[11C]CHDI-626, a PET Tracer Candidate for Imaging Mutant Huntingtin Aggregates with Reduced Binding to AD Pathological Proteins

The expanded polyglutamine-containing mutant huntingtin (mHTT) protein is implicated in neuronal degeneration of medium spiny neurons in Huntington's disease (HD) for which multiple therapeutic approaches are currently being evaluated to eliminate or reduce mHTT. Development of effective and orthogonal biomarkers will ensure accurate assessment of the safety and efficacy of pharmacologic interventions. We have identified and optimized a class of ligands that bind to oligomerized/aggregated mHTT, which is a hallmark in the HD postmortem brain. These ligands are potentially useful imaging biomarkers for HD therapeutic development in both preclinical and clinical settings. We describe here the optimization of the benzo[4,5]imidazo[1,2-a]pyrimidine series that show selective binding to mHTT aggregates over Aβ- and/or tau-aggregates associated with Alzheimer's disease pathology. Compound [11C]-2 was selected as a clinical candidate based on its high free fraction in the brain, specific binding in the HD mouse model, and rapid brain uptake/washout in nonhuman primate positron emission tomography imaging studies.

Imaging Mutant Huntingtin Aggregates: Development of a Potential PET Ligand

Mutant huntingtin (mHTT) protein carrying the elongated N-terminal polyglutamine (polyQ) tract misfolds and forms protein aggregates characteristic of Huntington's disease (HD) pathology. A high-affinity ligand specific for mHTT aggregates could serve as a positron emission tomography (PET) imaging biomarker for HD therapeutic development and disease progression. To identify such compounds with binding affinity for polyQ aggregates, we embarked on systematic structural activity studies; lead optimization of aggregate-binding affinity, unbound fractions in brain, permeability, and low efflux culminated in the discovery of compound 1, which exhibited target engagement in autoradiography (ARG) studies in brain slices from HD mouse models and postmortem human HD samples. PET imaging studies with ¹¹C-labeled 1 in both HD mice and WT nonhuman primates (NHPs) demonstrated that the right-hand-side labeled ligand [¹¹C]-1R (CHDI-180R) is a suitable PET tracer for imaging of mHTT aggregates. [¹¹C]-1R is now being advanced to human trials as a first-in-class HD PET radiotracer.

Surface nanotopography-induced favorable modulation of bioactivity and osteoconductive potential of anodized 3D printed Ti-6Al-4V alloy mesh structure

The objective of the study described here is to fundamentally elucidate the biological response of 3D printed Ti-6Al-4V alloy mesh structures that were surface modified to introduce titania nanotubes with an average pore size of ∼80 nm via an electrochemical anodization process from the perspective of enhancing bioactivity. The bioactivity of the mesh structures were analyzed through immersion test in simulated body fluid, which confirmed the nucleation and growth of fine globular nanoscale apatite on the nanoporous titania-modified (anodized) mesh structure surface, and agglomerated apatite with fine flakes of apatite crystals on as-fabricated mesh structure surface, that were rich in calcium and phosphorous. The cellular activity of bioactive anodized mesh structure was explored in terms of cell–material interactions involving adhesion, proliferation, synthesis of extracellular and intracellular proteins, differentiation, and mineralization. Cells adhered with a sheet-like morphology on as-fabricated mesh structure, whereas, on anodized mesh structure, numerous filopodia-like cellular extensions interacting with nanotube pores were observed. The formation of a bioactive nanoscale apatite, cell–nanotube interactions as imaged via electron microscopy, higher expression of proteins (actin, vinculin, fibronectin, and alkaline phosphatase (ALP)), and calcium content points toward the determining role of anodized mesh structure in modulating osteoblasts functions. The unique combination of nanoporous bioactive titania and interconnected porous architecture of anodized titanium alloy mesh structure provided a multimodal roughness surface ranging from nano to micro to macroscale, which helps in attaining strong primary and secondary fixation of the implant device along with the pathway for supply of nutrients and oxygen to cells and tissue.

