Early atherosclerosis and Chlamydia Pneumoniae Infection in the Coronary Arteries

In non-atheromatous segments of coronary arteries a sequence of preatherosclerotic changes was identified which consisted of medial thickening followed by intimal thickening. More recently, Chlamydia pneumoniae seropositivity was associated with enhanced intima-media thickness of arteries. In the present study the intimal and medial thickness of coronary artery of young adults were measured, and were correlated with the presence of Chlamydia pneumoniae antigens. Proximal and distal segments of the left anterior descending coronaries (LAD) obtained at autopsy from young adults (15-34 years) were studied. The thickness and cellular density of the intima and of the media without clear-cut atherosclerotic changes were measured by image analysis. The hypertrophy index was calculated as the ratio of cell density and the thickness of the respective layer. Atherosclerotic lesions occurring elsewhere in the same coronary were noted and graded by severity. The presence of Chlamydia pneumoniae verified by immunohistochemistry was correlated with the severity of lesions and with the hypertrophy index. In the proximal segments, atherosclerosis of LAD was associated with the widening of both the intima and the media of lesion free-sites. In the distal coronary segments the proportion of the intimal thickening had a significant association with atherosclerosis. Compared to non-infected arteries, Chlamydia pneumoniae infection was associated with higher hypertrophy index in the intima as well as in the media. The rate of Chlamydia pneumoniae positivity increased with the severity of lesions. As a conclusion: in the LAD coronary, the intimal thickening is the main preatherosclerotic change. Chlamydia pneumoniae may favour arterial wall hypertrophy and plays a role in lesion progression

Új kéntartalmú szénhidrát-származékok trypanosoma- ill. amöba-ellenes hatásának vizsgálata: szerkezet-hatás összefüggések = Testing the trypanocidal, amoebicidal activity of novel S-containing sugar derivatives: structure – activity investigations.

A Trypanosoma cruzi protozoa, a Chagas betegség kórokozója, Latin Amerikában évente 12-14 millió ember fertőzéséért felelős. A betegség kezelésére jelenleg alkalmazott szerek hatásossága nem kielégítő, különösen a betegség gyakori, krónikus formája ellen. Kísérleteket folytattunk potenciálisan tripanoszóma-ellenes vegyületek szintézisére; ennek során új, multivalens aromás glikozil-diszulfidokat és néhány diglikozil-diszulfidot állítottunk elő T.cruzi elleni tesztelés céljára. Néhány származék meglepően hatásosnak mutatkozott sejttenyészetből származó tripomasztigoták ellen: az eddig talált legaktívabb származék, az 1,4-bis(ß-D-galaktopiranozil-dithiometilén)-benzol gátlási állandója (IC50) 8.7 ±1.21 µM. Több, hasonló kémiai szerkezettel jellemzett származék is hatásosnak mutatkozott ~ 15 µM-os szinten. A tesztvegyületek citotoxikus hatását konfluens HeLa sejttenyészeteken tanulmányoztuk 18 órás inkubálást követően. Az aktív vegyületek mindegyike csekély citotoxicitást mutatott. További, igen jelentős megfigyelés, hogy az aktív származékok képesek a parazita intracelluláris proliferációját (amasztigota forma) is gátolni, amint ez a T.cruzi-val fertőzött Vero-sejtekből kibocsátott paraziták számlálása bizonyította. Véleményünk szerint ez igen figyelemre méltó eredmény, u.i. a jelenleg alkalmazott T.cruzi elleni szerek (beznidazol, nifurtimox) nem képesek a parazita intracelluláris fázisát gátolni. | Trypanosoma cruzi is the etiologic agent of Chagas disease, an endemic parasitosis in Latin America with 12–14 million people infected. Currently available drugs for treatment of this disease are unsatisfactory, particularly in its prevalent chronic form. In a search for novel chemical structures with potential trypanocidal activity we have synthesized novel aromatic multivalent glycosyl disulfides and some diglycosyl disulfides for testing against T.cruzi. Some of the tested compounds were found remarkably efficient to kill cell culture-derived trypomastigotes; 1,4-bis(ß-D-galactopyranosyl-dithiomethylene) benzene proved to be the most active derivative with an IC50 of 8.7 ±1.21 µM. Other derivatives, of similar chemical structures, were further promising candidates with low IC50 values of ~ 15 µM. The cytotoxic effects of the active and inactive compounds were evaluated after 18 h incubation with confluent HeLa cell cultures. Pleasingly, all of the active trypanocidal agents showed low cytotoxicites. Further, we observed that several of the compounds tested were also able to inhibit intracellular proliferation or parasite differentiation (amastigote form) when the number of parasites released by T.cruzi infected Vero cells was evaluated. These observations, of outstanding interest, show a remarkable effect of these compounds against the intracellular stage of T.cruzi, an activity that is missing in the currently available drugs like beznidazol and nifurtimox

