Search

Background There is insufficient data in the literature regarding the real-life, daily clinical practice evaluation of patients with advanced Parkinson's disease (APD). We are not sure what is the upper limit of dopaminergic medication, especially the levodopa (LD) dosage, and how it is influenced by access and suitability to the various add-on and device-aided therapies (DAT). Objective This retrospective study explored the profile of APD patients that were considered and systematically evaluated regarding the suitability for DAT. Methods We analyzed the data from 311 consecutive patients with APD hospitalized between 2011 and 2017 that 1) described at least 2 hrs/day off periods divided into at least two instances/day (except early morning akinesia), 2) were in stage 3 or above on the Hoehn and Yahr scale, 3) were with or without dyskinesia, and 4) received at least four levodopa doses/day combined with adjuvant therapy. Results Of the 311 patients enrolled initially, 286 patients showed up for the second visit, of which in 125 cases we assessed that DAT would be necessary. Finally, 107 patients were tested in our clinic to confirm the efficacy of LCIG. Patients selected for DAT had significantly longer off periods, more frequent dyskinesia, early morning akinesia, and freezing despite having significantly higher LD doses than those with an improved conservative therapy. Conclusion Patients with APD can have a variety of symptoms, and because symptoms and therapeutical efficacy can be manifested in many different combinations, it is not possible to decide using a single, rigid set of criteria which APD patient is eligible for DAT. Nevertheless, treating physicians should refer APD patients to a specialized movement disorder center when patients with an average daily dose of LD of at least 750-1000 mg and maximal complementary therapies present daily motor complications that significantly reduce the quality of life.

Abstract: Introduction: The motor and non-motor complications of Parkinson’s disease impair the patients’ quality of life and limit therapeutical options. There are no clear criteria for ‘advanced’ Parkinson’s disease or for the optimal moment for invasive therapies. There is little evidence regarding the upper limits of levodopa doses, and how these may be influenced by the availability of device-aided therapies. Aim: To analyze substitution therapy in patients with advanced Parkinson’s disease. Method: In our retrospective study, we analyzed the data from all patients with advanced Parkinson’s disease hospitalized between 1st June 2011 and 31st May 2017, receiving combined levodopa treatment at least 4×/day, reporting a minimum of 2 hours off periods, with or without dyskinesia. We analyzed levodopa therapy for patients who were recommended either device-aided or conservative therapy. Results: Out of 311 patients with advanced Parkinson’s disease, for 125 we proposed device-aided therapies whereas in 42 patients we increased the levodopa dose. The average levodopa doses and the administration rate were higher for the 107 patients tested for levodopa-carbidopa intestinal gel. Disease duration, mean levodopa doses and frequency of dosing were all higher in patients proposed for device-aided therapies versus patients with continued conservative treatment. Conclusion: Our patients were on lower levodopa doses (compared to literature), but the combinations were used more often. Device-aided therapies should be considered in patients with severe motor complications who receive at least 750–1000 mg levodopa daily, divided minimum 5×/day. These patients need to be tested in specialized centers by multidisciplinary teams in order to make the best decision for further action. Orv Hetil. 2019; 160(17): 662–669.

Absztrakt

The crucial role of water in amyloid-β(Aβ) fibril proteins is evaluated in several ways including the water’s thermodynamic and kinetic solvation effects. As regards the water’s character, its hindered-rotation barriers are also considered. The following protein molecules considered here are: the Aβ40 (PDB ID: 2LMN), Aβ42 (PDB ID: 5KK3 and 2NAO) and the double-layered Aβ17−42 fibril. We discuss: (i) extracellular Aβ40 and Aβ42 fibril monomers exhibit an ambivalent propensity to transform into a helical form toward the N-term region and a β-strand-like form near the C-terminal; (ii) interfacial water molecules play a crucial role in protein-protein interactions, as molecular dynamics simulations have shown a significant impact on the protein-protein binding; (iii) it is shown that the spontaneous dimerization process of the Aβ42 fibril protein in water occurs via a two-step nucleation-accommodation mechanism; (iv) MD simulations of the double-layered Aβ17−42 fibril model show that the C↔C interface appears more energetically favorable than the N↔N interface due to large hydrophobic contacts; (v) the water’s role in the HET-s prion and in the Aβ fibrillar aggregates; (vi) it was found that the monomer-oligomer equilibrium spontaneously dissociates into stable monomeric species when they are incubated up to 3 μm for a longer time (>1 week) in a physiological buffer.