Rare structural variation of synapse and neurotransmission genes in autism

Autism spectrum disorders (ASDs) comprise a constellation of highly heritable neuropsychiatric disorders. Genome-wide studies of autistic individuals have implicated numerous minor risk alleles but few common variants, suggesting a complex genetic model with many contributing loci. To assess commonality of biological function among rare risk alleles, we compared functional knowledge of genes overlapping inherited structural variants in idiopathic ASD subjects relative to healthy controls. In this study we show that biological processes associated with synapse function and neurotransmission are significantly enriched, with replication, in ASD subjects versus controls. Analysis of phenotypes observed for mouse models of copy-variant genes established significant and replicated enrichment of observable phenotypes consistent with ASD behaviors. Most functional terms retained significance after excluding previously reported ASD loci. These results implicate several new variants that involve synaptic function and glutamatergic signaling processes as important contributors of ASD pathophysiology and suggest a sizable pool of additional potential ASD risk loci.

Near-zero anomalous dispersion Ge11.5As24Se64.5 glass nanowires for correlated photon pair generation: design and analysis

We show that highly nonlinear chalcogenide glass nanowire waveguides with near-zero anomalous dispersion should be capable of generating correlated photon-pairs by spontaneous four-wave mixing at frequencies detuned by over 17 THz from the pump where Raman noise is absent. In this region we predict a photon pair correlation of >100, a figure of merit >10 and brightness of ~8×10(8) pairs/s over a bandwidth of >15 THz in nanowires with group velocity dispersion of <5 ps∙km(-1) nm(-1). We present designs for double-clad Ge(11.5)As(24)Se(64.5) glass nanowires with realistic tolerance to fabrication errors that achieve near-zero anomalous dispersion at a 1420 nm pump wavelength. This structure has a fabrication tolerance of 80-170 nm in the waveguide width and utilizes a SiO(2)/Al(2)O(3) layer deposited by atomic layer deposition to compensate the fabrication errors in the film thickness.

Rare structural variants found in attention-deficit hyperactivity disorder are preferentially associated with neurodevelopmental genes

Attention-deficit/hyperactivity disorder (ADHD) is a common and highly heritable disorder, but specific genetic factors underlying risk remain elusive. To assess the role of structural variation in ADHD, we identified 222 inherited copy number variations (CNVs) within 335 ADHD patients and their parents that were not detected in 2026 unrelated healthy individuals. Although no excess CNVs, either deletions or duplications, were found in the ADHD cohort relative to controls, the inherited rare CNV-associated gene set was significantly enriched for genes reported as candidates in studies of autism, schizophrenia and Tourette syndrome, including A2BP1, AUTS2, CNTNAP2 and IMMP2L. The ADHD CNV gene set was also significantly enriched for genes known to be important for psychological and neurological functions, including learning, behavior, synaptic transmission and central nervous system development. Four independent deletions were located within the protein tyrosine phosphatase gene, PTPRD, recently implicated as a candidate gene for restless legs syndrome, which frequently presents with ADHD. A deletion within the glutamate receptor gene, GRM5, was found in an affected parent and all three affected offspring whose ADHD phenotypes closely resembled those of the GRM5 null mouse. Together, these results suggest that rare inherited structural variations play an important role in ADHD development and indicate a set of putative candidate genes for further study in the etiology of ADHD.

Synthesis of N-substituted isoindolinones via a palladium catalysed three-component carbonylation – amination – Michael addition cascade

We herein describe a novel palladium catalysed three-component cascade process involving carbonylation of an aryl iodide to generate an acyl palladium(II) species that is intercepted by a primary aliphatic or aromatic amine, amide, or sulfonamide followed by intramolecular Michael addition to furnish N-substituted isoindolinones in good yield. Overall, the cascade results in the formation of one C—C and two C—N bonds, one ring and one stereocentre.Key words: isoindolinone, palladium, cascade, amidation, sulfonamidation.

Targeting of the yeast Ty5 retrotransposon to silent chromatin is mediated by interactions between integrase and Sir4p

The Ty5 retrotransposons of Saccharomyces cerevisiae integrate preferentially into regions of silent chromatin at the telomeres and silent mating loci (HMR and HML). We define a Ty5-encoded targeting domain that spans 6 amino acid residues near the C terminus of integrase (LXSSXP). The targeting domain establishes silent chromatin when it is tethered to a weakened HMR-E silencer, and it disrupts telomeric silencing when it is overexpressed. As determined by both yeast two-hybrid and in vitro binding assays, the targeting domain interacts with the C terminus of Sir4p, a structural component of silent chromatin. This interaction is abrogated by mutations in the targeting domain that disrupt integration into silent chromatin, suggesting that recognition of Sir4p by the targeting domain is the primary determinant in Ty5 target specificity.

