Aromatic sulphonamides of aziridine-2-carboxylic acid derivatives as novel PDIA1 and PDIA3 inhibitors

In this study, we report a series of newly synthesised sulphonamides of aziridine-2-carboxylic acid (Az-COOH) ester and amide analogues as potent protein disulphide isomerase (PDI, EC 5.3.4.1) inhibitors. The inhibitory activity on PDI was determined against recombinant human PDIA1 and PDIA3 proteins using an insulin reduction assay. These compounds in low micromolar to low nanomolar concentrations showed the effective in vitro inhibitory properties of PDIA1 with weaker effects on PDIA3. Complexes of ¹⁵N- and ¹⁵N,¹³C- uniformly labelled recombinant human PDIA1a with two PDIA1 inhibitors were produced and investigated by a protein nuclear magnetic resonance (NMR) spectroscopy. It was found that both C53 and C56 of the PDIA1 enzyme were involved in covalent binding. Finally, in a range of pharmacological studies, we demonstrated that investigated compounds displayed anti-cancer and anti-thrombotic activity. These findings demonstrate that sulphonamides of Az-COOH derivatives are promising candidates for the development of novel anti-cancer and anti-thrombotic agents.

Exploring Aspartic Protease Inhibitor Binding to Design-Selective Antimalarials

Selectivity is a major issue in the development of drugs targeting pathogen aspartic proteases. Here, we explore the selectivity-determining factors by studying specifically designed malaria aspartic protease (plasmepsin) open-flap inhibitors. Metadynamics simulations are used to uncover the complex binding/unbinding pathways of these inhibitors and describe the critical transition states in atomistic resolution. The simulation results are compared with experimentally determined enzymatic activities. Our findings demonstrate that plasmepsin inhibitor selectivity can be achieved by targeting the flap loop with hydrophobic substituents that enable ligand binding under the flap loop, as such a behavior is not observed for several other aspartic proteases. The ability to estimate the selectivity of compounds before they are synthesized is of considerable importance in drug design; therefore, we expect that our approach will be useful in selective inhibitor designs against not only aspartic proteases but also other enzyme classes.

Rod-through-plate fixation of canine diaphyseal fractures

Efficacy of the rod-through-plate fixation for fracture repair was evaluated in six clinical cases of canine long bone fractures. This fixation incorporates principles of intramedullary and extramedullary osteosynthesis for transverse and short oblique fractures of long tubular bones. The plate-through-rod device is comprised of one pair of curved rods, a connecting plate and two bone screws. The connecting plate has both a hole and a channel on each end. Curved rods have a long curved part and a straight part with a hole in it for screw fixation. All components are made up of medical stainless steel. Clinical and radiographical examinations were performed from week seven to18 months after the operation. Functional abnormalities were not observed at this period in five patients and all fractures were healed. In one patient screw stripping in the proximal fragment of the femur was detected radiologically and minimal implant dislocation was noted at seven weeks after the initial repair. The rod-through-plate fixation method gives strong fixation of bone fragments with minimal traumatization of soft tissue during the operation. The design of the rod-through-plate is intended to reduce pressure of the plate on the cortex in the area of the fracture, whereas the dynamic fixation provided by the intramedullary rods may allow micromotion, thus stimulating callus formation and avoiding implant- induced osteoporosis. Clinical relevance: The rod-through-plate fixator has a simple construction and its use expands the treatment possibilities for diaphyseal fractures of long bones.

Production of recombinant anthrax toxin receptor (ATR/CMG2) fused with human Fc in planta

Mass vaccination against anthrax with existing vaccines is costly and unsafe due to potential side effects. For post-infection treatment, passive immunotherapy measures are currently available, most based on anthrax protective antigen (PA)-specific therapeutic antibodies. Efficient against wild-type strains, these treatment(s) might fail to protect against infections caused by genetically engineered Bacillus anthracis strains. A recent discovery revealed that the von Willebrand factor A (VWA) domain of human capillary morphogenesis protein 2 (CMG2) is an exceptionally effective anthrax toxin receptor (ATR) proficient in helping to resolve this issue. Here we describe in planta production of chimeric recombinant protein (immunoadhesin) comprised of functional ATR domain fused with the human immunoglobulin Fc fragment (pATR-Fc). The fusion design allowed us to obtain pATR-Fc in plant green tissues in a soluble form making it fairly easy to purify by Protein-A chromatography. Standardized pATR-Fc preparations (purity>90%) were shown to efficiently bind anthrax PA as demonstrated by ELISA and Western blot analysis. Recombinant pATR-Fc was also shown to protect J774A1 macrophage cells against the anthrax toxin. This study confirmed that plant-derived pATR-Fc antibody-like protein is a prospective candidate for anthrax immunotherapy.

