A Prospective Study of Magnetic Resonance Imaging Assessment of Post-radiation Changes Following Stereotactic Body Radiation Therapy for Non-small Cell Lung Cancer.

AIMS: Follow-up computed tomography scans after lung stereotactic body radiation therapy (SBRT) are difficult to interpret due to the presence of benign fibrosis, which can make the detection of local recurrence difficult. The objective of this study was to determine the feasibility of a novel thoracic magnetic resonance imaging (MRI) protocol incorporating diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) imaging for the assessment of the treated lung parenchyma after SBRT. MATERIALS AND METHODS: On a prospective trial, post-treatment MR images were acquired in 30 patients treated with SBRT (divided into three different cohorts according to the likelihood of local recurrence as per an expert panel). These images were assessed by an expert thoracic radiologist blind to clinical data, who indicated local recurrence in a dichotomous manner. Local recurrence was confirmed by biopsy or subsequent growth on follow-up computed tomography scans. RESULTS: Thirty patients underwent MRI as part of this study; 27/30 patients were analysable for local recurrence. MRI was conducted at a median of 27.3 months (range 6.5-71 months) from SBRT. No side-effects resulted from either MRI or contrast administration. At a median follow-up time of 45 months after treatment, three local recurrence episodes have occurred. MRI assessment diagnosed seven patients as having a local recurrence, which was later confirmed in three and did not miss any of the true local recurrences. When comparing apparent diffusion coefficient (ADC) values according to local recurrence, the mean ADC value for the local recurrence-free group was 1770 × 10-3 mm/s2 (range 1038-3105 × 10-3 mm/s2) versus 981 × 10-3 mm/s2 (range 926.6-1065 × 10-3 mm/s2) for the local recurrence group (P = 0.0014). CONCLUSIONS: A novel 3.0 T MRI protocol incorporating DWI and DCE was feasible and confirmed the suspicion of local recurrence in patients with highly suspicious computed tomography scans. This imaging tool could potentially aid in selecting patients for salvage treatment after local SBRT failure. Future work should be pursued to validate these findings.

12-lipoxygenase activity plays an important role in PAR4 and GPVI-mediated platelet reactivity.

Following initial platelet activation, arachidonic acid is metabolised by cyclooxygenase-1 and 12-lipoxygenase (12-LOX). While the role of 12-LOX in the platelet is not well defined, recent evidence suggests that it may be important for regulation of platelet activity and is agonist-specific in the manner in which it regulates platelet function. Using small molecule inhibitors selective for 12-LOX and 12-LOX-deficient mice, the role of 12-LOX in regulation of human platelet activation and thrombosis was investigated. Pharmacologically inhibiting 12-LOX resulted in attenuation of platelet aggregation, selective inhibition of dense versus alpha granule secretion, and inhibition of platelet adhesion under flow for PAR4 and collagen. Additionally, 12-LOX-deficient mice showed attenuated integrin activity to PAR4-AP and convulxin compared to wild-type mice. Finally, platelet activation by PARs was shown to be differentially dependent on COX-1 and 12-LOX with PAR1 relying on COX-1 oxidation of arachidonic acid while PAR4 being more dependent on 12-LOX for normal platelet function. These studies demonstrate an important role for 12-LOX in regulating platelet activation and thrombosis. Furthermore, the data presented here provide a basis for potentially targeting 12-LOX as a means to attenuate unwanted platelet activation and clot formation.

Oxadiazole 2-oxides are toxic to the human hookworm, Ancylostoma ceylanicum, however glutathione reductase is not the primary target.

Hookworm disease, characterized by severe anemia and cognitive and growth delays, currently affects an estimated 740 million people worldwide. Despite the prevalence of this parasitic disease, few effective drug therapies are in use today, and the heavy reliance upon benzimidazoles highlights the need for the development of novel chemotherapies. Recent work with the trematode parasite Schistosoma mansoni has identified oxadiazole 2-oxides as effective antischistosomal compounds that function by targeting and inhibiting the antioxidant enzyme, thioredoxin glutathione reductase. In this study, a related enzyme, glutathione reductase, from the human hookworm Ancylostoma ceylanicum was identified and characterized, and its in vitro activity in the presence of the oxadiazole 2-oxides was analyzed. Ex vivo worm killing assays were also conducted to establish the relationship between a given compound's effect upon worm survival and inhibition of recombinant glutathione reductase (rAceGR). Finally, the in vivo anthelminthic efficacy of furoxan (Fx) was assessed in the hamster model of hookworm infection. The predicted amino acid sequence of AceGR contained a prototypical glutathione reductase active site sequence, but no thioredoxin reductase consensus sequences, suggesting that the glutathione and thioredoxin pathways of A. ceylanicum are distinct. Although ten of the forty-two oxadiazole 2-oxides tested inhibited rAceGR activity by at least fifty percent, and fifteen compounds were toxic to parasites ex vivo, little overlap existed between these two results. We therefore suggest that AceGR is not the primary target of the oxadiazole 2-oxides in effecting parasite death. Lastly, oral treatment of A. ceylanicuminfected hamsters with furoxan resulted in significantly improved weight gains and reduced intestinal worm burdens compared to vehicle treated controls, supporting continued development of this molecule as a novel anthelminthic.

