Synthesis and evaluation of nanoglobular macrocyclic Mn(II) chelate conjugates as non-gadolinium(III) MRI contrast agents

Because of the recent observation of the toxic side effects of Gd(III) based MRI contrast agents in patients with impaired renal function, there is strong interest on developing alternative contrast agents for MRI. In this study, macrocyclic Mn(II) chelates were conjugated to nanoglobular carriers, lysine dendrimers with a silsesquioxane core, to synthesize non-Gd(III) based MRI contrast agents. A generation 3 nanoglobular conjugate of Mn(II)-1,4,7-triaazacyclononane-1,4,7-triacetate-GA amide (G3-NOTA-Mn) was also synthesized and evaluated. The per ion T(1) and T(2) relaxivities of G2, G3, G4 nanoglobular Mn(II)-DOTA monoamide conjugates decreased with increasing generation of the carriers. The T(1) relaxivities of G2, G3, and G4 nanoglobular Mn(II)-DOTA conjugates were 3.3, 2.8, and 2.4 mM(-1) s(-1) per Mn(II) chelate at 3 T, respectively. The T(1) relaxivity of G3-NOTA-Mn was 3.80 mM(-1) s(-1) per Mn(II) chelate at 3 T. The nanoglobular macrocyclic Mn(II) chelate conjugates showed good in vivo stability and were readily excreted via renal filtration. The conjugates resulted in much less nonspecific liver enhancement than MnCl(2) and were effective for contrast-enhanced tumor imaging in nude mice bearing MDA-MB-231 breast tumor xenografts at a dose of 0.03 mmol Mn/kg. The nanoglobular macrocyclic Mn(II) chelate conjugates are promising nongadolinium based MRI contrast agents.     

RICE MORPHOLOGY DETERMINANT encodes the type II formin FH5 and regulates rice morphogenesis

Multicellular organisms contain a large number of formins; however, their physiological roles in plants remain poorly understood. Here, we reveal that formin homology 5 (FH5), a type II formin mutated in rice morphology determinant (rmd), plays a crucial role in determining rice (Oryza sativa) morphology. FH5/RMD encodes a formin-like protein consisting of an N-terminal phosphatase tensin (PTEN)-like domain, an FH1 domain, and an FH2 domain. The rmd mutants display a bending growth pattern in seedlings, are stunted as adult plants, and have aberrant inflorescence (panicle) and seed shape. Cytological analysis showed that rmd mutants have severe cell elongation defects and abnormal microtubule and microfilament arrays. FH5/RMD is ubiquitously expressed in rice tissues, and its protein localization to the chloroplast surface is mediated by the PTEN domain. Biochemical assays demonstrated that recombinant FH5 protein can nucleate actin polymerization from monomeric G-actin or actin/profilin complexes, cap the barbed end of actin filaments, and bundle actin filaments in vitro. Moreover, FH5 can directly bind to and bundle microtubules through its FH2 domain in vitro. Our findings suggest that the rice formin protein FH5 plays a critical role in determining plant morphology by regulating actin dynamics and proper spatial organization of microtubules and microfilaments.     

Nucleic acid binding behaviors and cytotoxic properties of a Ru(II) complex

The interactions of complex [Ru(bpy)(2)(hnip)](2+) (1) {bpy?=?2,2'-bipyridine, hnip?=?2-(2-hydroxy-1-naphthyl)imidazo[4,5-f][1,10]phenanthroline} with calf thymus DNA and yeast tRNA were investigated by UV-vis spectroscopy, fluorescence spectroscopy, viscosity, equilibrium dialysis, and circular dichroism. In addition, the antitumor activities of complex 1 were evaluated with MTT method. These results indicate that the structures of DNA and RNA have significant effects on the binding behaviors of complex 1. Further, complex 1 demonstrates different antitumor activities against selected cancer cell lines in vitro.     

An artifacts removal post-processing for epiphyseal region-of-interest (EROI) localization in automated bone age assessment (BAA)

Background

Guidewire (GW) size and stenosis dimensions are the two major factors affecting the translesional pressure drop. Studying the combined effect of these parameters on the mean pressure drop (Δp) across the stenosis is of high practical importance.

Methods

In this study, time averaged mass and momentum conservation equations are solved analytically to obtain pressure drop-flow, Δp-Q, curves for three different percentage area blockages corresponding to moderate (64%), intermediate (80%), and severe (90%) stenoses. Stenosis is considered to be axisymmetric consisting of three different sections namely converging, throat, and diverging regions. Analytical expressions for pressure drop are obtained for each of these regions separately. Using this approach, effects of lesion length and GW insertion on the mean translesional pressure drop and its component (loss due to momentum change and viscous loss) are analyzed.

