Nano, micro, and bulk structures in atactic polystyrene-syndiotactic polystyrene blends obtained in situ in presence of the CpTiCl3/SiO2/MAO catalysts (Cp-cyclopentadienyl, MAO-methylaluminoxane).

CpTiCl3/SiO2/MAO (Cp=cyclopentadienyl, MAO - methylaluminoxane) catalysts, where the Al:Ti varies from 20:1 to 500:1, were used in styrene polymerization. Atactic - syndiotactic polystyrene blends (aPS-sPS) were obtained in situ, the morphology of which was investigated by means of scanning electron microscopy. The blends morphology changed according to the kind of catalytic centers: cationic and syndiotactic on the catalyst surface, which create individually atactic or syndiotactic polystyrenes forming specific blends containing nano or micro-forms: when the Al:Ti ranges from 50:1 and to 100:1 in the blends, there occur nano-sPS particles 40-120 nm in size, if the Al:Ti≥300:1, the filament of δ-sPS polymorph, is produced where the filament size ranged from 30 to 10 nm. A decay of this form leads to the formation of spherical sPS forms several hundreds of nm in size. When the Al:Ti ranges 20:1-50:1, blend rods of several dozen micrometers were obtained.

Phytotoxicity and accumulation of anthracene applied to the foliage and sandy substrate in lettuce and radish plants.

The effects of anthracene (ANT) on the growth of two species of vegetable plants (Lactuca sativa L. and Raphanus sativus L.), which play an important role in the human diet, were studied. ANT was applied to the leaves of these plants by foliar deposition, in aerosol form, and to the sandy substrate in which the plants were grown in a greenhouse. It was found that ANT affected plant biomass, especially root biomass, in the case of both foliar and soil application. Under conditions of induced chemical stress, the dry matter of aboveground parts and roots was lower than that in control plants. The rate of photosynthesis decreased by about 20% in both plant species following foliar ANT application. A lower rate of transpiration was also observed in lettuce plants. After the foliar application of ANT, small quantities of the compound were found in the leaves only (0.06-0.18% of the total dose). ANT translocation to other parts of the plants was not observed. This compound underwent rapid chemical changes on the leaf surface under greenhouse conditions. After the application of ANT to a sandy substrate, this compound was detected in the roots and aboveground parts of plants, which indicates that it was transported throughout the plant. In a sandy substrate, the process of ANT decomposition was much slower-60-70% of the administered dose was measured in the soil after the completion of the experiment.

Homo-polymerization of alpha-olefins and co-polymerization of higher alpha-olefins with ethylene in the presence of CpTiCl2(OC6H4X-p)/MAO catalysts (X = CH3, Cl).

Cyclopentadienyl-titanium complexes containing -OC6H4X ligands (X = Cl,CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerization of ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in co-polymerization of ethylene with the alpha-olefins mentioned. The -X substituents exhibit different electron donor-acceptor properties, which is described by Hammett's factor (sigma). The chlorine atom is electron acceptor, while the methyl group is electron donor. These catalysts allow the preparation of polyethylene in a good yield. Propylene in the presence of the catalysts mentioned dimerizes and oligomerizes to trimers and tetramers at 25 degrees C under normal pressure. If the propylene pressure was increased to 7 atmospheres,CpTiCl2(OC6H4CH3)/MAO catalyst at 25 degrees gave mixtures with different contents of propylene dimers, trimers and tetramers. At 70 degrees C we obtained only propylene trimer. Using the catalysts with a -OC(6)H(4)Cl ligand we obtained atactic polymers with M(w) 182,000 g/mol (at 25 degrees C) and 100,000 g/mol (at 70 degrees C). The superior activity of the CpTiCl2(OC6H4Cl)/MAO catalyst used in polymerization of propylene prompted us to check its activity in polymerization of higher alpha-olefins (1-butene, 1-pentene, 1-hexene)and in co-polymerization of these olefins with ethylene. However, when homo-polymerization was carried out in the presence of this catalyst no polymers were obtained. Gas chromatography analysis revealed the presence of dimers. The activity of the CpTiCl2(OC6H4Cl)/MAO catalyst in the co-polymerization of ethylene with higher alpha-olefins is limited by the length of the co-monomer carbon chain. Hence, the highest catalyst activities were observed in co-polymerization of ethylene with propylene (here a lower pressure of the reagents and shorter reaction time were applied to obtain catalytic activity similar to that for other co-monomers). For other co-monomers the activity of the catalyst decreases as follows: propylene >1-butene > 1-pentene >> 1-hexene. In the case of co-polymerization of ethylene with propylene, besides an increase in catalytic activity, an increase in the average molecular weight M(w) of the polymer was observed. Other co- monomers used in this study caused a decrease of molecular weight. A significant increase in molecular weight distribution (M(w)/M(n)) evidences a great variety of polymer chains formed during the reaction.

