Multiple sclerosis (MS) is frequently accompanied by visual symptoms including those related to retinal disorders. Since they may be a consequence of an autoimmune reaction, we examined whether sera of patients with diagnosed MS and changes in visual-evoked potentials contain antibodies against retinal antigens (retAgs). Immunoblot analysis revealed that MS sera recognized mainly a 46-kD antigen, a 41-kD antigen, retinal arrestin, to a smaller extent also 70-, 56-, 43-, and 36-kD proteins. Patients whose sera showed the highest reactivity with 41- and 46-kD antigens had deficiencies in visual acuity, visual fields, ophthalmoscopy, and electroretinograms. Our observation suggests that antibodies to these retAgs may play a role in the origin of ophthalmologic impairment in MS.

Objective: Autoantibodies to various neuronal proteins frequently accompany lung cancer and their appearance may precede cancer symptoms. In this study we examined which retinal antigens (RAs) are recognized by sera of patients with lung cancer and whether the occurrence of serum antibodies to particular RAs is characteristic for cancer in comparison with a noncancer lung disease. Methods: Sera of 72 patients with non-small-cell lung cancer (NSCLC), 29 with small-cell lung cancer (SCLC), 27 with sarcoidosis (S), and sera of 32 healthy donors were examined in immunoblotting using retinal extracts and purified RAs as antigens. Results: 69.0% of SCLC, 45.8% of NSCLC, and 44.4% of S sera displayed anti-RAs reactivity. Significantly less (p < 0.05; χ² test) percent of healthy control sera reacted with RAs. Lung cancer sera recognized mainly 46-, 56-, and 36-kD and to a smaller extent also 96-, 72-, 43-, and 26-kD proteins. Most of them were recognized with about 2-fold lower frequencies by S and control sera. Only lung cancer sera contained very high-titer antibodies to 46- and 26-kD RAs, identified as α-enolase and recoverin, respectively. Conclusion: Antibodies to RAs occur more frequently and in higher titers in lung cancer (especially SCLC) than in sarcoidosis or control sera. Although antibodies to retinal α-enolase, recoverin and other RAs are present mainly or exclusively in lung cancer sera, none of them seems to be a specific marker of a particular disease.

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Cancer-associated retinopathy (CAR) is a rare paraneoplastic syndrome usually associated with small-cell lung carcinoma and serum autoantibodies against recovering. We report the breast cancer woman with visual impairments and electrophysiological abnormalities characteristic of CAR. Her serum contained high-titer antibodies against alpha-enolase but not against other retinal proteins. This suggests that anti-enolase antibodies could be responsible for the development of CAR symptoms.

It was demonstrated that phenylmethanesulfonyl fluoride -a very potent inhibitor of penicillin amidase from Escherichia coli -binds covalently to the enzyme in molar ratio 1:1. The chloride, the azide and the Nhydroxysuccinimide ester of phenylmethanesulfonic acid are also very strong inactivators of the amidase. Weaker inhibition was noted with p0ra-substituted phenylmethanesulfonyl chlorides and with phenylethanesulfonyl and alkylsulfonyl chlorides. The inactivated amidase could be reactived by incubation either with 6-aminopenicillanic acid or with proteins from E. coli extract. Benzyl isocyanate is also a potent covalent inhibitor of the amidase but inactivated amidase could be not reactivated in this way. It was demonstrated that representatives of all inactivator types bind to one active site of the amidase. Interdependence between inactivation rate and stability of some sulfonyl inhibitors was observed. No inhibition was noted the amide, the hydrazide and the methyl ester of phenylmethanesulfonic acid. Phenylalkyhulfonyl-Derivate als kovalente Inhibitoren der Penicillin-ArnidaseZusammenfassung: Es wird gezeigt, daß Phenylmethansulfonylfluorid, ein sehr wirksamer Hemmstoff der Penicillin-Amidase aus Escherichia coli, im molaren Verhältnis l: l an das Enzym gebunden wird. Auch das Chlorid, das Azid und der Af-Hydroxysuccinimidester inaktivieren die Amidase weitgehend. Schwächere Hemmwerte wurden mit putra-substituierten Derivaten des Phenylmethansulfonylchlorids, mit Phenylethansulfonylchlorid und Alkylsulfonylchlorid gefunden. Die inaktivierte Amidase läßt sich durch Inkubation entweder mit 6-Aminopenicillansäure oder mit Proteinen aus einem E.-coliExtrakt reaktivieren. Auch Benzylisocyanat ist ein starker kovalenter Inhibitor der Amidase; das so inaktivierte Enzym ist aber nicht wie oben beschrieben reaktivierbar. Vertreter aller Inaktivatortypen werden an ein