Results and Conclusion

It is observed that for a given percent area stenosis (AS), increase in the throat length only increases the viscous loss. However, increase in the severity of stenosis and GW insertion increase both loss due to momentum change and viscous loss. GW insertion has greater contribution to the rise in viscous loss (increase by 2.14 and 2.72 times for 64% and 90% AS, respectively) than loss due to momentum change (1.34% increase for 64% AS and 25% decrease for 90% AS). It also alters the hyperemic pressure drop in moderate (48% increase) to intermediate (30% increase) stenoses significantly. However, in severe stenoses GW insertion has a negligible effect (0.5% increase) on hyperemic translesional pressure drop. It is also observed that pressure drop in a severe stenosis is less sensitive to lesion length variation (4% and 14% increase in Δp for without and with GW, respectively) as compared to intermediate (10% and 30% increase in Δp for without and with GW, respectively) and moderate stenoses (22% and 48% increase in Δp for without and with GW, respectively). Based on the contribution of pressure drop components to the total translesional pressure drop, it is found that viscous losses are dominant in moderate stenoses, while in severe stenoses losses due to momentum changes are significant. It is also shown that this simple analytical solution can provide valuable information regarding interpretation of coronary diagnostic parameters such as fractional flow reserve (FFR).     

The gene expression profile of preclinical autoimmune arthritis and its modulation by a tolerogenic disease-protective antigenic challenge

Introduction  

Autoimmune inflammation is a characteristic feature of rheumatoid arthritis (RA) and other autoimmune diseases. In the natural course of human autoimmune diseases, it is rather difficult to pinpoint the precise timing of the initial event that triggers the cascade of pathogenic events that later culminate into clinically overt disease. Therefore, it is a challenge to examine the early preclinical events in these disorders. Animal models are an invaluable resource in this regard. Furthermore, considering the complex nature of the pathogenic immune events in arthritis, microarray analysis offers a versatile tool to define the dynamic patterns of gene expression during the disease course.     

Antimycobacterial activity: synthesis of novel 3-(substituted phenyl)-6,7-dimethoxy-3a,4-dihydro-3H-indeno[1,2-c]isoxazole analogues

In this study, a series of novel 3-(substituted phenyl)-6,7-dimethoxy-3a,4-dihydro-3H-indeno[1,2-c]isoxazole analogues were synthesized and evaluated for antimycobacterial activity against Mycobacterium tuberculosis (MTB) H(37)Rv and isoniazid resistant M. tuberculosis (INHR-MTB). All the newly synthesized compounds were showing moderate to high inhibitory activities. The compound 6,7-dimethoxy-3-(4-chloro phenyl)-4H-indeno[1,2-c]isoxazole (4b) was found to be the most promising compound, active against MTB H(37)Rv and INHR-MTB with minimum inhibitory concentrations of 0.22 and 0.34 μM.     

Transgenic mice for cre-inducible overexpression of the Cul4A gene

The Cullin 4A(Cul4A) gene is important in cell survival, development, growth, and cell cycle control and is amplified in breast and hepatocellular cancers. Recently, we reported that Cul4A plays an oncogenic role in the pathogenesis of mesothelioma. An important strategy for studying Cul4A in different tissues is targeted overexpression of this gene in vivo. Studies of Cul4A in mice have been restricted to the loss-of-function studies using Cul4A knockout mice; gain-of-function studies of Cul4A using transgenic mice have not been reported. We, therefore, generated a gain-of-function transgenic mouse model that overexpresses Cul4A in a Cre-dependent manner. Before Cre recombination, these mice express LacZ during development in most adult tissues. After Cre-mediated excision of the LacZ reporter, the transfected Cul4A gene is expressed along with a C-terminal Myc-tag in different tissues. In this study, Cre-excision was induced in mouse lungs by inhalation of an adenovirus vector encoding Cre recombinase. This mouse model provides a valuable resource for investigating the significance of Cul4A overexpression in various tissues.     

Fine tuning micellar core-forming block of poly(ethylene glycol)-block-poly(ε-caprolactone) amphiphilic copolymers based on chemical modification for the solubilization and delivery of doxorubicin