The essential involvement of water in most fundamental extra-cellular and intracellular processes of proteins is criticallyreviewed and evaluated in this article. The role of water in protein behavior displays structural ambivalence; it can protectthe disordered peptide-chain by hydration or helps the globular chain-folding, but promotes also the protein aggregation,as well (see: diseases). A variety of amyloid diseases begins as benign protein monomers but develops then into toxic amyloidaggregates of fibrils. Our incomplete knowledge of this process emphasizes the essential need to reveal the principles ofgoverning this oligomerization. To understand the biophysical basis of the simpler in vitro amyloid formation may help todecipher also the in vivo way. Nevertheless, to ignore the central role of the water’s effect among these events means toreceive an uncompleted picture of the true phenomenon. Therefore this review represents a stopgap role, because the mostpublished studies—with a few exceptions—have been neglected the crucial importance of water in the protein research. Thefollowing questions are discussed from the water’s viewpoint: (i) interactions between water and proteins, (ii) proteinhydration/dehydration, (iii) folding of proteins and miniproteins, (iv) peptide/protein oligomerization, and (v) amyloidosis.Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.Keywords: protein hydration; folding; oligomers; amyloid fibrils; miniproteins

During vacuum-packaged frozen storage of fatty goose liver (“foie gras”), a yet unknown, but fully reversible (package opening and thawing), greening was found at a Hungarian processing plant. Laboratory analysis revealed hydrogen sulfide (H2S) and remnant blood in 35 livers. Microbial spoilage was under the limit of detection for H2S-producing strains. In liver homogenates and in thawing exudates, sulfhemoglobin was found and confirmed (acid-alkali reactions), with spectrophotometric analysis. Slaughtered geese are chilled to 2C (24 h) in a non-eviscerated condition to maintain liver shape. With logistic regression, the H2S (most probably from the intestinal tract) was of primary importance in the green color development. In an experimental group (n = 10) dissected after 2 h of body chilling, H2S was absent in the liver. Results indicate that intestinal tract-originated H2S is diffusing the fattened goose liver, leading to a color defect of a delicatesse, without consumer health risks. Practical Applications Hungary leads the world's “foie gras” production, and a rarely occurring production-technology-associated green color defect negatively affects product perception. Fattened, slaughtered geese are chilled to 2C for 24 h in a non-eviscerated form to keep liver intact during dissection. Based on the industrial observations and analytical results, foie gras contains sulfhemoglobin, a non-toxic, green pigment, which is sensitive towards oxidative stimuli. The color defect occurs only in frozen-stored and vacuum-packaged livers. After excluding microbiological spoilage and proving the presence of sulfhemoglobin, we suggest the application of an oxidative packaging technology, e.g., modified atmosphere. Further conditions possibly precluding the formation of sulfhemoglobin may be fresh, warm dissection (immediately after slaughter) or the improvement of the efficacy of bleeding during slaughter. Though the green pigment has no consumer health risk, its full elimination would positively affect the quality of a high-value delicatesse.

The essential role of water in extra- and intracellular coiled coil structures of proteins is critically evaluated, and the different protein types incorporating coiled coil units are overviewed. The following subjects are discussed: i) influence of water on the formation and degradation of the coiled coil domain together with the stability of this conformer type; ii) the water’s paradox iii) design of coiled coil motifs and iv) expert opinion and outlook is presented. The clear and dark sides refer to the positive and negative aspects of the water molecule, as it may enhance or inhibit a given folding event. This duplicity can be symbolized by the Roman ‘Janus-face’ which means that water may facilitate and stimulate coiled coil structure formation, however, it may contribute to the fatal processes of oligomerization and amyloidosis of the very same polypeptide chain.

The freezing effect on peptide coupling in organic solutions of different polarity has been investigated and compared with the results obtained in liquid phase. The model reaction of DCC-activated coupling of Boc-Ala-Phe-OH with H-Ala-OBut has been carried out in dioxane, dimethylsulfoxide and formamide, as well as in mixtures (90%/10%, v/v) of dioxane with acetonitrile, dimethylformamide, dimethylsulfoxide and formamide. The reactions have been traced and evaluated by RP-HPLC analysis. Freezing the reaction mixture resulted in all cases in a significant suppression of the N-dipeptidylurea side-product formation together with a slight decrease of tripeptide epimerization. The coupling yields and the side effects depended on the solvent, with the dioxane and dioxane/acetonitrile mixture produced the best results. The role of freezing and solvent in the improved results is discussed. © 1998 European Peptide Society and John Wiley & Sons, Ltd.

The role of freezing in stereoselection by crystallization of a saturated DL-asparagine solution in preferential condition of L-asparagine, has been investigated. To this end, the L-asparagine excess obtained by crystallization and then kept of different lengths of time at n20 degree C in frozen aqueous solution was analyzed. The samples of the yielded materials were derivatised according to Marfey's method. These derivatives were traced and evaluated by RP-HPLC analysis. The relatively best effects appeared after a one day treatment, where the freezing induced asymmetry amplifications and it increased the L-enantiomer excess from 10 mol percent to 34.9, 35.0 and 35.5 mol percent, respectively. Here we provide the first example of the influence of freezing on chirality amplification by preferential crystallization. Also some speculations are made about the implications of our findings in the prebiotic events of L-amino acids.

