Microwave-assisted three-component domino reaction: Synthesis of indolodiazepinotriazoles

A microwave-assisted three-component protocol involving N-1 alkylation of 2-alkynylindoles with epichlorohydrin, ring opening of the epoxide with sodium azide, and an intramolecular Huisgen azide-internal alkyne 1,3-dipolar cycloaddition domino sequence has been described. The efficacy of the methodology has been demonstrated by treating various 2-alkynylindoles (aromatic/aliphatic) with epichlorohydrin and sodium azide furnishing annulated tetracyclic indolodiazepinotriazoles in satisfactory yields.

Engineering of indole-based tethered biheterocyclic alkaloid meridianin into β-carboline-derived tetracyclic polyheterocycles via amino functionalization/6-endo cationic π-cyclization

A mild, efficient and versatile method has been developed for the construction of a functionalized natural product, meridianin, and its post conversion to pyrimido-β-carboline by cationic π- cyclization. The strategy involves the introduction of an amino group at the C-5 of the pyrimidine ring and utilizing the nucleophilictiy of the C-2 in the indole ring to facilitate cationic π-cyclization.

Synthesis of PECAM-1-specific 64Cu PET imaging agent: evaluation of myocardial infarction caused by ischemia-reperfusion injury in mouse

A PECAM-1 specific PET imaging agent, PECAM-1-Ab-DOTA-(64)Cu, was synthesized by conjugating the anti-mouse PECAM-1 antibody with 2,2',2",2"'-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) and subsequent labeling with (64)Cu. Positron Emission Tomography (PET) was successfully performed in a mouse model of myocardial infarction (MI) induced by an ischemia/reperfusion (I/R) injury, indicating the elevated expression of PECAM-1.

Impact of brain tumor location on morbidity and mortality: a retrospective functional MR imaging study

BACKGROUND AND PURPOSE

fMRI is increasingly used in neurosurgery to preoperatively identify areas of eloquent cortex. Our study evaluated the efficacy of clinical fMRI by analyzing the relationship between the distance from the tumor border to the area of functional activation (LAD) and patient pre- and postoperative morbidity and mortality.

MATERIALS AND METHODS

The study included patients with diagnosis of primary or metastatic brain tumor who underwent preoperative fMRI-based motor mapping (n=74) and/or language mapping (n=77). The impact of LAD and other variables collected from patient records was analyzed with respect to functional deficits in terms of morbidity (paresis and aphasia) and mortality.

RESULTS

Significant relationships were found between motor and language LAD and the existence of either pre- or postoperative motor (P < .001) and language deficits (P=.009). Increasing age was associated with motor and language deficits (P=.02 and P=.04 respectively). Right-handedness was related to language deficits (P=.05). Survival analysis revealed that pre- and postoperative deficits, grade, tumor location, and LAD predicted mortality. Motor deficits increased linearly as the distance from the tumor to the primary sensorimotor cortex decreased. Language deficits increased exponentially as the distance from the tumor to the language areas decreased below 1 cm. Postoperative mortality analysis showed an interaction effect between motor or language LAD and mortality predictors (grade and tumor location, respectively).

CONCLUSIONS

These findings indicate that tumors may affect language and motor function differently depending on tumor LAD. Overall, the data support the use of fMRI as a tool to evaluate patient prognosis and are directly applicable to neurosurgical planning.

Unprecedented Cu-catalyzed coupling of internal 1,3-diynes with azides: one-pot tandem cyclizations involving 1,3-dipolar cycloaddition and carbocyclization furnishing naphthotriazoles

A one-pot protocol for the synthesis of triazole-annulated polyheterocycles via metal-catalyzed coupling of internal 1,4-disubstituted 1,3-diynes and organic azides has been described. The mechanistic rationale for the reaction suggests tandem cyclizations involving copper-catalyzed cycloaddition and 6-endo carbocyclization reactions. The cascade cyclization leads to an increase in molecular complexity to furnish naphtho[1,2-d]triazoles in satisfactory yields. The generality of the method has been demonstrated by using a series of aromatic/aliphatic azides and symmetrical internal 1,3-diynes.