Blue-fluorescent antibodies.

The forte of catalytic antibodies has resided in the control of the ground-state reaction coordinate. A principle and method are now described in which antibodies can direct the outcome of photophysical and photochemical events that take place on excited-state potential energy surfaces. The key component is a chemically reactive optical sensor that provides a direct report of the dynamic interplay between protein and ligand at the active site. To illustrate the concept, we used a trans-stilbene hapten to elicit a panel of monoclonal antibodies that displayed a range of fluorescent spectral behavior when bound to a trans-stilbene substrate. Several antibodies yielded a blue fluorescence indicative of an excited-state complex or "exciplex" between trans-stilbene and the antibody. The antibodies controlled the isomerization coordinate of trans-stilbene and dynamically coupled this manifold with an active-site residue. A step was taken toward the use of antibody-based photochemical sensors for diagnostic and clinical applications.

A combined parallel synthesis and screening of macrocyclic lanthanide complexes for the cleavage of phospho di- and triesters and double-stranded DNA.

A parallel synthesis of macrocyclic lanthanide-ligand complexes 4Ln has been developed in conjunction with a parallel screening of these ligands for catalysis of phosphate ester hydrolysis. Complexes 4Ln were screened on a 96-well plate reader for their ability to catalyze the hydrolysis of a variety of phosphate esters efficiently. The hydrolysis of bis(4-nitrophenyl) phosphate (BNPP) 5 and p-nitrophenylethyl phosphate 6 was accelerated by up to 150-fold in the presence of the complex 4cGd. The cleavage of a double-stranded DNA plasmid with this same complex obeyed saturation kinetics following a Michaelian model (K(m) = 7.4 microM, kcat = 4.5 x 10(-3) min-1). Our findings demonstrate how a combination of parallel synthesis and screening can expedite compound access, accelerate catalyst identification, and thereby dramatically increase the speed of finding good ligand-metal combinations.

Reduction of cyclic and acyclic diazene derivates by Azotobacter vinelandii nitrogenase: diazirine and trans-dimethyldiazene.

Nitrogenase reduces N2 to NH3, but the mechanistic details are unclear. Diazene (N2H2), a proposed 2e-/2H+ intermediate on the reduction pathway, is labile under typical enzyme assay conditions, and no firm evidence is available on whether or not it can be reduced by or inhibit nitrogenase. In this paper, we compare the interactions of Azotobacter vinelandii (Av) nitrogenase with two diazene analogues: diazirine, a photolabile diazene containing the azo (-N=N-) group in a strained, three-membered ring, and trans-dimethyldiazene, a diazene containing an unstrained trans-disubstituted N=N bond. Diazirine is reduced by nitrogenase under specific conditions to methane, methylamine, and ammonia in a ratio of ca. 1:2:4-5 with a Km value for all three products similar (0.05-0.09 mM) to that of dinitrogen (0.06-0.12 mM). The Km value of diazirine does not depend on the ratio of nitrogenase Fe protein (Av2) to nitrogenase MoFe protein (Av1) at Av2:Av1 ratios of 0.71 and 14.9. Diazirine potently and competitively inhibits acetylene reduction by Av nitrogenase with Ki = 0.03 mM and is predicted to inhibit H2 evolution completely at pressures >> Km. The experimental Henry's Law constant (1.50 M/atm) determined for trans-dimethyldiazene in H2O shows that it has about 20-fold higher solubility than diazirine in water at 30 degrees C. trans-Dimethyldiazene is reduced by nitrogenase under specific conditions to ammonia, methane and methylamine in a ratio of ca. 1:1:1 with Km values for the three products of 0.51-0.58 M. The product ratio does not change significantly when the component ratio (Av2:Av1 ) is varied over 2.06-13.62. trans-Dimethyldiazene reduction is inhibited noncompetitively by CO and C2H2 with Ki values of ca. 0.0008 and 0.006 atm, respectively. The results are discussed with respect to the stereoelectronic differences between the two azo substrates. A "random-edge" reduction is compared with alternative schemes for the diazirine reduction. For trans-dimethyldiazene, initial C-N cleavage is proposed to yield CH4 and a bound CH3N2H species, which is then reduced to CH3NH2 and NH3.

A new variation of tracheobronchoplastic operation.

A new variation of tracheobronchoplastic operations that we named modified plastic surgery was applied successfully on six patients with lung cancer and one with carcinoid adenoma. Modified plastic surgery consists of adaptive shaping of healthy portions of the bronchi and elimination of parts affected by the pathologic process, which usually required the respective lung resection. Suturing of the fragments reestablished the airways and rendered the formation of postoperative stenoses and anastomoses practically impossible. Indications for this type of operation were decided individually according to the location of the process and the requirements for complete resection in the cases with lung cancer. In many instances this type of operation was the only option for preservation of the organ.