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Biomedical subjects

M Wiesner

Publications and source records attributed to M Wiesner.

18 recordsLinked to original sources
PubMed2002

Long term behavioural outcome after neonatal arterial switch operation for transposition of the great arteries.

AIMS: To evaluate behavioural outcome and quality of life in children aged 8-14 years after neonatal arterial switch operation for transposition of the great arteries. METHODS: Sixty children operated as neonates with combined deep hypothermic circulatory arrest and low flow cardiopulmonary bypass were evaluated at age 7.9-14.3 years by the Child Behaviour Checklist (CBCL) and the Inventory for the Assessment of the Quality of Life in Children and Adolescents (IQCL). RESULTS: Parent reported behavioural outcome on all CBCL problem and competence scores was worse, whereas quality of life on self reported IQCL scores was not reduced compared to the normal population. On multivariate analysis, severe preoperative hypoxia was related to parent reported social problems; peri- and postoperative cardiocirculatory insufficiency was associated with internalizing, externalizing, attention, and total behavioural problems. Reduced expressive language was associated with total behavioural problems, and poor academic achievement was related to parent reported deficits in school performance. Impaired neurological status and reduced endurance capacity both predicted self reported stress by illness. CONCLUSIONS: The neonatal arterial switch operation with combined circulatory arrest and low flow bypass is associated with parent reported long term behavioural impairment, but not with self reported general reduction in quality of life. This discrepancy may be a result of different perception of illness. In our experience, increased risk of long term psychosocial maladjustment after neonatal corrective cardiac surgery is related to the presence of neurological impairment and reduced endurance capacity.

Adolescent↗
PubMed2001

Application of strontium isotopes for tracing landfill leachate plumes in groundwater.

We are evaluating strontium isotopes as alternative tracers of landfill leachate in groundwater. The municipal landfill studied here is located in southeastern France. This landfill has no bottom liner, and wastes are placed directly on the ground. Based on the evaluation of chloride concentration, the plume extends a maximum of 4,600 m. Strontium isotopic composition characterizes two sources: natural groundwater (87Sr/86Sr = 0.708175) and landfill leachate contamination (87Sr/86Sr = 0.708457). The evolution of mixing ratios obtained with strontium reveals a second source of groundwater contamination: fertilizers (87Sr/ 86Sr = 0.707859). These results suggestthat isotopic signatures can be used to provide useful information on sources of groundwater contamination where conventional water quality parameters may yield ambiguous results.

Environmental Monitoring↗
PubMed2001

Solid-phase synthesis of a nonpeptide RGD mimetic library: new selective alphavbeta3 integrin antagonists.

The solid-phase synthesis of a low molecular weight RGD mimetic library is described. Activities of the compounds in inhibiting the interaction of ligands, vitronectin and fibrinogen, with isolated immobilized integrins alphavbeta3 and alphaIIbbeta3 were determined in a screening assay. Highly active and selective nonpeptide alphavbeta3 integrin antagonists with regard to orally bioavailability were developed, based on the aza-glycine containing lead compound 1. An important variation is the substitution of the aspartic amide of 1 by an aromatic residue. Furthermore, different guanidine mimetics have been incorporated to improve the pharmacokinetic profile. Exchange of the beta-amino acid NH by a methylene moiety in one set of RGD mimetics leads to the azacarba analogue compounds representing a novel peptidomimetic approach, which should increase the metabolic stability.

Amidines↗
PubMed2000

Synthesis and biological evaluation of integrin antagonists containing trans- and cis-2,5-disubstituted THF rings.

The synthesis of a series of RGD mimetics is described. All compounds consist of a central 2,5-disubstituted tetrahydrofuran core, a variable linker to a guanidino group, and a beta-amino alanine unit to mimic the carboxylic acid. Three types of linkers were investigated: a simple four-atom methylene chain (type A, compounds 14, 15, 16, and 17), a four-atom methylene chain with an additional chiral center, and a nitrogen substituent (type B, compounds 38, 39, and 40), and an amide linker of different length with an additional chiral center (type C, compounds 59, 60, 61, and 62). A variety of compounds were tested as potential integrin antagonists in a receptor binding assay (alphaIIbbeta3, alphavbeta3, and alphavbeta5). The relative and absolute configuration of the chiral centers at the THF ring had a pronounced effect on the binding activity and selectivity. Compound 14 proved to be a selective inhibitor of alphaIIbbeta3 (IC50=20nM), whereas compound 40 exhibited high activity for binding of alphaIIbbeta3 (IC50=67nM) and alphavbeta3 (IC50=52nM).

Antineoplastic Agents↗
PubMed1999

[Ranking of 20 MHz sonography of malignant melanoma and pigmented lesions in routine diagnosis].

