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Biomedical subjects

A Ihme

Publications and source records attributed to A Ihme.

13 recordsLinked to original sources
PubMed1984

[Results of cyclocryocoagulation in chronic narrow-angle glaucoma].

Cyclocryocoagulation is successful in 86% of eyes with narrow-angle glaucoma, i.e., intraocular pressure is lowered to a maximum of 23 mm Hg with or without additional local therapy postoperatively. Therefore, this procedure represents a real alternative to the fistulating operation, especially with regard to prevention of malignant glaucoma. One interesting observation was the postoperative widening of the chamber angle. It is still not known whether the pressure-lowering effect is caused not only by a reduction in aqueous production but also by an improvement in outflow.

Aged↗
PubMed1984

Ehlers-Danlos syndrome type VI: collagen type specificity of defective lysyl hydroxylation in various tissues.

The Ehlers-Danlos syndrome type VI is an inherited disorder of collagen metabolism characterized by a defective lysyl hydroxylase. The resulting lack of hydroxylysine has been found in several connective tissues, all of which show varying degrees of clinical symptoms. In the present study, collagen was isolated from different connective tissues and the degree of hydroxylation of lysyl residues was determined. Subsequently, collagen types I, II, III, IV, and V have been prepared from a number of tissues. Insufficient hydroxylation of lysyl residues was found in type I and type III collagen, whereas types II, IV, and V showed normal amounts of hydroxylysine. The expression of the defect, even for type I and type III collagen, varied widely from one tissue to another. A complete lack of hydroxylysine was observed in skin, while it was less pronounced in tissues such as bone, tendon, lung, or kidney. The data suggest the presence of several isoenzymes having varying affinities to the different collagen types.

Adult↗
PubMed1983

Biochemical investigation of cells from keratoconus and normal cornea.

Collagen is the major structural protein in the cornea. In keratoconus the central cornea is thin, opaque and weak. Collagen synthesis was investigated in cells derived from the stroma of cornea with keratoconus and from controls. No difference was found in the ratio of collagens type I and type III synthesized, which were investigated as procollagens and after conversion to collagen as well. The alpha 1/alpha 2 ratio in type I collagen was similar in keratoconus cells and controls.

Cells, Cultured↗
PubMed1983

[Shape of filtration blebs and pressure regulation after trabeculectomy].

The authors describe the results of trabeculectomy in 90 eyes: in 85% the IOP was between 10 and 22 mm Hg with or without additional therapy. About 60% of these eyes had a flat cystic bleb, about 20% were incisible and 20% bullous. The eyes with an IOP of 23 mm Hg or more also had well-formed filtration blebs. No correlation was found between the shape of the filtration blebs and the IOP.

Follow-Up Studies↗
PubMed1983

Biochemical characterization of variants of the Ehlers-Danlos syndrome type VI.

Three variants of the Ehlers-Danlos syndrome type VI are described: a severe form with skeletal, dermal and ocular manifestations associated with a lack of hydroxylysine in skin and little lysyl hydroxylase activity in cultured fibroblasts; a similarly affected form with a nearly normal hydroxylsine content in skin, but with only little enzyme activity in cultured fibroblasts; and a predominantly ocular form with no biochemical abnormality in skin or cultured skin fibroblasts. The activities of prolyl 4-hydroxylase and the two hydroxylysyl glycosyltransferases were normal in all cases, and the failure to find lysyl hydroxylase activity was not due to altered solubility characteristics of the enzyme or to the presence of an enzyme inhibitor. The collagen produced in cell culture, however, was hydroxylated to a markedly higher extent than that found in skin. In both the mutant and control cells hydroxylation of lysyl residues was less sensitive to ascorbate deficiency than that of prolyl residues.

Adolescent↗
PubMed1982

Molecular defects in inborn disorders of collagen metabolism.

Disturbances of collagen metabolism may result in the manifestation of clinical symptoms. The collagen disorders that best characterized are genetically inherited and are known to vary at the clinical and molecular levels. Defective posttranslational modifications of collagen chains due to mutant enzymes have been found in patients with the Ehlers-Danlos syndrome and cutis laxa. Altered selection of collagen types and defective primary structure of the molecules themselves are prominent features in osteogenesis imperfecta. In other pathological conditions, such as Marfan syndrome, no clear molecular defect has been identified as yet.

Collagen↗
PubMed1980

[Ehlers-Danlos-Syndrome. Heterogeneity and molecular causes of the disease picture].

Progress in the experimental field and a deepened understanding of biological functional entities gave considerable impetus to connective tissue research. This was particularly true for the heritable connective tissue disorders, of which the Ehlers-Danlos-Syndrome is the best example. Its clinical and biochemical heterogeneity have allowed a classification of the disease into sub-groups, and the conditions for differential diagnosis and therapeutic trials were thus improved.

Collagen↗