PubMed Health⌕ Search

Biomedical subjects

P Schlecht

Publications and source records attributed to P Schlecht.

16 recordsLinked to original sources
PubMed1995

[Multiple keratosis induced by hydroxyurea].

INTRODUCTION: Specific skin manifestations including skin atrophy and stripes of erythema on the extremities have been reported in patients with long-term treatment with hydroxyurea (HU). CASE REPORT: A 60-year-old patient who had been treated with HU since 1986 for chronic myeloid leukaemia presented in March 1992 with lesions characteristic of HU-induced skin changes. Hydroxyurea was continued for two more years and the lesions worsened. Unusually encountered multiple skin keratoses developed rapidly creating a clinical picture compatible with carcinomatous transformation until the withdrawal of hydroxyurea. DISCUSSION: The chronology and the clinical signs were in favour of implicating hydroxyurea in the development of these keratoses. The literature on the subject revealed one comparable case with actinic keratoses and multiple skin carcinomas. The interactions between hydroxyurea and the keratinocytes of the basal layer could explain different aspects of hydroxyurea-related toxidermia. The most severe manifestation could be the development of epithelial skin cancer.

Female↗
PubMed1987

Photoreconvertible fluorophore systems in rhabdomeres, Semper cells and corneal lenses in the compound eye of the blowfly.

1. The primary aim of the experiments described in this article was to localize the origin of the complex fluorescence in the compound eye of flies. The eye tissue was dissected and the fluorescence from cells and cell organelles was recorded by microspectrofluorometry. Using this technique, fluorophore systems were detected in the rhabdomeres, Semper cells and corneal lenses. The fluorophore systems are photoreconvertible by UV and blue light. 2. The fluorophore systems in the rhabdomeres and Semper cells are similar. The intensity of the fluorescence from the microvilli is enhanced up to 29 X by adaptation to UV light. The enhancement is inversely related to the rhodopsin content in the microvilli, indicating that the chromophoric group of the fluorophore is not a vitamin A derivative. 3. The enhancement of the fluorescence by UV light strongly depends on pH, suggesting that the photoreconvertible fluorophore systems in the microvilli and Semper cells are photosensitive redox pigments. These redox systems are probably located in the membranes of the microvilli in the photoreceptors, and in the endoplasmic reticulum of the Semper cells, or they are coupled to filaments in the cytoskeleton of both cell types. 4. Preliminary reaction schemes for the photoreactions based on the recorded excitation and emission spectra and photokinetics were developed. A primary pigment in the microvillous structure, AR, or in organelles in the Semper cells, AS, is converted by UV light into an excited state AR* or AS*, which either relaxes to the primary pigment by photon emission, or converts into an intermediate X, which by proton uptake changes into stable products, BR or BS. Blue illumination converts BR and BS into the excited states BR* and BS*, which either relax by photon emission to BR or BS, or convert into an intermediate Y, which after deprotonation reconverts into the primary pigment AR or AS. 5. Estimation of the molecular density showed that the concentration of the fluorophore in the microvilli presumably is almost equal to maximal rhodopsin concentration. The high density suggests that the fluorophores have a specific function in transduction or adaptation of the visual process.

Animals↗
PubMed1980

Spectral transmission of the ocular media of the pegion (Columba livia).

Spectrophotometric and microspectrophotometric measures of relative spectral transmission were obtained from the cornea, lens, and vitreous body and from the whole eye of young and adult pigeons. Transmission was above 90% throughout the visible spectrum and was maintained at or above 50% into the near-UV at 310 nm. No age-related changes in transmission were found. The results concur with the pigeon's behavioral UV-detection abilities.

Age Factors↗
PubMedDate not supplied

[Alzheimer's disease and informed consent of incapacitated people: propositions aimed at improving the procedure].

Ethical considerations must be given priority when deciding whether or not to include an Alzheimer's Disease patient in a study leading to direct individual benefits. Although the law applies to ethics, the Huriet-Serusclat law was nevertheless written in the spirit of the major ethical declarations of the last 50 years (Nurenberg, Helsinki, Tokyo...) in order to protect patients from abusive decisions, whether these decisions were for or against the patient receiving treatment. This paper describes an incident during a phase II trial involving patients with Alzheimer's Disease. Four incapacitated patients protected by guardianship had given their informed consent to take part in the study. Their participation required that the informed consent be signed by the guardian as well. By misunderstanding of the law, the guardian transmitted the decision to the guardianship judge. Surprisingly, the guardianship judge refused permission for all patients to take part in this therapeutic trial against the wishes of the patients. Even more surprisingly, it appeared clearly that this judge was not thoroughly informed of each detail of the law. Prevention of this kind of situation might require modifications of the responsibilities of the CCPPRB. It is suggested that before the start of a study the CCPPRB should give a precise definition of the way in which incapacitated persons should be treated.

Aged↗