Splay-bend elasticity of a nematic liquid crystal with T-shaped molecules

We measured the splay (K11) and bend (K33) elastic constants in the nematic phase of a liquid crystal with T-shaped molecules. We find that the ratio, K33/K11 ≃1 in the entire nematic range except very close to the nematic to Sm-A (SN) transition. Both K33 and K11 show pretransitional divergence as the SN transition is approached from higher temperature. The ratio, K33/K11 suggests that the length (L) to effective width (D) ratio (i.e., L/D ) is significantly smaller due to the presence of long and flexible lateral group, compared to that of rigid rodlike molecules. It is argued that apart from the extra contribution to the elasticity the long and flexible lateral group also has a significant contribution to the suppression of the splay fluctuations in the onset of smectic short-range fluctuation. The structure of the Sm-A phase is investigated by using small angle x-ray diffraction, and a possible arrangement of the molecules in the Sm-A layer is proposed.

Development of porous HAp and β-TCP scaffolds by starch consolidation with foaming method and drug-chitosan bilayered scaffold based drug delivery system

The inability to maintain high concentrations of antibiotic at the site of infection for an extended period of time along with dead space management is still the driving challenge in treatment of osteomyelitis. Porous bioactive ceramics such as hydroxyapatite (HAp) and beta-tri calcium phosphate (β-TCP) were some of the alternatives to be used as local drug delivery system. However, high porosity and high interconnectivity of pores in the scaffolds play a pivotal role in the drug release and bone resorption. Ceftriaxone is a cephalosporin that has lost its clinical popularity. But has recently been reported to exhibit better bactericidal activity in vitro and reduced probability of resistance development, in combination with sulbactam, a β-lactamase inhibitor. In this article, a novel approach of forming HAp and pure β-TCP based porous scaffolds by applying together starch consolidation with foaming method was used. For the purpose, pure HAp and β-TCP were prepared in the laboratory and after thorough characterization (including XRD, FTIR, particle size distribution, etc.) the powders were used for scaffold fabrication. The ability of these scaffolds to release drugs suitably for osteomyelitis was studied in vitro. The results of the study indicated that HAp exhibited better drug release profile than β-TCP when drug was used alone indicating the high influence of the carrier material. However, this restriction got relaxed when a bilayered scaffold was formed using chitosan along with the drug. SEM studies along with EDAX on the drug-chitosan bilayered scaffold showed closest apposition of this combination to the calcium phosphate surface.

Structural stability and functional analysis of L-asparaginase from Pyrococcus furiosus

We report studies on an L-asparaginase from Pyrococcus furiosus, cloned and expressed in Escherichia coli and purified to homogeneity. Protein stability and enzyme kinetic parameters were determined. The enzyme was found to be thermostable, natively dimeric, and glutaminase-free, with optimum activity at pH 9.0. It showed a K(m) of 12 mM and a substrate inhibition profile above 20 mM L-asparagine. Urea could not induce unfolding and enzyme inactivation; however, with guanidine hydrochloride (GdnCl) a two-state unfolding pattern was observed. Reduced activity and an altered near-UV-CD signal for protein at low GdnCl concentration (1 M) suggested tertiary structural changes at the enzyme active site. A homology three-dimensional model was developed and the structural information was combined with activity and stability data to give functional clues about the asparaginase.

Orthopaedic applications of bone graft & graft substitutes: a review

Treatment of delayed union, malunion, and nonunion is a challenge to the orthopaedic surgeons in veterinary and human fields. Apart from restoration of alignment and stable fixation, in many cases adjunctive measures such as bone-grafting or use of bone-graft substitutes are of paramount importance. Bone-graft materials usually have one or more components: an osteoconductive matrix, which acts as scaffold to new bone growth; osteoinductive proteins, which support mitogenesis of undifferentiated cells; and osteogenic cells, which are capable of forming bone in the appropriate environment. Autologous bone remains the "gold standard" for stimulating bone repair and regeneration, but its availability may be limited and the procedure to harvest the material is associated with complications. Bone-graft substitutes can either substitute autologous bone graft or expand an existing amount of autologous bone graft. We review the currently available bone graft and graft substitutes for the novel therapeutic approaches in clinical setting of orthopaedic surgery.