Új, potenciálisan bioaktív szénhidrátok: szintetikus és NMR kutatások = Novel carbohydrates with potential biological activity: synthetic and NMR investigations

Új típusú, 3-kötéses glikozidos hidat (3KGH: -S-S-, -S-C- ) tartalmazó glikomimetikumokat szintetizáltunk. Monoszacharidokat egy központi aromás gyűrűre SS-kötéssel kapcsolva szimmetrikus oligovalens struktúrákat nyertünk. Tioéter (4->6', -S-C-) interglikozidos kiépítésével új típusú pszeudo-diszacharidokat konstruáltunk. A nem hidrolizálható kötés miatt utóbbiak a glikozilhidroláz enzimek potenciális inhibitorai. Új NMR módszereket fejlesztettünk ki a kémiai szerkezet és dinamika hatékonyabb vizsgálatára. Izotópszelektív (15N) telítés alkalmazása az STD NMR kísérletben (15N GS-STD) teljes jelátfedés esetén is lehetővé teszik fehérje-ligandum kölcsönhatások vizsgálatát. Többkötéses heteronukleáris (H,X)-, valamint 13C-13C skaláris csatolási állandók meghatározására új, hatékony 2D NMR módszereket, ill. érzékeny, 1H-detektáláson alapuló kísérleteket (CPMG-HSQMBC, ill. IPAP-DEPT-INADEQUATE és RINEPT-INADEQUATE) javasoltunk. A mért csatolási állandók és egyéb NMR adatok (NOESY/ROESY) felhasználásával elméleti molekulamodellezési módszerekkel határoztuk meg diglikozil-diszulfidok és egyéb szénhidrát-származékok konformációs preferenciáit oldatban. Szilárd fázisban röntgendiffrakciós és kiroptikai (CD) módszereket alkalmaztunk. Az aromás, oligovalens mannozil-diszulfid származékok specifikusan kötődnek a Concanavalin-A lektin-fehérjéhez. A fehérje-ligandum komplexek termodinamikai paramétereit mikrokalorimetriai (ITC), szerkezetüket STD-NMR mérésekkel határoztuk meg. | Novel glycomimetics were synthesized containing three-bond interglycosidic linkages (3BIGL, -S-S-, -S-C-). Glycopyranosyl units were attached to an aromatic scaffold through SS-linkages to obtain symmetric oligovalent structures. Non-glycosidic, 4,6'-thioether (-S-C-) -linked pseudodisaccharides were constructed via highly diastereoselective synthesis; these are potential inhibitors of glycosylhydrolases. Efficient NMR techniques were developed for in-depth studies of molecular structures and dynamics. Extension of the STD NMR experiment with an isotope selective (15N) saturation sequence allows exploration of protein-ligand interactions even in case of complete signal overlap. Novel 2D NMR methods were devised for more accurate measurement of long-range heteronuclear couplings (CPMG-HSQMBC), including sensitive 1H-detection schemes for 13C-13C scalar couplings at natural abundance (DEPT-INADEQUATE, RINEPT-INADEQUATE). Complete sets of experimental coupling constants and NOESY/ROESY data supplemented with molecular modelling allowed determination of conformational preferences of diglycosyl disulfides and other carbohydrate derivatives in solution. X-ray and chiroptical (CD) methods were applied for solid state studies. Aromatic, oligovalent mannosyl disulfides were shown to bind specifically to Concanavalin A, a plant lectin. The thermodynamic parameters and structures of the protein-ligand complexes were determined by microcalorimetry (ITC) and STD-NMR, respectively

Probing pattern and dynamics of disulfide bridges using synthesis and NMR of an ion channel blocker peptide toxin with multiple diselenide bonds

Anuroctoxin (AnTx), a 35-amino-acid scorpion toxin containing four disulfide bridges, is a high affinity blocker of the voltage-gated potassium channel Kv1.3, but also blocks Kv1.2. To improve potential therapeutic use of the toxin, we have designed a double substituted analog, [N17A/F32T]-AnTx, which showed comparable Kv1.3 affinity to the wild-type peptide, but also a 2500-fold increase in the selectivity for Kv1.3 over Kv1.2. In the present study we have achieved the chemical synthesis of a Sec-analog in which all cysteine (Cys) residues have been replaced by selenocysteine (Sec) forming four diselenide bonds. To the best of our knowledge this is the first time to replace, by chemical synthesis, all disulfide bonds with isosteric diselenides in a peptide/protein. Gratifyingly, the key pharmacological properties of the Sec-[N17A/F32T]-AnTx are retained since the peptide is functionally active. We also propose here a combined experimental and theoretical approach including NOE- and Se-77-based NMR supplemented by MD simulations for conformational and dynamic characterization of the Sec-[N17A/F32T]-AnTx. Using this combined approach allowed us to attain unequivocal assignment of all four diselenide bonds and supplemental MD simulations allowed characterization of the conformational dynamics around each disulfide/diselenide bridge

