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Biomedical subjects

C Hartmann

Publications and source records attributed to C Hartmann.

At least 145 records · Page 8Linked to original sources
PubMed1989

[In vitro changes in the lens epithelium and corneal endothelium caused by the cytostatic drug daunomycin].

We evaluated the effects of the antiproliferative drug daunomycin on the viability and proliferation of cultured porcine lens epithelial cells. After a single short-term application, daunomycin penetrates the lens epithelial cells within 5 min. At a concentration of 2.5-7.5 mg/l, daunomycin has a low level of acute cytotoxicity and significantly suppresses the mitotic activity of the epithelial cells in culture. The daunomycin-induced endothelial lesions in freshly excised pig corneas were quantified with the Janus green photometry technique (n = 30) and studied with scanning electron microscopy (n = 9) in comparison to Ringer solution, which served as the control (n = 39). Whether the endothelial lesions were exposed to daunomycin or Ringer solution for 10 or 30 min seemed to make no significant difference. In addition, daunomycin did not seem to induce any morphological changes in the endothelial surface. These in vitro results confirm our clinical experience that daunomycin is apparently not harmful to the adult human corneal endothelium. Our results indicate that short-term endocapsular application of daunomycin during extracapsular cataract extraction, with or without IOL implantation, may prevent and/or delay the formation of capsular opacification.

Animals↗
PubMed1989

[In vitro corneal endothelial damage caused by intraocular lenses of PMMA, silicone and polyhema].

We compared the endothelial damage to freshly excised pig corneas (n = 156) as a result of contact with IOLs made of PMMA, silicone and polyhema. The contact time was 15 s, 1 min and 30 min. The endothelial damage was quantified with the Janus green vital staining photometric technique. Morphological changes were evaluated by scanning electron microscopy. The most damage was caused by PMMA (7.6%; 10.2%; 19.7%), followed by silicone (4.8%; 6.8%; 10.2%) and polyhema (4.6%; 5.9%; 8.3%). The degree of endothelial damage was statistically significant (P less than 0.01) in comparison with the control groups without any relationship to lens material or contact time. There was no significant difference between the damage caused by silicone and polyhema, but there was a significant difference between PMMA and silicone or polyhema.

Animals↗
PubMed1988

[One year after Chernobyl. Cesium-137 levels in premature, newborn and nursing infants and in younger and older children of Bonn and environs].

From May to August 1987, 137Cs activity was measured in a total-body counter (4 pi counter) in 33 premature and mature newborns (group I), 40 infants and young children up to 2 4/12 years of age (group II), and 15 children between 3 and 6 8/12 years (group III), all from Bonn or its environs. The mean of measurements in group II, at 3.7 Bq/kg body-weight, was lower than that of group I (5.8 Bq) and III (9.4 Bq). Mean radiation exposure, calculated from these data, was 1.7 mrem/a for group I, 1.1 mrem/a for group II, and 2.8 mrem/a for group III. A comparison with present Cs values in adults and measurements made at the end of the 1950's and beginning of 60's showed good agreement. There were no significant differences, as regards Cs activity, between newborns or infants who had been formula-fed or breast-fed. The measured radiation exposure of the three groups is about 1% of natural radiation exposure. Thus, present-day results indicate that there will be no damage to health outside the natural scatter.

Accidents↗
PubMed1988

Evaluation of daunomycin toxicity on lens epithelium in vitro.

Posterior capsule opacification is the major complication of extracapsular cataract extraction (ECCE). Lens epithelial cells derived from the periphery of the lens are thought to migrate posteriorly and contribute significantly to the postoperative proliferations at the posterior pole. We have evaluated the effects of the antiproliferative drug daunomycin on cultured porcine lens epithelial cell viability and proliferation. We observed that the mitotic activity of the cells is suppressed by a single short time treatment with daunomycin at a concentration as low as 2.5 mg/l. Long term effects on the reproductive capacity of the lens epithelial cells may not be as pronounced as the inhibition of other cells examined before e.g. retinal pigment epithelium and fibroblasts. Our results indicate that daunomycin may be useful for the pharmacologic prevention of postoperative proliferations in patients treated by ECCE.

Animals↗
PubMed1988

Endothelial alterations in AIDS with cytomegalovirus infection.

