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Biomedical subjects

K Ludwig

Publications and source records attributed to K Ludwig.

At least 163 records · Page 9Linked to original sources
PubMed1987

Release and elimination of methylmethacrylate monomer after intraocular lens implantation.

The potential for certain constituents in intraocular lenses, such as monomer methylmethacrylate (MMM), to induce toxic effects after intraocular implantation not only depends on their toxic potency, but also on the characteristics of their release, accumulation, and elimination from the aqueous humor. A mathematical estimation taking these factors into account shows that for a lens mass of approximately 15 mg, the concentration of MMM in the aqueous humor amounts to about 10(-4) of the respective concentration in the lens, but that value is maintained for several weeks. Therefore, experiments to test the chemical toxicity of MMM or similar lens compounds in eyes must not only take into account the actual concentration limit but also the time of exposure to the substance.

Eye↗
PubMed1985

3H-Ouabain binding to human mononuclear leucocytes.

Specific binding of cardiac glycosides to intact human blood cells may be a suitable model for physiological or disease-induced changes in cardiac glycoside binding to human heart muscle. Since the erythrocyte contains no nucleus and has relatively few binding sites compared with heart muscle, intact mononuclear leucocytes were investigated in the present study. Using leucocyte suspensions from 34 normal subjects, 133 measurements of 3H-ouabain binding-were obtained. 3H-Ouabain bound to one type of binding site with an affinity (KD) of 2.8 +/- 1.2 X 10(-9) M, similar to that of human heart muscle. Association and dissociation were slow processes (k+1, 3.9 X 10(4) M-1 sec-1; k-1, 8.1 X 10(-5) sec-1, n = 2). The number of ouabain binding sites/leucocyte varied from 18,000 to 60,000 (mean +/- SD, 34,600 +/- 9,700), with no correlation with the proportion of monocytes present or with the serum K+-level of the donors. Large inter- and intra-individual differences in binding site number were measured which are probably a result of the heterogeneity of the cell suspension used. Thus, the ouabain binding site on human heart muscle and intact mononuclear leucocytes is probably identical. However, the number of binding sites in mixtures of mononuclear leucocytes shows large and inconsistent intraindividual variations, making these studies unsuitable for quantifying drug- or disease-induced changes in ouabain binding site number.

Adult↗
PubMed1984

Chemical studies of intraocular lenses after experimental generation of lesions by a short-pulsed Nd-YAG laser.

It is theoretically possible that lesions generated by a Q-switched Nd-YAG laser could lead to chemical changes in polymethylmethacrylate (PMMA) intraocular lenses. These changes could be of clinical relevance. Therefore, we measured the residual monomer content of intraocular lenses before and after generation of lesions by means of a short-pulsed Nd-YAG laser. Despite the explosive destruction of the lens surface caused by this type of laser, there is no measurable release of monomer in the sense of a depolymerization of the PMMA material, even when over 100 lesions are generated. The lesions generated on intraocular PMMA lenses with the Nd-YAG laser are predominantly of a mechanical nature and include the chipping away of small particles from the intraocular lens.

Lasers↗