Synthesis, conformation, and immunosuppressive activity of CLX and its analogues.

The CLX peptide isolated from flax seed has a sequence cyclo-(PPFFILLX), where X is a nonproteinaceous amino acid residue, (2S,4R) 4-amine-N-methylproline. Picur, B.; Lisowski, M.; Siemion, I.Z. Letters Pept Sci 1998, 5, 183-187. The structure of X strongly suggests that this natural amino acid plays a role of the dipeptide moiety with a nonplanar cis peptidomimetic bond. The X residue contains two asymmetrical carbons and thus can appear in four configurations: (2S,4R), (2S,4S), (2R,4S), and (2R,4R). All four diastereoisomers of X were synthesized and characterized as trifluoroacetates of 4-phtalimido-N-methylproline benzylamides. Their full physicochemical characteristics are presented in this article. The synthesis of linear and cyclic analogues of CLX containing all four possible diastereoisomers of X was performed. Additionally, analogues with gamma-aminobutyric acid (GABA) and glycyl-N-methyl-glycine dipeptide [G(Me)G] substituted for X were synthesized. The obtained peptides were purified using HPLC, examined by ESI/MS, and then studied by CD spectroscopy. They were also tested for immunosuppressive activity (PFC in vitro). All of them revealed diverse immunosuppressive activity, however, lower than that of cyclolinopeptide A (CLA) Wieczorek, Z.; Bengtsson, B.; Trojnar, J.; Siemion, I.Z. Peptide Res 1991, 4, 275-283. and cyclosporine A (CsA). Ellis, G.P.; West, G.B. Progress Med Chem 1988, 25, 1-33. The structure of CLX with (2S,4R) 4-amino-N-methylproline was determined by 2-D NMR methods. All amide bonds are in the trans configuration. The cis peptidomimetic group delta-CH(2)-N(CH(3))- is exposed to the outside of the CLX molecule. The peptide contains two loops similar to beta-turns of type IV. Chou, P.Y.; Fasman, G.D. J Mol Biol 1977, 115, 136-715 and has the extended shape flanked by F3 and L7 residues with significant side chain flexibility.

Immunosuppressory activity of the cyclodimeric peptide with RGD-sequences.

Our previous studies showed that the nonapeptide fragment of HLA-DQ of the sequence H-Thr-Pro-Gln-Arg-Gly-Asp-Val-Tyr-Thr-OH, located in the beta164-172 loop, strongly suppresses the humoral and cellular immune responses, while its shorter analogs, H-Arg-Gly-Asp-Val-OH, H-Arg-Gly-Asp-Val-Tyr-OH and H-Gln-Arg-Gly-Asp-Val-Tyr-OH show only a weak stimulatory activity in respect to the humoral immunological response. These fragments contain the Arg-Gly-Asp (RGD) sequence, known for its importance for cellular association phenomena. Based on the crystal structure of HLA-DR1, we also designed and synthesized a cyclic analog H-Cys-Arg-Gly-Asp-Val-Tyr-Cys-OH with restricted conformation, which strongly suppresses the immune response and selectively inhibits the alphavbeta3 integrin, suggesting that the mechanism of the immunosuppressory action of the peptide is associated with inhibition of the integrin. In this paper we present the design and synthesis of the cyclodimeric peptide, Arg-Gly-Asp-Arg-Gly-Asp, which is also known as a selective alphavbeta3 inhibitor. The synthesized peptide strongly suppresses both the humoral and cellular immune response. The results support our hypothesis that the immunomodulatory activity of HLA-DQ fragments may be connected with their interactions with some particular integrins on the cell surface.

Design, synthesis and biological evaluation of a new bridged immunosuppressor.

