University of Texas at Dallas

About: University of Texas at Dallas is a education organization based out in Richardson, Texas, United States. It is known for research contribution in the topics: Population & Computer science. The organization has 14986 authors who have published 35589 publications receiving 1293714 citations. The organization is also known as: UT-Dallas & UT Dallas.

Reduced Hippocampal Functional Connectivity in Alzheimer Disease

Abstract: Objective To determine if functional connectivity of the hippocampus is reduced in patients with Alzheimer disease. Design Functional connectivity magnetic resonance imaging was used to investigate coherence in the magnetic resonance signal between the hippocampus and all other regions of the brain. Participants Eight patients with probable Alzheimer disease and 8 healthy volunteers. Results Control subjects showed hippocampal functional connectivity with diffuse cortical, subcortical, and cerebellar sites, while patients demonstrated markedly reduced functional connectivity, including an absence of connectivity with the frontal lobes. Conclusion These findings suggest a functional disconnection between the hippocampus and other brain regions in patients with Alzheimer disease.

Intensive high-dose asparaginase consolidation improves survival for pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma: a Pediatric Oncology Group study.

Abstract: This study was designed to test the hypothesis that high-dose asparaginase consolidation therapy improves survival in pediatric patients with T cell acute lymphoblastic leukemia and advanced stage lymphoblastic lymphoma. Five hundred and fifty-two patients (357 patients with T cell acute lymphoblastic leukemia (ALL) and 195 patients with advanced stage lymphoblastic lymphoma) were enrolled in POG study 8704 (T-3). Treatment included rotating combinations of high-dose myelosuppressive chemotherapy agents proven to be effective in T cell ALL in other POG group-wide or local institutional protocols (including vincristine, doxorubicin, cyclophosphamide, prednisone, asparaginase, teniposide, cytarabine and mercaptopurine). After achieving a complete remission (CR), patients were randomized to receive or not receive high-dose intensive asparaginase consolidation (25,000 IU/m2) given weekly for 20 weeks by intramuscular injection. Intrathecal chemotherapy (methotrexate, hydrocortisone and cytarabine) was given to prevent CNS disease, and CNS irradiation was used only for patients with leukemia and an initial WBC of >50,000/microl or patients with active CNS disease at diagnosis. CR was achieved in 96% of patients. The high-dose asparaginase regimen was significantly superior to the control regimen for both the leukemia and lymphoma subgroups. Four-year continuous complete remission rate (CCR) for the leukemia patients was 68% (s.e. 4%) with asparaginase as compared to 55% (s.e. 4%) without. For the lymphoma patients, 4-year CCR was 78% (s.e. 5%) with asparaginase and 64% (s.e. 6%) in the controls. The overall one-sided logrank test had a P value <0.001 favoring asparaginase, while corresponding values were P = 0.002 for ALL and P = 0.048 lymphoblastic lymphoma. Toxicities were tolerable, but there were 18 failures due to secondary malignancies (16 with non-lymphocytic leukemia or myelodysplasia). Neither WBC at diagnosis (leukemia patients) nor lymphoma stage were major prognostic factors. We conclude that when added to a backbone of effective rotating agents, repeated doses of asparaginase during early treatment improve the outcome for patients with T cell leukemia and advanced stage lymphoblastic lymphoma.

Sequential molecular abnormalities are involved in the multistage development of squamous cell lung carcinoma

Abstract: To understand the molecular pathways involved in the pathogenesis of squamous cell lung carcinoma, we obtained DNA from 94 microdissected foci from 12 archival surgically resected tumors including histologically normal epithelium (n=13), preneoplastic lesions (n=54), carcinoma is situ (CIS) (n=15) and invasive tumors (n=12). We determined loss of heterozygosity (LOH) at 10 chromosomal regions (3p12, 3p14.2, 3p14.1-21.3, 3p21, 3p22-24, 3p25, 5q22, 9p21, 13q14 RB, and 17p13 TP53) frequently deleted in lung cancer, using 31 polymorphic microsatellite markers, including 24 that spanned the entire 3p arm. Our major findings are as follows: (1) Thirty one percent of histologically normal epithelium and 42% of mildly abnormal (hyperplasia/metaplasia) specimens had clones of cells with allelic loss at one or more regions; (2) There was a progressive increase of the overall LOH frequency within clones with increasing severity of histopathological changes; (3) The earliest and most frequent regions of allelic loss occurred at 3p21, 3p22-24, 3p25 and 9p21; (4) The size of the 3p deletions increased with progressive histologic changes; (5) TP53 allelic loss was present in many histologically advanced lesions (dysplasia and CIS); (6) Analyses of 58 normal and non-invasive foci having any molecular abnormality, indicated that 30 probably arose as independent clonal events, while 28 were potentially of the same clonal origin as the corresponding tumor; (7) Nevertheless, when the allelic losses in the 30 clonally independent lesions and their clonally unrelated tumors were compared the same parental allele was lost in 113 of 125 (90%) of comparisons. The mechanism by which this phenomenon (known as allele specific mutations) occurs is unknown; (8) Four patterns of allelic loss in clones were found. Histologically normal or mildly abnormal foci had a negative pattern (no allelic loss) or early pattern of loss while all foci of CIS and invasive tumor had an advanced pattern. However dysplasias demonstrated the entire spectrum of allelic loss patterns, and were the only histologic category having the intermediate pattern. Our findings indicate that multiple, sequentially occurring allele specific molecular changes commence in widely dispersed, apparently clonally independent foci, early in the multistage pathogenesis of squamous cell carcinomas of the lung.

Widely dispersed p53 mutation in respiratory epithelium. A novel mechanism for field carcinogenesis.

Abstract: Individuals with one aerodigestive tract malignancy have a high incidence of second primary aerodigestive tumors. The mechanism for this field effect has not been determined. We studied an individual with widespread dysplastic changes in the respiratory epithelium but no overt carcinoma. The entire tracheobronchial tree obtained at autopsy was embedded in paraffin, and bronchial epithelial cells were isolated by microdissection. DNA extracted from the microdissected cells was analyzed for point mutations in the p53 tumor suppressor gene. A single, identical point mutation consisting of a G:C to T:A transversion in codon 245 was identified in bronchial epithelium from 7 of 10 sites in both lungs. Epithelium at sites containing the p53 mutation was morphologically abnormal, exhibiting squamous metaplasia and mild to moderate atypia. No invasive tumor was found in the tracheobronchial tree or any other location. Cells from peripheral blood, kidney, liver, and lymph node exhibited no abnormality in the p53 gene. The widespread presence of a single somatic p53 point mutation in the bronchi of a smoker suggests that a single progenitor bronchial epithelial clone may expand to populate broad areas of the bronchial mucosa-a novel mechanism for field carcinogenesis in the respiratory epithelium that may be of importance in assessing individuals for risk of a second primary tumor as well as in devising effective strategies for chemoprevention of lung cancer.