We report on a patient in whom a cytomegalovirus infection occurred in connection with AIDS. Together with the alterations of the fundus typical for cytomegalovirus retinitis, reticular deposits were observed on the corneal endothelium. Specular microscopy showed occasional endothelial cells with edema, as well as small, dark, round, mobile structures (probably lymphocytes) and large, bright, spindle-shaped, immobile structures (probably macrophages) located behind the endothelium. Despite treatment with corticosteroids and acyclovir, an increase in the extent of the findings was observed. The deposits are interpreted as a reaction of the endothelium to the cytomegalovirus infection.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Pyrroloquinoline quinone: a new redox cofactor in eukaryotic enzymes.

During the past decade pyrroloquinoline quinone has been shown to be a new redox cofactor for a range of bacterial alcohol dehydrogenases. Recent studies suggest that this cofactor may also be covalently bound to the active site of the eukaryotic copper amine oxidases. In this mini-review we present the evidence in support of pyrroloquinoline quinone as a novel eukaryotic cofactor. As a result of mechanistic advances during the last three years, together with a re-examination of previously existing data, a working model for the role of pyrroloquinoline quinone in enzyme-catalyzed amine oxidation reactions can be proposed.

Animals↗
PubMed1987

Reductive trapping of substrate to bovine plasma amine oxidase.

Plasma amine oxidases catalyze the oxidative deamination of amines to aldehydes, followed by a 2e- reduction of O2 to H2O2. Pyrroloquinoline quinone (PQQ), previously believed to be restricted to prokaryotes, has recently been proposed to be the cofactor undergoing reduction in the first half-reaction of bovine plasma amine oxidase (Ameyama, M., Hayashi, U., Matsushita, K., Shinagawa, E., and Adachi, O. (1984) Agric. Biol. Chem. 48, 561-565; Lobenstein-Verbeek, C. L., Jongejan, J. A., Frank, J., and Duine, J. A. (1984) FEBS Lett. 170, 305-309). This result is unexpected, since model studies with PQQ implicate Schiff's base formation between a reactive carbonyl and substrates, whereas experiments with bovine plasma amine oxidase have failed to provide evidence for a carbonyl cofactor. We have, therefore, re-examined putative adducts between substrate and enzyme-bound cofactor, employing a combination of [14C]benzylamine and [3H]NaCNBH3. The use of the relatively weak reductant, NaCNBH3, affords Schiff's base specificity and permits the study of enzyme below pH 7.0. As we show, enzyme can only be inactivated by NaCNBH3 in the presence of substrate, leading to the incorporation of 1 mol of [14C]benzylamine/mol of enzyme subunit at complete inactivation. By contrast, we are unable to detect any labeling with [3H]NaCNBH3, analogous to an earlier study with [3H]NaCNBH4 (Suva, R. H., and Abeles, R. H. (1978) Biochemistry 17, 3538-3545). We conclude, first, that our inability to obtain adducts containing both carbon 14 and tritium rules out the reductive trapping either of amine substrate with pyridoxal phosphate or of aldehyde product with a lysyl side chain and, second, that the observed pattern of labeling is fully consistent with the presence of PQQ at the active site of bovine plasma amine oxidase.

Amine Oxidase (Copper-Containing)↗
PubMed1987

Diffuse epithelial ingrowth after perforating keratoplasty.

Diffuse epithelial ingrowth was observed in 2 patients after perforating keratoplasty. Both cases involved a corneal graft after perforating injury with aphakia. In the first patient, the epithelial invasion was probably stimulated by a spatula synecholysis. In this case, the diagnosis was only made by histological investigation after enucleation. In the second patient the epithelial ingrowth was observed 8 months after keratoplasty. The clinical diagnosis was made on the basis of the typical slitlamp findings. In this case, the epithelial invasion led to hypotension with high resistance of outflow measured by electrotonography. In a very close chronological relation to the probable fall of chamber fluid secretion, development of a band-shaped keratopathy was observed.

Adult↗
PubMed1987

Aromatase activity in monolayer cell cultures of human endometrium.

Monolayer cell cultures of proliferative human endometrial stromal cells were incubated with 100 nCi 3H-androstenedione or 100 nCi 3H-testosterone for 15 hours. After termination of the incubations 16% of the recovered radioactivity was identified as estrone by thin layer chromatography and subsequent recrystallization. 3H-testosterone was almost quantitatively converted to 3H-androstenedione. 3H-dihydrotestosterone remained unmetabolized. These findings indicate a highly active 17 beta-ol-dehydrogenase and a high aromatizing capacity of human endometrial cells.

Androstenedione↗