A large rate increase of the oxidation of hydroxylamine by iodate has been shown in frozen aqueous solution as compared to the supercooled one. The experiments were conducted under frozen conditions at −5°, −10°, −15°, and −20°C and in liquid solution at 0°, −5°, and −10°C, as well. At given time intervals the progress of the reaction was traced by the pH decrease of the unbuffered samples. The around 500-fold enhanced reaction rate of the frozen samples (at −5° and −10°C) points to an important role of the ice itself beside the increased solute concentration in the compartmentalized heterogeneous system. The contribution of ice to this pH-regulated oxidation is discussed as a consequence of the high mobility and transfer rate of proton on the ice surface. © 1993 John Wiley & Sons, Inc.

The importance of the frozen phase in the formation of cryooscillations of trypsin activity has been shown in experiments conducted at -10 degrees C under frozen and supercooled conditions, respectively. A solution containing trypsin obtained by trypsinogen activation and 0.1 M MnCl2 was distributed in test tubes with or without previous freezing and kept at -10 degrees C and pH 8.4. At given time intervals the frozen and supercooled samples were tested simultaneously for tryptic activity. Although a temporal motion of trypsin activity was produced by the frozen samples, the activity of the supercooled samples began to oscillate only after spontaneous freezing of the solutions. This phenomenon suggests the importance of compartmentalization of the frozen heterogeneous system, which results in an increase in concentration vs a decrease in diffusion rate of the components.

This article is concerned with a study of the role of ice in the synthesis of oligopeptides containing L- or D-enantiomeric excess (ee) from racemic alanine. With this aim, the oligomerization of DL-alanine-N-carboxyanhydride was investigated by keeping this activated derivative in liquid (+22 degrees C) or frozen (-20 degrees C) aqueous solutions for 30 days. The aqueous solution of the peptide mixtures were gel-filtered and the aliquots of the fractions were completely hydrolyzed to alanine monomers. These monomers were then derivatized with 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide (Marfey's reagent) and analyzed by RP-HPLC to reveal the occasional enantiomeric excess of L- or D-Ala. The mass spectrometry of the gel-filtered fractions pointed to open-chain peptide mixtures together with a slight amount of cyclic ones, where the residue numbers ranged between 5-8. Our studies indicated that an enantiomeric excess of L- or D-Ala appeared in some oligopeptide fractions. Their excesses were significantly larger in the frozen than liquid solution. Speculations are made as concerns the implications of our findings in the events of prebiotic chemistry.

The possibility of stereoselection through the DL-alanine-N-carboxyanhydride (NCA-DL-Ala) oligomerization, and the effect of freezing on it have been investigated. To this end, the chirality of peptides obtained by oligomerization for 1 and 3 days, respectively, in liquid (+22 degree celsius) and frozen (-18 degree celsius) dioxane solutions, was analyzed. These water-soluble samples were fractionated by gel filtration, aliquots of the fractions were completely hydrolyzed and then derivatized with Marfey reagent (1-fluoro-2,4-dinitrophenyl-5-L-alanine amide). These derivatives were traced and evaluated by RP-HPLC analysis. The relatively best effects appeared in a given fraction, where after 1 day of oligomerization the L-alanine enantiomeric excess (ee) was 3.8 percent in liquid and 8.6 percent in frozen conditions. After 3 days, however, the ee contents decreased to 2.0 percent and 4.1 percent. The mass spectrometric data of the peptides pointed to the formation of open chain and cyclic peptide mixtures, where the residue numbers of 8-11 and 4-5 dominated. The formation of some chiral peptides from a racemic amino acid suggests the possibility of preferential incorporation of the L-enantiomer into the growing chain, beside the achiral statistical succession of residues. Here we provide the first example of the role of freezing in the increased formation of chirality from racemic amino-acid through oligomerization, together with some speculations about the implications of our model in the events of prebiotic chemistry.

Aperiodic self-similar oscillations of trypsin activity were shown by experiments conducted in the presence of Mn2+ ion at pH 8.2 and -10 degrees C in frozen (cryo-oscillations) and at 0 degrees and 25 degrees C under unstirred conditions, respectively. The solution of trypsin obtained by trypsinogen activation and of 0.1 M MnCl2 was distributed into samples or kept in batches at the experimental temperature and sampled. At given time intervals the samples were tested for tryptic activity. In experiments at -10 degrees C the samples were frozen at the initiating of the series. The irregular shapes of activity curves as well as the trajectory of a next-amplitude plot is discussed as a result of a sensitive coupling between the chemical/conformational and diffusional controls of the enzyme activity in the far-from-equilibrium heterogeneous system. These indicate that the self-similar character of the trypsin activity oscillations can be considered on a phenomenological level.