Naturally occurring compounds that can act as prosurvival factors and neurite formation stimulants in the conditions of reduced neurotrophins production are important both in neuronal protection and therapy of neurodegenerative disorders. Therefore, the role of proline-rich polypeptide complex (PRP) and its nonapeptide fragment (NP) in the promotion of pheochromocytoma cell line (PC12) survival and neurite outgrowth pathway is presented. It was shown that PRP/NP did not affect the neuronal nitric oxide synthase (nNOS) at the transcriptional and protein level. However, the activity of nNOS and intracellular nitric oxide (NO) concentration was markedly increased after treatment of PC12 cells with peptides. This reaction was inhibited by L-NAME-nNOS inhibitor. It was shown that PRP and NP induce the soluble guanylyl cyclase to release higher amount of cyclic GMP (cGMP), and subsequently, the increased phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) is observed. This effect was abolished by both U0126 (inhibitor of ERK1/2) and also by L-NAME. Reduction of ERK1/2 activity observed in the presence of nNOS inhibitor suggests that its activation is NO-dependent. The presented results shed some light on the mechanism of action of PRP complex. PRP and NP can activate NO/cGMP/ERK1/2 signaling pathway, similarly to nerve growth factor (NGF). The prosurvival action and short fibers formation suggest the role of PRP and NP in neuroprotection and the initiation of neuritogenesis. They can also participate in the amplification of signals controlling the survival and differentiation of neurons effect when the deficit of NGF takes place.

Guanylyl cyclase-activating proteins (GCAPs) and recoverin are retina-specific Ca(2+)-binding proteins involved in phototransduction. We provide here evidence that in spite of structural similarities GCAPs and recoverin differently change their overall hydrophobic properties in response to Ca(2+). Using native bovine GCAP1, GCAP2 and recoverin we show that: i) the Ca(2+)-dependent binding of recoverin to Phenyl-Sepharose is distinct from such interactions of GCAPs; ii) fluorescence intensity of 1-anilinonaphthalene-8-sulfonate (ANS) is markedly higher at high [Ca(2+)](free) (10 microM) than at low [Ca(2+)](free) (10 nM) in the presence of recoverin, while an opposing effect is observed in the presence of GCAPs; iii) fluorescence resonance energy transfer from tryptophane residues to ANS is more efficient at high [Ca(2+)](free) in recoverin and at low [Ca(2+)](free) in GCAP2. Such different changes of hydrophobicity evoked by Ca(2+) appear to be the precondition for possible mechanisms by which GCAPs and recoverin control the activities of their target enzymes.

Serum autoantibodies to visual arrestin, also termed S-antigen, have been shown to accompany several autoimmune-related diseases. However, they were also detected in sera of healthy individuals; there is lack of a sensitive and fast method for evaluation of putative differences between those two groups of antibodies. We show that, using biosensor technology based on surface plasmon resonance (SPR), it was possible to characterize real-time interactions of immune sera with immobilized arrestin. Binding characteristics revealed different interaction kinetics of antiarrestin antibodies present in two distinct rabbit sera and, thus, broadened results of immunoblotting analysis. Therefore, we suggest that SPR-based biosensor technology might be a valuable method for monitoring and evaluation of antiarrestin antibodies in patients' sera.