or completely preventing migration of the device (10) after its deployment.

Effects of catechol estrogens and catecholamines on hypothalamic and corpus striatal tyrosine hydroxylase activity.

Abstract: The effects of catechol estrogens on tyrosine hydroxylase activity in hypothalamic and corpus striatal extracts were evaluated. When assayed in the presence of subsaturating concentrations of pterin cofactor, tyrosine hydroxylase activity was depressed by 2-hydroxyestrone, 2-hydroxyestradiol, Lnorepinephrine, or dopamine. However, estrone, 17β-estradiol, 2- methoxyestrone, or 2-methoxyestradiol had no consistent inhibitory effect on tyrosine hydroxylase activity under in vitro conditions. Moreover, a decrease in pterin binding affinity (elevated Km) in the presence of either catecholamines or 2-hydroxyestrogens was found. These findings were suggestive of a competitive interaction between catechols and pterin. Catechol estrogens and catecholamines were shown to inhibit both membrane-bound and soluble forms of tyrosine hydroxylase. The membrane-bound form of tyrosine hydroxylase, however, was found to have a greater binding affinity (lower Kl) for 2hydroxyestradiol and norepinephrine than did the soluble form. The results of the present study are suggestive of a cytoplasmic effect of estrogen that may be mediated by 2-hydroxyestrogen and terminated by O-methylation.