A bridged peptide with the sequence: H-Thr-Pro-Gln-Arg-Gly-Asp-Val-gamma-Abu-Asn-Asp-Gln-Glu-Glu-Thr-Thr-Gly-Val-Val-Ser-Thr-Pro-Leu-Ile-Arg-Asn-Gly-OH was designed to mimic the discontinuous epitope of the HLA-DQ molecule that might interact with CD4. The bridged peptide revealed distinct suppressory effect in the humoral immune response. This result supports our suggestion that the 164-172 region of the HLA-DQ molecule may enhance its interactions with coreceptors, possibly with CD4.

Differential patterns of cyclosporine A-induced inhibition of humoral and cellular immune responses to sheep erythrocytes in mice.

In this communication we reveal differential inhibitory effects of cyclosporine A (CsA) on generation of the cellular and humoral immune responses to sheep erythrocytes (SRBC) in mice. For the analysis of the regulatory effects of CsA, we analyzed the results of 45 separate experiments performed in recent years where CsA served as a reference drug for our research on various immunoregulatory compounds. The humoral immune response was determined as the number of plaque-forming cells (PFC), and the delayed type hypersensitivity (DTH) was measured by foot pad swelling. We demonstrated that treatment of mice intraperitoneally (ip) with a dose of 100 microg of CsA/mouse, 2 h after immunization resulted in a differential pattern of inhibition of these two types of the immune response depending on the magnitude of the response in a given experiment. In the case of the antibody response (mean number of PFC 2312 median 2200), high PFC numbers were inhibited stronger than low ones; mean values in respective quarters and inhibitory actions were the following: 1,552 (42.3%), 2,049 (52.4%), 2,441 (61.2%) and 3042 (62.5%). In consequence, high, medium and low responses were down-regulated to approximately the same level. Another inhibitory pattern was observed in the DTH model (mean 10.35 units, median 10.8 units), i.e. low DTH responses were suppressed more strongly than high ones. The mean DTH responses and suppression effects in respective quarters were: 7.4 (58.2%), 10.1 (52.7%),11.8 (51.8%) and 13.1 (38.8%). As the result of such CsA action, the DTH response profile was parallel to that of the control response. In summary, the humoral immune response was down-regulated by CsA proportionally to the immune response observed in control mice, while DTH response was inversely proportional. The possible mechanisms of the observed regulatory CsA actions are discussed.

Immunotropic activity of vratizolin (ITCL, Denotivir).

The aim of this study was to evaluate immunotropic properties of vratizolin, a known antiviral drug, in several in vitro and in vivo assays in mouse and human models. We demonstrated that vratizolin exerted strong immunosuppressive actions both in the humoral and cellular immune response to SRBC in mice. The compound affected not only the inductive phase of delayed type hypersensitivity (DTH) but also the effector phase of that response. Vratizolin was effective when given intraperitoneally and orally. The inhibitory action of vratizolin was comparable to that of cyclosporin A (CsA), the reference drug. Vratizolin exhibited also suppressory properties with regard to PHA-induced proliferation of human peripheral blood lymphocytes and that effect exceeded the inhibitory action of CsA. We also showed that vratizolin inhibited to some degree LPS-induced cytokine production in human peripheral blood cultures. The activities of TNF-alpha, IL-1 and IL-6 were inhibited on average by 37, 26 and 35%, respectively. This was in contrast to the effects of CsA which strongly inhibited only IL-1 production. Lastly, we demonstrated that vratizolin markedly inhibited growth of several tumor cell lines. In particular, the compound significantly inhibited growth of mouse leukemia L-1210 and human acute lymphoblastoid leukemia CCRF-CEM cell lines. The presented data suggest that the immunosuppressory action of vratizolin, although similar to that of CsA, is mediated by a different mechanism. The properties of vratizolin, described in this report, indicate that the drug should be further investigated for possible immunosuppressory and antitumor application.

The "two-headed" peptide inhibitors of interleukin-1 action.

Two peptide fragments of IL-1 family proteins, ITGSE and VTKFYF compete with IL-1 for the cellular receptor. We synthesized a series of peptides composed of the sequences ITGSE and VTKFYK bound directly to each other or connected by such linkers as (Gly)(n), L- and D-Pro residues, Glu and Lys residues (with peptide bond formed by main amino and carboxy groups or by side chain groups), and beta-alanine and its homologues. Peptide IX with a gamma-Glu linker was the most potent inhibitor of IL-1 action. It was twice as potent as both of the peptides indicated.