PURPOSE: Eleven dermatology clinics from all over Germany took part in our multicenter prospective study with the aim of evaluating 20 MHz sonography in the preoperative diagnosis of malignant melanomas and other pigmented skin tumours. It was to be assessed how effective sonographic measurement of thickness would compare to histology and the clinical palpation of tumour thickness and also the significance of differential diagnosis in sonography of malignant melanomas. METHOD: The prospective multicenter study proceed as follows. To the end of August 1997 264 patients with a primary malignant melanoma and 417 patients with benign skin tumours were examined via 20 MHz sonography. Two different examiners estimated the clinical thickness of the tumour by palpation. The tumour was then excised and examined for postoperative correlation with the histology sections. RESULTS: The final results showed good correlation between the histological and sonographic estimation of tumour thickness (r = 0.97). Estimation of tumour thickness by palpation showed no correlation with the histology (r = 0.59). Most of the benign (44%) and malignant tumours (38.7%) were spindle shaped. There was no significant difference between the benign and malignant tumour groups in relation to the sonographic presented shapes or echo signs. No different diagnosis could be made. CONCLUSION: The technique of high frequency sonography in relation to preoperative diagnosis of malignant melanomas has high priority. In contrast to clinical estimation of tumour thickness, sonography provided a good correlation to histology. The effectiveness of sonography with regard to the valence of the skin tumours is limited and there is no possibility of differentiating between malignant and benign tumours from the morphological face value. Hence, there is a demand for developing a 150 MHz apparatus which will be able to supply evidence regarding the valence of skin tumours.

Diagnostic Tests, Routine↗
PubMed1998

Determination of Structure of Aggregates by Confocal Scanning Laser Microscopy.

The fractal dimension of a particle aggregate can provide fundamental information on the structure and origin of the aggregate. The analysis of large chemically homogeneous fractal objects has been achieved, but reliable methods of estimating the fractal dimensions of large and chemically heterogeneous aggregates are needed. To this end, we used confocal scanning laser microscopy in which thin optical sections of aggregates were obtained in order to calculate their 2D and ultimately 3D fractal dimensions according to the Mandelbrot theory. Fractal dimensions of 2.08 +/- 0.11 for a Brownian aggregation of latex particles and 2.25 +/- 0.12 for shear aggregation were determined using the confocal technique. These values are within the ranges for universality classes predicted for such aggregates and observed by previous investigators. Thus, this method appears to provide reliable estimates of the fractal dimension with particular utility in the characterization of aggregates composed of larger particles or complex materials where the fractal dimension may not be accessible by light-scattering measurements. The confocal method is used to analyze flocs of activated sludge material as one example of the application of this method to more complex, large (up to 500 µm), and chemically heterogeneous flocs. Copyright 1998 Academic Press.

Journal Article↗
PubMed1992

[Local corticosteroid therapy in childhood].

Various dermatoses require the application of topical glucocorticoids (gc) already in childhood. There are mostly inflammatory and frequently chronic skin diseases. In necessary long-term therapy the risk of topical and/or systemic side effects increases. This depends among others on special features of the children's skin, the potency of the gc and the mode of application. To avoid side effects, variations of a discontinuous therapy and so called weak gc should be used.

Administration, Topical↗
PubMed1991

Correlations among WISC-R IQs and several measures of receptive and expressive language for children referred for Special Education.

For 42 children from rural north central Kansas school districts (27 boys, 15 girls) who were referred for Special Education testing, the WISC-R IQs (Full Scale, Verbal, and Performance), the means on the Expressive One Word Picture Vocabulary Test, the Peabody Picture Vocabulary Test--Revised, and the Test of Language Development were recorded from the children's files. No sex differences on any variable were noted; all variables correlated (Pearson) significantly but varied in magnitude. This group of tests, being intercorrelated, can be used to collect information on children's academic, speech, and language abilities. Valid judgments can be made regarding children's academic abilities for school when multiple tests are administered by professional staff.

Child↗
PubMedDate not supplied

[Use of hearing aids by the elderly: correlation between intention and behavior].

Hearing in old age has negative consequences for elderly hearing impaired individuals. Most important in aural rehabilitation is the fitting of hearing aids. Problematic is the low use of hearing aids by elderly hearing impaired individuals. Therefore, in the present study predictors of hearing aid use will be analyzed. The theory of planned behavior was used in a sample of 54 men and women with presbyacusis (54-87 years old) for the prediction of hearing aid use. The analyses revealed that actual hearing aid use is influenced mainly by the intention to use hearing aids and by normative beliefs of the person. The intention to use hearing aids is influenced mainly by the attitude towards using hearing aids. Practical implications of the results are discussed: Aural rehabilitation possibly can be improved by changing attitudes toward hearing aid use and asking important members of the social network to participate actively in the aural rehabilitation process.

Aged↗