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.

Melatonin reduces gamma radiation-induced primary DNA damage in human blood lymphocytes

Abstract: Peripheral blood samples were collected from human volunteers 5–10 min before, and at 1 and 2 h after a single oral dose of 300 mg of melatonin At each time point: (1) the concentration of melatonin in the serum and in the leukocytes was determined; and (2) the whole blood was exposed in vitro to 100 cGy of gamma radiation Immediately after exposure to the radiation, the lymphocytes were examined to determine the extent of primary DNA damage, viz, single strand breaks and alkali labile lesions (determined from the length of DNA migration and fluorescence intensity of migrated DNA in the comet tail), using the alkaline comet assay For each volunteer, the results showed a significant increase in the concentration of melatonin in the serum and in the leukocytes at 1 h after the oral dose of melatonin, as compared to the sample collected at 0 hour The lymphocytes in the blood samples collected at 1 and 2 h after melatonin ingestion and exposed in vitro to 100 cGy gamma radiation exhibited a significant decrease in the extent of primary DNA damage, as compared with similarly irradiated lymphocytes from the blood sample collected before melatonin ingestion The extent of the melatonin-associated decrease in primary DNA damage did not correspond with the decrease reported earlier in the incidence of chromosomal aberrations and micronuclei; the latter assays required an additional postirradiation incubation of the cells at 37±1°C for 48 and 72 h, respectively

Cancer treatment methods using antibodies to aminophospholipids

Abstract: Disclosed are the surprising discoveries that aminophospholipids, such as phosphatidylserine and phosphatidylethanolamine, are stable and specific markers accessible on the luminal surface of tumor blood vessels, and that the administration of an anti-aminophospholipid antibody alone is sufficient to induce thrombosis, tumor necrosis and tumor regression in vivo. This invention therefore provides anti-aminophospholipid antibody-based methods and compositions for use in the specific destruction of tumor blood vessels and in the treatment of solid tumors. Although various antibody conjugates and combinations are thus provided, the use of naked, or unconjugated, anti-phosphatidylserine antibodies is a particularly important aspect of the invention, due to simplicity and effectiveness of the approach.

A New Ghost Cell/Level Set Method for Moving Boundary Problems: Application to Tumor Growth

Abstract: In this paper, we present a ghost cell/level set method for the evolution of interfaces whose normal velocity depend upon the solutions of linear and nonlinear quasi-steady reaction-diffusion equations with curvature-dependent boundary conditions. Our technique includes a ghost cell method that accurately discretizes normal derivative jump boundary conditions without smearing jumps in the tangential derivative; a new iterative method for solving linear and nonlinear quasi-steady reaction-diffusion equations; an adaptive discretization to compute the curvature and normal vectors; and a new discrete approximation to the Heaviside function. We present numerical examples that demonstrate better than 1.5-order convergence for problems where traditional ghost cell methods either fail to converge or attain at best sub-linear accuracy. We apply our techniques to a model of tumor growth in complex, heterogeneous tissues that consists of a nonlinear nutrient equation and a pressure equation with geometry-dependent jump boundary conditions. We simulate the growth of glioblastoma (an aggressive brain tumor) into a large, 1 cm square of brain tissue that includes heterogeneous nutrient delivery and varied biomechanical characteristics (white matter, gray matter, cerebrospinal fluid, and bone), and we observe growth morphologies that are highly dependent upon the variations of the tissue characteristics--an effect observed in real tumor growth.

Postoperative irradiation in malignant epithelial tumors of the parotid

Abstract: From 1954 through 1979, 77 patients with malignant tumors of the parotid gland were referred from the Department of Head and Neck Surgery for postoperative irradiation. The analysis has been made by grouping the patients according to the estimated amount of disease left after the surgical procedure and by the histological types. There were no local failures in the low-grade tumors, and there were 6 in the 63 patients with high-grade tumors. With gross residual disease or potential residual disease the patients received slightly higher doses than those without. Although there were only 6 failures in the various histological types, there was perhaps a trend to more failures in the adenocarcinomas. There was no difference in the failure rates in patients having had a total resection of the facial nerve or partial resection or no resection. The preferred treatment has been a combination of 20 MeV photons and 18 MeV electrons. Five neck failures were essentially a result of lack of elective irradiation of the neck. Severe complications appeared only in the patients irradiated either for gross residual disease or excision of a recurrence with a high risk of widespread microscopic residual disease.

Composition of A-150 tissue-equivalent plastic

Abstract: In recent years, the use of tissue-equivalent materials has become quite common in fast-neutron dosimetry, with the A-150 plastic developed by Shonka et al. probably the most popular. Information on this specific plastic is scantily reported in the literature and as a consequence a preponderance of authors unknowingly reference an article by Shonka describing an early version of a tissue substitute plastic but having a different elemental composition than the present A-150 formulation. We have reviewed the results of 21 chemical analyses which have occurred over a time span of four years on a total of 14 samples of A-150 plastic and based on these data and the formulation of the plastic, have arrived at a suggested composition for A-150 tissue-equivalent plastic. The ambiguities of water absorption by nylon, one of the components of the plastic, and the uncertainty this reflects in the composition of the plastic were evaluated.