Orientational order in liquid crystals exhibited by some binary mixtures of rod-like and bent-core molecules

We report measurements of the temperature variations of the optical birefringence in the nematic (N) and partial bilayer SmA (SmA(d)) phases in 4-n-octyloxy 4(')-cyanobiphenyl made of rod-like (R) molecules and five mixtures of this compound with 1,3-phenylene bis[4-(3-methylbenzoyloxy)] 4(')-n-dodecylbiphenyl 4(')-carboxylate, made of bent-core (BC) molecules. The birefringence decreases with the concentration x of the BC molecules but the macroscopic order parameter initially decreases upto 11 mol% of BC molecules and subsequently increases with x. This is attributed to the possible formation of polar clusters of BC molecules. Orientation of BC molecules changes between the N and SmA(d) phases and the birefringence data in the two phases imply that the kink angle of the BC molecules is approximately 90 degrees rather than approximately 110 degrees as obtained from calculations which minimize the energy of the molecule. IR spectroscopic measurements on the mixture with 11 mol% of BC molecules have been used to estimate the molecular order parameter S of the R molecules, and to provide additional support for a relatively small kink angle of BC molecules.

Splay bend elasticity of a bent-core nematic liquid crystal

We measured the splay (K11) and bend (K33) elastic constants in the nematic phase of a bent-core liquid crystal. In the vicinity of the nematic-isotropic transition temperature K33 is proportional to the square of the order parameter. In the nematic range K11 increases monotonically with decreasing temperature, whereas K33 is practically independent of temperature and is smaller than K11 . K33 exhibits a pretransitional slow divergence toward the transition temperature to the smectic phase and becomes slightly larger than K11. The small K33 is explained on the basis of strong coupling of the bent shape of the molecules with the bend distortion.

A novel neutrophil-specific PET imaging agent: cFLFLFK-PEG-64Cu

The synthesis and validation of a new, highly potent (64)Cu-labeled peptide, cFLFLFK-PEG-(64)Cu, that targets the formyl peptide receptor (FPR) on leukocytes is described. The peptide ligand is an antagonist of the FPR, designed not to elicit a chemotactic response resulting in neutropenia. Evidence for the selective binding of this synthesized ligand to neutrophils is provided. PET properties of the compound were evaluated in a mouse model of lung inflammation.

METHODS

The FPR-specific peptide, cinnamoyl-F-(D)L-F-(D)L-FK (cFLFLF), was sequentially conjugated with a bifunctional polyethylene glycol moiety (PEG, 3.4 kD) and a 2,2',2'',2'''-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid (DOTA) through a lysine (K) spacer and finally labeled with (64)Cu-CuCl(2) to form cFLFLFK-PEG-(64)Cu. The binding affinity and stimulation potency of the ligand toward human neutrophils were assessed in vitro. Blood kinetic and organ biodistribution properties of the peptide were studied in the mouse. Ten male C57BL/6 mice were used in this study; 4 control mice and 6 administered Klebsiella pneumonia. PET/CT scans were performed to assess the localization properties of the labeled peptide in lungs 18 h after tracer administration. Lung standardized uptake values (SUVs) were correlated with lung neutrophil activity as measured by myeloperoxidase assays. Immunohistochemistry was performed to confirm that neutrophils constitute the majority of infiltrating leukocytes in lung tissue 24 h after Klebsiella exposure.

RESULTS

In vitro binding assays of the compound cFLFLFK-PEG-(64)Cu to the neutrophil FPR yielded a dissociation constant of 17.7 nM. The functional superoxide stimulation assay exhibited negligible agonist activity of the ligand with respect to neutrophil superoxide production. The pegylated peptide ligand exhibited a blood clearance half-life of 55 +/- 8 min. PET 18 h after tracer administration revealed mean lung SUVs and lung myeloperoxidase activities for Klebsiella-infected mice that were 5- and 6-fold higher, respectively, than those for control mice. Immunohistochemistry staining confirmed that the cellular infiltrate in lungs of Klebsiella-infected mice was almost exclusively neutrophils at the time of imaging.

CONCLUSION

This new radiolabeled peptide targeting the FPR binds to neutrophils in vitro and accumulates at sites of inflammation in vivo. This modified peptide may prove to be a useful tool to probe inflammation or injury.