The effect of the basic group of specific substrates of trypsin on the kinetics of the enzyme was studied. The basic group was substituted by methylamine added to a non-specific substrate. The kinetic constants of tryptic hydrolysis of N-acetyl-l-alanine ethyl ester involving methylamine, at pH 6.3–8.5 were determined. For comparison, the constants of trypsin and α-chymotrypsin were also determined. It can be concluded that methylamine increases the rate of hydrolysis catalyzed by trypsin. The relative increase of the pH-independent limiting value of (kc/Km)max is shown to be fivefold and the pKa decreases by 0.4 unit. The increase of kc is nearly fourfold. The rate constants of the hydrolysis steps catalyzed by trypsin and trypsin · methylamine, respectively, were assayed by means of the nucleophile 1,4-butanediol at pH 6.6. There is a sixfold increase of the original rates caused by methylamine for acylation (k2) and a threefold increase for deacylation (k3) but the substrate dissociation constant (Ks) was almost unchanged. A comparison of the individual rates of the methylamine-activated tryptic hydrolysis of nonspecific substrates with the appropriate data of the trypsin-catalyzed hydrolysis of specific substrates indicates that there is an approximately 1000-fold difference between the rate constants for the acylation step, while in deacylation the difference is insignificant. The methylammonium ion bound to trypsin is supposed to keep the enzyme through the catalysis in a more active conformation than the original one. This indirect effect might bear only a small part of the trypsin-substrate interaction.

Trypsin activity oscillations are shown by the autocatalytic activation of trypsinogen at 0 °C in aqueous solution. The oscillations were observed for 3–4 days and show only slight decrease in enzyme activity. The zymogen has been kept at ice water temperature and pH 8.2 in the presence of Mn2+ ion. The mean periods of around 1.5 hr are about half of those found previously at −10 °C in frozen aqueous solution, while the amplitudes related to the mean activity are about one-fourth of that in the frozen experiments. The phenomenon of oscillation is interpreted in terms of coupling between the inhomogeneities of protein and ion concentrations of the unstirred solution and a Mn 3+ Mn 2+ system, causing synchronous, periodic reduction-oxidation of some cystine bridges in the protein chain. These nonequilibrium conditions, together with synchronous transitions among several conformational states, may produce the observed activity oscillations.

The influence of Mn2+, Fe3+, Co2+, and Zn2+ ions on the extent of trypsinogen activation has been determined for several ion concentrations at pH 7.4 and 36.4 degrees C. For the Mn2+ ion also the autocatalytic rate constants have been detected. The effect of Ca2+ has been reinvestigated for comparison purposes. The apparent dissociation constants of KMn2+ = 0.01 (M) and KCa2+ = 0.02 (M) have been found for the given metal ion-trypsinogen complexes. For Co2+ ion, however, only a slight effect and for Fe3+ and Zn2+ ions no significant effect could be detected on trypsinogen activation. The investigated ions are of empty, open, and completed d subshells of electrons and they are different also in their ionic size. The differences in effects of the ions are discussed on the basis of these factors.

Influence of a homogeneous magnetic field on catalytic rate is proposed as a tool for the investigation of enzyme association. Investigations were initiated with studies of the effect of a 1.4 T homogeneous magnetic field on trypsin activity at 36.5 degrees C and pH 3.3, 5.3, and 7.2, respectively. Periods of exposure were applied up to 2--7 h. No detectable change of activity was observed in any of the exposed systems when they were compared with the identical but unexposed ones.

The effect of Mn2+ and Ca2+ ions on the rate of trypsin autolysis was studied at pH 7.0 and at 34.4-60.2 degrees C. For comparison, the kinetic constants of esterolytic activity of trypsin in the presence of the metal ion were determined at pH 7.4 and at 36 degrees and 40 degrees C. There was no significant difference in the rate of autolysis between Mn2+ and Ca2+ in the temperature range 34-47 degrees C, but at 56.8 degrees and 60.2 degrees autolysis was slightly more rapid in the presence of Mn2+. The Mn2+ or Ca2+ ion bound to trypsin is supposed to control the conformation and thereby the stability and the activity of the enzyme. The indirect effect of Mn2+ and Ca2+ is discussed on a structural basis of the enzyme molecule.

The effect of Mn2+ and Ca2+ on the kinetics of the tryptic activation of bovine trypsinogen was studied at pH 7.3 and 36.5°C. For comparison, the rate constants of autolysis and esterolytic activity of trypsin were also determined. It can be concluded that Mn2+ increases the conversion rate of trypsinogen into trypsin in a 25–40% larger extent than Ca2+. The manganese(II) ion bond to trypsinogen is supposed to keep the N-terminal part of the zymogen in a better conformation for binding at the primary and secondary binding sites of trypsin.