[Retrospective evaluation of the knee function after partial resection of the fat body of the knee]. / Retrospektywna ocena sprawnosci stawu kolanowego po czesciowej resekcji ciala tluszczowego Hoffy.

A series of 64 male patients aged 16-58 years (average 37 years) underwent in the years 1992-1997 a partial resection of the Hoffa pad. The results of this procedure were evaluated. The patients underwent surgery for diagnosed tear of the medial meniscus. At arthrotomy the meniscus was found to be intact and the only visible pathology appeared to be hypertrophic Hoffa pad impinging between the articular surfaces of the joint. The authors attempted to answer the following question: is partial resection of the fat body of the knee a therapeutic procedure or an excuse to justify surgery? The results presented in this paper confirm the therapeutic usefulness of this procedure.

New conformationally restricted analog of the immunosuppressory mini-domain of HLA-DQ and its biological properties.

Our previous studies revealed that the nonapeptide fragment of HLA-DQ located in the beta 164-172 loop of the Thr-Pro-Gln-Arg-Gly-Asp-Val-Tyr-Thr sequence suppresses the immune humoral and cellular responses [30]. Based on the crystal structure of HLA-class II molecules we designed and synthesized a cyclic analog with restricted conformation, cyclo(Suc-Thr-Pro-Gln-Arg-Gly-Asp-Val-Lys)-Thr-OH (Suc = succinyl) by reacting a Lys side chain with a succinylated N-terminus. The cyclization product more potently suppresses the cellular immune response than its linear counterparts and is efficiently cleaved by trypsin. The results indicate that the beta 164-172 loop may serve as a functional epitope on the HLA class II surface for intermolecular binding.

Cyclolinopeptides and their analogs--a new family of peptide immunosuppressants affecting the calcineurin system.

The results of the investigation of immunosuppressive activity of cyclolinopeptide A (CLA--cyclic hydrophobic nonapeptide present in the linseeds) and its analogs are discussed. The results obtained for other natural cyclic peptides showing structural similarities with CLA (antamanide, cycloamanides, hymenistatin, hymenamides) are also reviewed. It results from these investigations that the molecular mechanism of the CLA action is the same as that of cyclosporin A and FK-506 compound, i.e. it consists in formation of the complex with cyclophilin and inhibition--in this form--of the phosphatase activity of calcineurin. The results also suggest that the immunosuppressive activity of these compounds resides in their--Pro-Xxx-Phe- fragment, where Xxx is a hydrophobic (e.g. Leu, Val) or aromatic amino acid residue.

Immunosuppressory mini-regions of HLA-DP and HLA-DR.

Our previous studies showed, that the,TPQRGDVYT, QRGDVYT and RGDVYT fragments, located in the beta164-172 loop of HLA-DQ, strongly suppress the humoral and cellular immune response, while their shorter analogs, RGDV, RGDVY, and QRGDVY, show only weak stimulatory activity in respect to humoral immunological response. The fragments contain the RGDVY sequence that is analogous to thymopentin (pentapeptide RKDVY, an immune system activator) as well as the RGD sequence, known for its importance for cellular association phenomena. Based on the crystal structure of HLA-DR1, we also designed and synthesized a cyclic analog C*RGDVYC* (where C* indicates Cys participating in disulfide bridge) with restricted conformation, which strongly suppresses both humoral and cellular immune response. In the present study we synthesized and tested the immunological properties of the linear and cyclic HLA-DP and HLA-DR counterparts of all the above HLA-DQ fragments. Although the results show that the linear HLA-DP fragments possess moderate immunosuppressory potency, their conformationally restricted analog, C*QGDVYC*C shows a considerable suppression of both humoral and cellular immune response. The nonapeptide fragment of HLA-DR, VPRSGEVYT and particularly its cyclic analog C*SGEVYC*, are strong suppressors of the humoral response.

Length of the peptide chain influences the immunomodulatory activity of peptides related to p53 protein.

