Serological diagnostics in the detection of IgG autoantibodies against human collagen VII in epidermolysis bullosa acquisita: a multicentre analysis.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a rare, potentially devastating autoimmune disease of the skin. IgG autoantibodies directed against type VII collagen (Col7), the major component of anchoring fibrils, induce skin fragility leading to cutaneous and mucocutaneous blister formation, which is mostly of a scarring phenotype. Thus, powerful and reproducible diagnostic assays are critical to establish the diagnosis of EBA early to avoid irreversible sequelae. OBJECTIVES: The present international, retrospective multicentre study included a large cohort of patients with EBA and evaluated the diagnostic power of four different diagnostic assays for the detection of anti-Col7 IgG autoantibodies. METHODS: Overall, 95 EBA sera and 200 control sera consisting of 100 bullous pemphigoid sera, 50 pemphigus vulgaris sera and 50 sera of healthy controls were tested for anti-Col7 IgG autoantibodies using indirect immunofluorescence (IIF), two commercial enzyme-linked immunosorbent assay (ELISA) systems and Western blot (WB) analysis. EBA sera were taken from patients with positive direct immunofluorescence and IgG reactivity in at least one of the immunoserological assays (IIF, ELISA, WB). RESULTS: A Col7-NC1/NC2 ELISA (MBL, Nagoya, Japan) showed the highest sensitivity (97·9%), followed by a Col7-NC1 ELISA (Euroimmun, Lübeck, Germany) (89·5%), WB with Col7-NC1 (85·3%), and IIF on saline-split human skin (74·7%). The specificities of both ELISA systems were comparable (NC1 98·7%, NC1/NC2 99·3%). Furthermore, WB was more sensitive than IIF, which was more specific. CONCLUSIONS: The two commercially available ELISA systems allow for a highly sensitive and specific diagnosis of EBA. The sensitivity of the Col7-NC1/NC2 ELISA is significantly higher compared with the ELISA based on the Col7-NC1 domain only.

Effect of calcium ions on pyruvate carboxylase from pigeon liver.

Pigeon liver pyruvate carboxylase (pyruvate: CO2 ligase (ADP forming), EC 6.4.1.1) shows allosteric properties similar to those of chicken or rat liver enzyme. Kinetic methods have been used to determine the effect of Ca2+ on this enzyme. The Ca2+ activation effect is absolutely dependent on the Mg2+ concentration; in the absence of Mg2+, pyruvate carboxylase has no catalytic activity. Furthermore, Ca2+ cannot replace Mg2+ and also shows a paradoxical effect on the liver enzyme activity. It is an activator at low pyruvate or Mg2+ concentrations; at increased pyruvate concentrations, however, it becomes an inhibitor. At low levels of ATP a pronounced activation of pigeon liver pyruvate carboxylase by Ca2+ has been demonstrated. The results of this communication demonstrate pigeon liver pyruvate carboxylase to be different from pyruvate carboxylase from other sources.

[Plastome dependent pollen sterility inOenothera]. / Plastomabhängige Pollensterilität beiOenothera.

Pollen in which the genome complexesflavens (derived fromOe. suaveolens) orgaudens (derived fromOe. lamarckiana) are combined withparviflora plastids (plastome IV) fails to germinate even though it is well developed otherwise. This inability to germinate, however, is not always complete. Those exceptional pollen grains which do germinate do not get this ability by a change of their genome. The germination rate varies modificatively. Furthermore it has clearly been demonstrated that the degree of sterility is influenced by the genotype of the sporophyte. But this influence of the diploid sporophyte on the haploid gametophyte does not go as far as to completely suspend differences in germination behaviour of pollen with plastome IV on the one hand and of (normal) pollen with other plastome types on the other hand.

Chloral hydrate mediated inhibition of cell division and of proton synthesis.

Chloral hydrate (along with other anaesthetics and hypnotics) is an inhibitor of cell division. We have shown that chloral hydrate is also an inhibitor of protein synthesis. This inhibition is unlikely to be a result of either of the disruption of cell division or of interference with the function of microtubules. The ability of chloral hydrate to inhibit cell division may result from its ability to inhibit protein synthesis.