Exploring the Syntheses of Novel Glycomimetics: Carbohydrate Derivatives with Se-S- or Se-Se- Glycosidic Linkages

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Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

Condensed O,N-heterocycles containing tetrahydro-1,4-benzoxazepine and tetrahydroquinoline moieties were prepared by a regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction of a 4-aryl-2-phenyl-1,4-benzoxazepine derivative obtained from flavanone. The relative configuration of products were determined by the correlation of 3JH,H coupling data with the geometry of major conformers accessed by DFT conformational analysis. Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2) or β-amyloid25–35 (Aβ25–35)-induced cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls

Photochemical and Structural Studies on Cyclic Peptide Models

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Probing pattern and dynamics of disulfide bridges using synthesis and NMR of an ion channel blocker peptide toxin with multiple diselenide bonds

Anuroctoxin (AnTx), a 35-amino-acid scorpion toxin contg. four disulfide bridges, is a high affinity blocker of the voltage-gated potassium channel Kv1.3, but also blocks Kv1.2. To improve the potential therapeutic use of the toxin, we have designed a double substituted analog, [N17A/F32T]-AnTx, which showed comparable Kv1.3 affinity to the wild-type peptide, but 2500-fold increase in the selectivity for Kv1.3 over Kv1.2. In the present study we have achieved the chem. synthesis of a Sec-analog in which all cysteine (Cys) residues have been replaced by selenocysteine (Sec) forming four diselenide bonds. To the best of our knowledge this is the first time to replace, by chem. synthesis, all disulfide bonds with isosteric diselenides in a peptide/protein. Gratifyingly, the key pharmacol. properties of the Sec-[N17A/F32T]-AnTx are retained since the peptide is functionally active. We also propose here a combined exptl. and theor. approach including NOE- and 77Se-based NMR supplemented by MD simulations for conformational and dynamic characterization of the Sec-[N17A/F32T]-AnTx. The use of such combined approach allowed us to attain unequivocal assignment of all four diselenide bonds and supplemental MD simulations allowed to characterize the conformational dynamics around each disulfide/diselenide bridge. [on SciFinder(R)

Cryptocapsinepoxide-type Carotenoids from Red Mamey, Pouteria sapota

Three new carotenoids, cryptocapsin-5,6-epoxide, 3ʹ-deoxycapsanthin-5,6-epoxide, and cryptocapsin-5,8-epoxides, have been isolated from the ripe fruits of red mamey (Pouteria sapota). Cryptocapsin-5,6-epoxide was prepared by partial synthesis via epoxidation of cryptocapsin and the (5R,6S)- and (5S,6R)-stereoisomers were identified by HPLC-ECD analysis. Spectroscopic data of the natural (anti) and semisynthetic (syn) derivatives obtained by acid-catalyzed rearrangement of cryptocapsin-5,8-epoxide stereoisomers were compared for structural elucidation. Chiral HPLC separation of natural and semisynthetic samples of cryptocapsin-5,8-epoxides was performed and HPLC-ECD analysis allowed configurational assignment of the separated stereoisomers

Classification of mesic grasslands and their transitions of South Transdanubia (Hungary)

Relevés from meadows and pastures of South Transdanubia (Hungary) are evaluated by clustering and ordination methods. The relevé selection focused on the Arrhenatheretalia order but its transitions towards other types were also included. The groups of relevés are delimited and described according to differential, dominant and constant species. Ecological conditions of the groups were compared using indicator values. Nine groups were distinguished, four of them belonging strictly to the order Arrhenatheretalia. Each alliance of Arrhenatheretalia presented in the study area (Cynosurion, Arrhenatherion) was represented by two groups. Groups from these two alliances are separated along a light gradient, while groups of the same alliance differ in nutrient values. Within Cynosurion, the nutrient-poor group cannot be identified unambiguously as any syntaxa previously known from Hungary. The nutrient-rich Cynosurion meadows are similar to Lolio–Cynosuretum, however, they show a stronger relationship with wet meadows. Within Arrhenatherion, Pastinaco–Arrhenatheretum is recognised as a hay meadow of nutrient-rich soils. The other meadow type is similar to Filipendulo–Arrhenatheretum, thus raising syntaxonomical problems. There are transitional groups towards semi-dry and wet meadows, one dynamic phase and one outlier group among the other five clusters