PubMed Health⌕ Search

Biomedical subjects

A Bangert

Publications and source records attributed to A Bangert.

3 recordsLinked to original sources
PubMed2004

[Intraocular epithelial downgrowth - report on 14 cases from 1986 to 2000].

BACKGROUND: Diffuse and cystic epithelial downgrowth occur rarely, but they represent a mostly preventable potential cause of blindness as sequels to trauma and surgery. The aim of this study is to report on the etiology and course of disease in patients with histologically verified epithelial downgrowth. PATIENTS AND METHODS: From 1986 until 2000 the ophthalmopathological laboratory of the University Eye Hospital Hamburg-Eppendorf received 13 (4 external) referrals. Ten patients with cystic of diffuse intraocular epithelial downgrowth were treated and 9 eyes were operated on in the Hospital. RESULTS: At presentation 4/10 patients had a visual acuity of < or = 0.1, and 2/10 had no light perception. A cystic epithelial downgrowth was verified histologically in 9/13, and a diffuse form in 4/13 patients. Mucin production was proven histochemically in 1/9 intraocular epithelial downgrowth sections. In one case a spontaneous iris cyst was detected by the immunohistological examinations. Trauma (10/14) and surgery (3/14) were the most frequent causes and were symptomatic on average 17 years after the primary event. A curative surgery was done in 13/14 patients (5 x en bloc excision, 2 x penetrating keratoplasty, 1 x iridectomy, 2 x enucleations, 3 x external) resulting in no recurrences during the follow-up of 4(1/2) years (1 - 12 years). The postoperative visual acuity was ameliorated in 5/9, worsened in 2 patients, and 2 were enucleated. CONCLUSIONS: Epithelial downgrowth is a rare but preventable cause of blindness. The most important prophylaxis is meticulous primary surgery including a sufficient wound closure. The visual outcome depends on the preoperative conditions.

Adolescent↗
PubMed2001

The representations of the arithmetic operations include functional relationships.

Current theories of mathematical problem solving propose that people select a mathematical operation as the solution to a problem on the basis of a structure mapping between their problem representation and the representation of the mathematical operations. The structure-mapping hypothesis requires that the problem and the mathematical representations contain analogous relations. Past research has demonstrated that the problem representation consists of functional relationships, or principles. The present study tested whether people represent analogous principles for each arithmetic operation (i.e., addition, subtraction, multiplication, and division). For each operation, college (Experiments 1 and 2) and 8th grade (Experiment 2) participants were asked to rate the degree to which a set of completed problems was a good attempt at the operation. The pattern of presented answers either violated one of four principles or did not violate any principles. The distance of the presented answers from the correct answers was independently manipulated. Consistent with the hypothesis that people represent the principles, (1) violations of the principles were rated as poorer attempts at the operation, (2) operations that are learned first (e.g., addition) had more extensive principle representations than did operations learned later (multiplication), and (3) principles that are more frequently in evidence developed more quickly. In Experiment 3, college participants rated the degree to which statements were indicative of each operation. The statements were either consistent or inconsistent with one of two principles. The participants' ratings showed that operations with longer developmental histories had strong principle representations. The implications for a structure-mapping approach to mathematical problem solving are discussed.

Adolescent↗