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T Niemann

Publications and source records attributed to T Niemann.

23 records · Page 2Linked to original sources
PubMed1995

Absence of significant germ line p53 mutations in ovarian cancer patients.

Germ line mutations of the p53 gene have been described in the Li-Fraumeni Cancer Family Syndrome and occur in patients with multifocal gliomas, particularly those with a history of a metachronous cancer or a family history of cancer. p53 dysfunction is often associated with ovarian cancer. Patients with ovarian carcinoma frequently develop synchronous or metachronous cancers and may have a family history of this or related cancers. Thus, we hypothesized that germ line p53 mutations might be associated with a significant proportion of ovarian cancers. Germ line DNA isolated from peripheral leukocytes of 73 patients with ovarian carcinoma was screened for p53 sequence abnormalities utilizing single-strand conformation polymorphism analysis and direct PCR sequencing techniques. As many as 40% of this cohort of ovarian cancer patients from 67 families may represent familial phenotypes. Synchronous and metachronous cancers occurred in 19% of the cohort. Only two intron-based polymorphisms were found. Neither has been previously reported. One of these, in intron 6, occurred in three unrelated patients all of whom had a history of metachronous breast cancer. A polymorphism in intron 10 occurred in a patient with synchronous endometrial cancer. No classic germ line mutations of p53 were found.

Base Sequence↗
PubMed1994

Eye movements elicited by transparent stimuli.

A transparent motion condition occurs when two different motion vectors appear at the same region of an image. Such transparency during self-motion has shown demonstrable effects on perception and on the underlying neurophysiology in the cortical and subcortical structures of primates. Presumably such stimulus conditions also influence oculomotor behavior. We investigated smooth-pursuit performance, using a transparent stimulus consisting of two oppositely-moving patterns. We found slight reduction in the mean eye velocity tracking a transparent pattern, compared with that when tracking a unidirectional pattern. Additionally, we investigated the behavior of the optokinetic system to transparency, demonstrating that it elicits antagonistic optokinetic nystagmus, with distinctly reduced gain of the slow phases. Furthermore, we observed, during optokinetic stabilization of transparent stimuli, directional dominances demonstrating that subjects preferably followed one direction. Presenting a transparent stimulus with oppositely moving patterns and different velocities we found a general velocity dominance demonstrating that patterns with a certain velocity are preferred. Performing all experiments under dichoptic conditions produced results comparable with those found under transparent stimulus conditions.

Adult↗
PubMed1992

Neuropsychological impairment in auto-immune disease.

Estimations of the prevalence of central nervous system involvement in patients with systemic lupus erythematosus (SLE) vary from 25 to 75%. In order to assess possible deficits in memory, attention, and/or reaction time, a battery of neuropsychological tests was administered to 15 patients with SLE and to two matched groups of control subjects; eight patients on corticosteroids and 15 healthy controls. The test battery included the Multiple Choice Word Fluency Test (MWT-B), Benton Visual Memory Scale, Syndrome Short Test (SKT; attention and memory), Attention and Concentration Test (d2), Wechsler Adult Intelligence Scale (WAIS) subtests for Comprehension, Digit Span, Block Design, a Computer Controlled Reaction Time task (CCRT), and a Learning and Memory Test (LGT-3). Results revealed a statistically significant short-term memory deficit (for all six relevant subtests used) and a marked delayed simple reaction time in SLE patients as compared with scores in healthy subjects. An attention deficit as well as the expected difference between the estimated premorbid and actual level of intelligence could not be demonstrated. With three exceptions (SKT-9 figural recognition, Benton Visual Memory, and LGT-3 figural recognition), patients treated with corticosteroids did not differ from healthy controls. They also did not differ from SLE patients in any of the parameters tested. It therefore appears that the demonstrated deficit in short-term memory and reaction time in SLE patients may not only be due to the neuropsychiatric manifestation of SLE but possibly also result from medication side-effects.

Adult↗