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 cytoarchitecture, cytology, and synaptic organization of the basilar pontine nuclei in the rat. I. Nissl and Golgi studies.

Abstract: Studies of the rat basilar pontine gray in Nissl-stained frozen sections revealed the presence of four major subdivisions referred to as medial, ventral, lateral, and peduncular nuclei with respect to their position relative to the cerebral peduncle Neurons located adjacent to the surface of, or within the cerebral peduncle were considered collectively as the peduncular nucleus It should be emphasized that the above subdivisions are useful only for descriptive purposes and do not necessarily reflect distinct cytological similarities or differences within the identified cell groups The dorsal peduncular (pontine) region was continuous around the lateral and medial boundaries of the peduncle with more ventral pontine areas A distinct cluster of neurons was consistently observed near the ventromedial surface of the basilar pons, seemingly walled-off by fascicles of pontocerebellar axons In addition, in most animals, a cleft appeared in the peduncle and allowed direct communication between dorsal and ventral peduncular regions, while the medial lemniscus formed a partial boundary separating dorsal pontine neurons from the nucleus reticularis tegmenti pontis Golgi studies indicated that four general varieties of pontine neurons could be distinguished, and in order of relative frequency were described as spine-laden, pauci-spined, pauci-spined with long, thin dendrites, and small bipolar or unipolar cells whose axon sometimes collateralized within the pons A wide variety of spinous processes and finger-like dendritic protrusions, some of which formed a terminal tuft-like arrangement, characterized pontine neuron dendrites In addition, some dendrites of small neurons gave rise to rather long, thin, beaded processes which in certain instances emanated from an unusual triangulated branch point enlargement Dendritic orientation (neuron shape) was sometimes determined by location, with cells in the peduncular nucleus oriented parallel to the nearest peduncular surface, while cells near the ventral pontine surface were arranged parallel to transversely directed pontocerebellar axons Cells of medial pontine regions did not project dendrites across the midline, while neurons near the peduncular cleft sent dendrites into that space Based on the locations of various pontine afferent termination zones as determined in previous as well as ongoing studies, it appears that some pontine neurons exhibit dendritic systems reaching into more than one afferent projection area, thereby affording them an opportunity to receive inputs from several afferent systems

Does incomplete repair explain the apparent failure of the basic LQ model to predict spinal cord and kidney responses to low doses per fraction

Abstract: Recent evidence indicates that isoeffect doses for spinal cord and kidney may be overestimated for fraction sizes as small as 1 or 2 Gy when calculated from a linear-quadratic (LQ) model fitted to data obtained for fraction sizes larger than 2 Gy. Reasons for this are unknown, but possible interpretations include exhaustion of repair capacity and incomplete repair in experiments designed to study the response to these small doses. The latter interpretation is motivated by the relatively short intervals between multiple daily doses given to the spinal cord (4 h) and kidney (5 h) when fraction sizes were small. The possibility that overestimation of isoeffect dose could be explained by incomplete repair during short intervals between doses was assessed by fitting experimental data to the incomplete-repair model. For the spinal cord the data could be interpreted by assuming that a repair process with a half-time of 1.7 h was incomplete; this half-time is negligibly different from the estimate obtained from repair-kinetics experiments with larger doses per fraction. The deviation from the (complete-repair) LQ model could be interpreted for the kidney in terms of a half-time of repair of 2.8 h (a negligibly different fit was obtained with the value 1.5 h). The clinical implication could be that multiple-fractions-per-day treatment would benefit from use of the longest feasible interfraction interval when late reactions are dose limiting.

Redox and photoinitiator systems for priming and improved adherence of gels to substrates

Abstract: An impoved barrier or drug delivery system which is highly adherent to the surface to which it is applied is disclosed, along with methods for making the barrier. In the preferred embodiment, tissue is stained with a photoinitiator, then the polymer solution or gel having added thereto a defined amount of the same or a different photoinitiator is applied to the tissue. On exposure to light, the resulting system polymerizes at the surface, giving excellent adherence, and also forms a gel in the rest of the applied volume. Thus a gel barrier of arbitrary thickness can be applied to a surface while maintaining high adherence at the interface. This process is referred to herein as "priming". the polymerizable barrier materials are highly useful for sealing tissue surfaces and junctions against leaks of fluids. In another embodiment, "priming" can be used to reliably adhere preformed barriers to tissue or other surfaces, or to adhere tissue surfaces to each other. A first surface and a barrier, or another surface, are prestained with initiator, and a thin layer of gelable monomer containing initiator is placed between them. Strong adhesion is obtained between the two surfaces on gelation of the monomer. In a similar fashion, tissue surfaces can be adhered to each other in repair of wounds and formation of anastomoses. Methods for use of non-photochemical systems and combined chemical/photochemical systems are described.

Woven intravascular devices and methods for making the same

Abstract: Self-expandable, woven intravascular devices for use as stents (both straight and tapered), filters (both temporary and permanent) and occluders for insertion and implantation into a variety of anatomical structures. The devices may be formed from shape memory metals such as nitinol. The devices may also be formed from biodegradable materials. Delivery systems for the devices include two hollow tubes that operate coaxially. A device is secured to the tubes prior to the implantation and delivery of the device by securing one end of the device to the outside of the inner tube and by securing the other end of the device to the outside of the outer tube. The stents may be partially or completely covered by graft materials, but may also be bare. The devices may be formed from a single wire. The devices may be formed by either hand or machine weaving. The devices may be created by bending shape memory wires around tabs projecting from a template, and weaving the ends of the wires to create the body of the device such that the wires cross each other to form a plurality of angles, at least one of the angles being obtuse. The value of the obtuse angle may be increased by axially compressing the body.