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Biomedical subjects

F Kremer

Publications and source records attributed to F Kremer.

At least 37 records · Page 2Linked to original sources
PubMed1993

Postkeratoplasty myopia treated by keratomileusis.

High myopia and astigmatism may both complicate penetrating keratoplasty and cause difficult problems in the visual rehabilitation of the transplanted eye. There are several treatment options besides contact lens fitting for high postkeratoplasty myopic anisometropia, including radial keratotomy, epikeratoplasty, minus-power anterior chamber lenses, keratomileusis, and excimer laser keratectomy. We present the results of keratomileusis in two patients with postkeratoplasty myopia. This procedure has been proved to yield favorable results with regard to graft clarity, refraction, and final uncorrected and corrected visual acuity.

Adult↗
PubMed1984

Picosecond relaxations in hydrated lysozyme observed by mm-wave spectroscopy.

Dielectric absorption measurements at mm-wave frequencies (50 GHz. . . 150 GHz) are reported for lysozyme at different hydration levels. The measurements were extended over the temperature range from liquid helium to room temperature using the untuned cavity technique. For dried lysozyme (water content less than or equal to 0.5%, w/w) a nearly linear increase with frequency and an exponential increase with temperature of the absorption coefficient is observed between 50 K and 300 K. This frequency and temperature dependence is described by relaxation processes in asymmetric double-well potentials with relaxation times in the picosecond range. Hydration yields a nearly frequency-independent contribution to the absorption, which arises only at temperatures above 120 K. The frequency independence indicates relaxation rates for the bound water that are small compared to mm-wave frequencies. Thereby the contribution of bound water can clearly be distinguished from the fast intrinsic processes. An assignment of these picosecond relaxations to the NH . . . OC hydrogen bond of the peptide backbone is suggested.

Muramidase↗
PubMed1984

Evaluation of the ocular safety of verapamil. Scheimpflug photography with densitometric image analysis of lens transparency in patients with hypertrophic cardiomyopathy subjected to long-term therapy with high doses of verapamil.

The ophthalmic examination of patients with hypertrophic cardiomyopathy treated with high doses of verapamil over a considerable period of time showed no evidence of a side effect of the drug, thus proving its ocular safety. This could be verified by densitometric image analysis of Scheimpflug photographs of the eyes. The data were used for statistical tests on lens transparency. Changes in lens transparency, i.e. a probable drug-induced cataract were found in none of the patients.

Cardiomyopathy, Hypertrophic↗
PubMed1982

8-methoxypsoralen and long ultraviolet effects on the rat lens: experiments with high dosage.

The effect of systemic 8-methoxypsoralen (8-MOP; 100 mg/kg daily) and subsequent long ultraviolet irradiation (UVA; 300 mJ/cm2; peak: 365 nm) on albino and pigmented rat eyes was studied in a 3-dimensional experimental set-up. While 8-MOP and UVA did not cause any ocular pathology when administered alone, a combined application of the two factors caused reversible corneal opacities, and irreversible iris devascularisation and cataracts. The irreversible changes were seen only in the albinos and accompanied by a significant decrease in lens wet weight. Phosphorescence and EPR spectroscopy demonstrated the formation of an 8-MOP-protein photoadduct in the animals treated with both 8-MOP and UVA. The results of this study emphasize the necessity of shielding the eyes of patients on photochemotherapy with protective spectacles.

Animals↗
PubMed1982

[An ocular toxicity study with flupirtine as an example of evaluation of possible ocular drug side effects in human volunteers (author's transl)].

Animal experiments do not provide complete information on all the possible ocular side effects and the toxicity of a new drug. Several functional or dynamic parameters of vision can only be tested in humans as they are either do not exist in laboratory animals or their assessment requires a subjective contribution by the test person. A study was carried out on a new analgesic substance (Flupirtine) in which a large number of such parameters were tested in young healthy volunteers. The results were subjected to statistical analysis with a two-factor partlyhierarchical anova and no toxic effects were detected. The study shows how such parameters of visual function can be tested in humans.

Adult↗