Rod-through-plate fixation of canine diaphyseal fractures

Efficacy of the rod-through-plate fixation for fracture repair was evaluated in six clinical cases of canine long bone fractures. This fixation incorporates principles of intramedullary and extramedullary osteosynthesis for transverse and short oblique fractures of long tubular bones. The plate-through-rod device is comprised of one pair of curved rods, a connecting plate and two bone screws. The connecting plate has both a hole and a channel on each end. Curved rods have a long curved part and a straight part with a hole in it for screw fixation. All components are made up of medical stainless steel. Clinical and radiographical examinations were performed from week seven to18 months after the operation. Functional abnormalities were not observed at this period in five patients and all fractures were healed. In one patient screw stripping in the proximal fragment of the femur was detected radiologically and minimal implant dislocation was noted at seven weeks after the initial repair. The rod-through-plate fixation method gives strong fixation of bone fragments with minimal traumatization of soft tissue during the operation. The design of the rod-through-plate is intended to reduce pressure of the plate on the cortex in the area of the fracture, whereas the dynamic fixation provided by the intramedullary rods may allow micromotion, thus stimulating callus formation and avoiding implant-induced osteoporosis.

CLINICAL RELEVANCE

The rod-through-plate fixator has a simple construction and its use expands the treatment possibilities for diaphyseal fractures of long bones.

Synthesis and quantitative structure-activity relationship of hydrazones of N-amino-N'-hydroxyguanidine as electron acceptors for xanthine oxidase

A series of new N-hydroxyguanidines were synthesized and tested for electron acceptor activity on bovine milk xanthine oxidase using xanthine as reducing substrate. Manual inspection of the structure-activity data revealed that molecules containing nitro groups ("set A") show a different structure-activity relationship pattern compared to non-nitro compounds ("set B"). Accordingly separate QSAR models were built and validated for the two sets. Substantial differences were found in properties governing acceptor activity for the models, the only common property being sterical access to the imino nitrogen atom of the hydroxyguanidinimines. For set A molecules the presence of a nitro substituent at a certain distance range from the hydroxuguanidino group was most important. In addition, the presence of a nitro group in the ortho position interacting with NH(2) of the hydroxyguanidino group, and the mutual geometry of the phenyl ring, hydroxyguanidine, and imine groups was important for this set. By contrast, for set B molecules the acceptor activity was most influenced by the geometry of methoxy groups and the size and geometry of meta and para substituents of the phenyl ring.

[SPECT and MRT in the diagnosis of myocarditis of mild and moderate severity]

Technetium-99mWBC SPECT and contrast material enhanced MRI were used for the diagnostics of mild myocarditis. The use of labeled leukocytes and paramagnetic contrast agent allow visualizing inflammation of myocardium and assessing the efficacy of treatment. 49 patients aged 14 to 49 years old were studied. Case presentation demonstrates high information and diagnostic value of used methods.

Characterization of a G protein-coupled receptor for nicotinic acid

Nicotinic acid is a lipid-lowering agent widely used to treat hypertriglyceridemia and to elevate low high density lipoprotein levels. However, the underlying mechanisms are poorly understood. In this study, G protein activation by nicotinic acid and derivatives was assessed as stimulation of guanosine 5'-(gamma-[(35)S]-thio)triphosphate ([(35)S]GTPgammaS) binding, and [(3)H]nicotinic acid was used for specific labeling of binding sites. Nicotinic acid (EC(50) approximately 1 microM) stimulated [(35)S]GTPgammaS binding in membranes from rat adipocytes and spleen, but not from other tissues. G protein activation in adipocyte membranes in the presence of maximally activating concentrations of the selective A(1) adenosine receptor agonist 2-chloro-N(6)-cyclopentyladenosine and nicotinic acid was almost additive, indicating that G proteins of mostly distinct pools were activated by these agonists. G protein activation by nicotinic acid and related substances in spleen and adipocytes revealed identical pharmacological profiles. [(3)H]Nicotinic acid specifically detected guanine nucleotide-sensitive binding sites of identical pharmacology in adipocyte and spleen membranes. The site of action of nicotinic acid is distinct from other G protein-coupled receptors. These data indicate that nicotinic acid most probably acts on a specific G protein-coupled receptor.

Characterization of cauliflower mosaic virus (CaMV) resistance in virus-resistant ecotypes of Arabidopsis

Two Arabidopsis ecotypes are resistant to systemic infection by cauliflower mosaic virus (CaMV), a plant para-retrovirus. Arabidopsis ecotype Enkheim-2 (En-2) is highly resistant to CaMV infection while Bla-14 is more weakly resistant. CaMV resistance in En-2 can be largely attributed to the action of a single semidominant gene called cauliflower mosaic virus resistance1 (CAR1), located at a locus on chromosome 1. Resistance in Bla-14 is tightly linked to CAR1 and may be due to a weak allele at the same locus or another gene in a gene cluster. A quantitative polymerase chain reaction assay in conjunction with replication- and movement-incompetent viral mutants was used to determine whether virus replication or movement is affected in the resistant ecotypes. The pattern of accumulation of the wild-type virus in the resistant ecotype, En-2, was similar to that of a movement-incompetent CaMV mutant, suggesting that CAR1 interferes with or fails to support CaMV movement. CaMV-inoculated En-2 plants do not show visible signs of a hypersensitive response. However, indicators of an induced defense response do appear in CaMV-infected En-2 plants, such as the activation of pathogenesis-related protein gene expression and the production of camalexin, an Arabidopsis phytoalexin. Defense responses induced chemically or by mutation in the susceptible ecotypes delayed and reduced the severity of a CaMV infection. These findings suggest that CAR1 acts either in the susceptible ecotype to support virus movement or in the resistant ecotype to signal a defense response.