This study aimed to optimize poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG-b-PCL)-based amphiphilic block copolymers for achieving a better micellar drug delivery system (DDS) with improved solubilization and delivery of doxorubicin (DOX). First, the Flory-Huggins interaction parameters between DOX and the core-forming segments [i.e., poly(ε-caprolactone) (PCL) and poly[(ε-caprolactone-co-γ-(carbamic acid benzyl ester)-ε-caprolactone] (P(CL-co-CABCL))] was calculated to assess the drug-polymer compatibility. The results indicated a better compatibility between DOX and P(CL-co-CABCL) than that between DOX and PCL, motivating the synthesis of monomethoxy-poly(ethylene glycol)-b-poly[(ε-caprolactone-co-γ-(carbamic acid benzyl ester)-ε-caprolactone] (mPEG-b-P(CL-co-CABCL)) block copolymer. Second, two novel block copolymers of mPEG-b-P(CL-co-CABCL) with different compositions were prepared via ring-opening polymerization of CL and CABCL using mPEG as a macroinitiator and characterized by (1)H NMR, FT-IR, GPC, WAXD, and DSC techniques. It was found that the introduction of CABCL decreased the crystallinity of mPEG-b-PCL copolymer. Micellar formation of the copolymers in aqueous solution was investigated with fluorescence spectroscopy, DLS and TEM. mPEG-b-P(CL-co-CABCL) copolymers had a lower critical micelle concentration (CMC) than mPEG-b-PCL and subsequently led to an improved stability of prepared micelles. Furthermore, both higher loading capacity and slower in vitro release of DOX were observed for micelles of copolymers with increased content of CABCL, attributed to both improved drug-core compatibility and favorable amorphous core structure. Meanwhile, DOX-loaded micelles facilitated better uptake of DOX by HepG2 cells and were mainly retained in the cytosol, whereas free DOX accumulated more in the nuclei. However, possibly because of the slower intracellular release of DOX, DOX-loaded micelles were less potent in inhibiting cell proliferation than free DOX in vitro. Taken together, the introduction of CABCL in the core-forming block of mPEG-b-PCL resulted in micelles with superior properties, which hold great promise for drug delivery applications.     

Synthesis, characterization, and in vivo biodistribution of 125I-labeled Dex-g-PMAGGCONHTyr

Dextran graft poly (N-methacryloylglycylglycine) copolymer-tyrosine conjugates (dextran-g-PMAGGCONHTyr) were synthesized and characterized. Dynamic light scattering (DLS) results indicated that the graft copolymers are soluble in pH 7.4 PBS and 0.9% saline solutions. The graft copolymers were labeled with (125)I, and the labeling stability in 0.9% saline solution was investigated. Pharmacokinetics studies showed a rapid clearance of (125)I-labeled graft copolymers from the blood pool. Biodistribution images confirmed the preferable liver and spleen accumulation within 1 h after injection and rapid clearance from all the organs over time. The graft copolymer with molecular weight of 9.8 kDa was eliminated from the kidney significantly faster than those with higher molecular weight. The effect of the numbers of -COOH groups on the graft copolymers on the biodistribution was also investigated. It was found that the graft copolymers with the average number of -COOH groups per glucopyranose unit (DS(-COOH)) of 0.57 and 0.18 are mainly distributed in liver and spleen at 1 h after injection, whereas the graft copolymer with DS(-COOH) of 0.07 is mainly accumulated in kidney.     

The stability and complexity of antibody responses to the major surface antigen of Plasmodium falciparum are associated with age in a malaria endemic area

Individuals that are exposed to malaria eventually develop immunity to the disease with one possible mechanism being the gradual acquisition of antibodies to the range of parasite variant surface antigens in their local area. Major antibody targets include the large and highly polymorphic Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) family of proteins. Here, we use a protein microarray containing 123 recombinant PfEMP1-DBLα domains (VAR) from Papua New Guinea to seroprofile 38 nonimmune children (<4 years) and 29 hyperimmune adults (≥15 years) from the same local area. The overall magnitude, prevalence and breadth of antibody response to VAR was limited at <2 years and 2-2.9 years, peaked at 3-4 years and decreased for adults compared with the oldest children. An increasing proportion of individuals recognized large numbers of VAR proteins (>20) with age, consistent with the breadth of response stabilizing with age. In addition, the antibody response was limited in uninfected children compared with infected children but was similar in adults irrespective of infection status. Analysis of the variant-specific response confirmed that the antibody signature expands with age and infection. This also revealed that the antibody signatures of the youngest children overlapped substantially, suggesting that they are exposed to the same subset of PfEMP1 variants. VAR proteins were either seroprevalent from early in life, (<3 years), from later in childhood (≥3 years) or rarely recognized. Group 2 VAR proteins (Cys2/MFK-REY+) were serodominant in infants (<1-year-old) and all other sequence subgroups became more seroprevalent with age. The results confirm that the anti-PfEMP1-DBLα antibody responses increase in magnitude and prevalence with age and further demonstrate that they increase in stability and complexity. The protein microarray approach provides a unique platform to rapidly profile variant-specific antibodies to malaria and suggests novel insights into the acquisition of immunity to malaria.