We have shown that the thymopoietin-like octapeptides derived from DNA-binding domain of p53 protein and of its mutated forms differ in their immunomodulatory properties. A strong increase of immunostimulative activity was observed for GMNRSPIL (mutated protein) in comparison with GMNRRPIL (wild-type of p53 protein) peptide. Here the elongated sequences of respective protein fragments were synthesized and investigated by plaque forming cells and delayed type hypersensitivity tests. The change of immunomodulatory activity toward immunosuppression was observed: NSSC(Acm)MGGMNRRPILTIITLE (1, wild-type) was inactive in both tests, and the C(Acm)MGGMNRSPILTIITLE (II) and YMC(Acm)NSSC(Acm)MGGMNRSPILTIITLE (III) (mutated p53 protein fragments) peptides produced immunosuppression in plaque forming cells as well as in delayed type hypersensitivity tests.

Hydrolysis of some mRNA 5'-cap analogs catalyzed by the human Fhit protein--and lupin ApppA hydrolases.

Hydrolysis of the following four cap analogs: m7G(5')ppp(5')A, m7G(5')ppp(5')m6A, m7G(5')ppp(5')m2'OG and m7G(5')ppp(5')2'dG catalyzed by homogeneous human Fhit protein and yellow lupin Ap3A hydrolase has been investigated. The hydrolysis products were identified by HPLC analysis and the K(m) and Vmax values calculated based on the data obtained by the fluorimetric method.

Fluorescence studies on association of human translation initiation factor eIF4E with mRNA cap-analogues.

Binding of a long series of mono- and dinucleotide analogues of the 7-methylguanosine containing 5'-mRNA-cap to human protein translation initiation factor eIF4E has been investigated by means of fluorescence. A new methodological approach in gathering and analysis of the fluorescence data provided us with very accurate values of the association equilibrium constant K and normalized, maximal quenching of the protein fluorescence delta Fmax, during titration of eIF4E by various cap-analogues. The results confirm participation of at least two conserved tryptophan residues of eIF4E in interaction with 7-methylguanine, as has been described recently for murine eIF4E, complexed with 7-methyl-GDP in crystal (Marcotrigiano et al., 1997, Cell 89, 951), and for yeast eIF4E, complexed with the same ligand in solution (Matsuo et al., 1997, Nature Struct. Biol. 4, 717). On the other hand binding by eIF4E of unmethylated guanine nucleotides and N2,N2,7-trimethylguanine containing nucleotides differ substantially from the way of binding of the regular mRNA-cap. Influence of the structural features of the cap-analogues, especially the type of the second nucleoside in the dinucleotide caps, on their association with eIF4E and biological activities in in vitro protein translation systems has been discussed in light of the known structures of the eIF4E-7-methyl-GDP complexes in crystal and solution.

Synthesis and immunological activity of new 5-amino-3-methyl 4-amido and 4-ureilene isoxazole derivatives.

5-Amino-3-methylisoxazole-4-carboxylic acid amides and ureilenes have been synthesized from 5-amino-3-methylisoxazole-4-carbonyl azide. The compounds were investigated for potential immunotropic activity in several immunological tests. The most interesting suppressory activities in the humoral and cellular immune response were compared to activities of analogous compounds previously described as immunostimulatory.

Peptides related to FKBP 39-45 loop possess immunostimulative potency.

Taking into account the sequential homology existing between thymopoietin II, the DNA-binding domain of p53 protein and FKBP (FK-506 binding protein), a series of fragments of human and bovine FKBP containing a fragment Ser39-Pro45 were synthesized. In the humoral in vitro test all the peptides act as stimulators. Whereas in the in vivo test peptides derived from bovine FKBP show an immunostimulative and those from human FKBP an immunosuppressive activity. However, after blocking the Asp residue by a Bzl group the peptide V appears to be an immunostimulator. The data obtained suggest that these peptides can influence the immune system by blocking the FKBP receptor.

A fluorescence spectroscopic study on the binding of mRNA 5'-cap-analogs to human translation initiation factor eIF4E: a critical evaluation of the sources of error.

Equilibrium constants for the association of human protein translation initiation factor eIF4E with two mRNA 5'-cap analogs, namely 7-methylguanosine 5'-triphosphate and P1-(7-methylguanosine-5') P3-(guanosine-5') triphosphate, and with guanosine 5'-monophosphate have been redetermined by the fluorescence quenching method taking the inner filter effect of the cap-analog into account. It has been shown that neglecting the latter correction may lead to either underestimation or overestimation of the association constant obtained by applying the Eadie-Hofstee plot: the reasonably firm binding of 7-methylated cap-analogs becomes underestimated, while the weak binding of non-methylated nucleotides becomes overestimated.