Palladium catalysed 3-component cascade synthesis of bis(2-arylallyl) tertiary amines from aryl iodides, allene and primary amines

A 3-component cascade synthesis of bis(2-arylallyl) tertiary amines from aryl iodide, allene and primary aliphatic amines is described; chiral amines give analogous products with no detectable racemisation; mixtures of two different aryl iodides can be utilised to give the mixed tertiary amines as the sole, or major, product; the reaction is sensitive to stereoelectronic effects which lead to mono(2-arylallyl) secondary amines.

Preferential acetazolamide-induced vasodilation based on vessel size and organ: confirmation of peripheral vasodilation with use of colored microspheres

When carbonic anhydrase activity decreases, the regional blood flow (rBF) in organs increases as hypercapnia develops. However, the effects of acetazolamide (AZ)-induced vasodilation have not been estimated with respect to vessel size and organs. The aim of this study was to determine the diameter of the capillaries in various organs that respond to inhibition of carbonic anhydrase activity by AZ. White rabbits were anesthetized with urethane and ketamine and infused with AZ. While the systolic blood pressure (SBP), pH, hemoglobin concentration, and base excess did not change, the partial pressure of arterial oxygen (PaO2) increased significantly and the partial pressure of arterial carbon dioxide (PaCO2) decreased significantly with AZ. The rBF was calculated by using 3 different sizes (15, 25, and 50 microm) of colored microspheres (CM). The rBF measured with 15 microm CM in the brain, kidneys, and liver increased in response to AZ, and the rBF in these organs was different with the different sizes of CM. However, the rBF calculated by using the different sizes of CM in the stomach and abdominal muscle did not change after the administration of AZ. The AZ-induced vasodilation occurred in all sizes of vessels in the liver, in the small and medium-sized vessels in kidneys, and in the larger capillaries in the brain.

Gene discovery using the maize genome database ZmDB

Zea mays DataBase (ZmDB) is a repository and analysis tool for sequence, expression and phenotype data of the major crop plant maize. The data accessible in ZmDB are mostly generated in a large collaborative project of maize gene discovery, sequencing and phenotypic analysis using a transposon tagging strategy and expressed sequence tag (EST) sequencing. ESTs constitute most of the current content. Database search tools, convenient links to external databases, and novel sequence analysis programs for spliced alignment are provided and together serve as an efficient protocol for gene discovery by sequence inspection. ZmDB can be accessed at http://zmdb. iastate.edu. ZmDB also provides web-based ordering of materials generated in the project, including EST and genomic DNA clones, seeds of mutant plants and microarrays of amplified EST and genomic DNA sequences.

A single amino acid change in the yeast retrotransposon Ty5 abolishes targeting to silent chromatin

Many retrotransposons and retroviruses are thought to select integration sites through interactions with specific chromosomal proteins. In yeast, the Ty5 retrotransposon integrates preferentially with regions bound by silent chromatin, namely the telomeres and the HMR and HML mating loci. A Ty5 mutant (M3) was identified with an approximately 20-fold decrease in targeted integration as measured by a plasmid-based targeting assay. Often chromosomal insertions generated by M3, none were located at the telomeres or silent mating loci. A single amino acid change at the boundary of integrase and reverse transcriptase is responsible for the mutant phenotype. We predict that this mutation lies within a targeting domain that mediates Ty5 target choice by interacting with a component of silent chromatin.

[Clinical analysis of surgical treatment for 86 patients with localized small-cell lung cancer]

To assess the value of surgical treatment followed by adjuvant chemotherapy for localized small-cell lung cancer (SCLC), the results of treatment in 86 SCLC patients since 1990 were reviewed. Of 86 patients, 19 patients received pneumonectomy, 53 lobectomy, 6 wedge resection and 8 segmental resection. Postoperative pathologic staging revealed 24 in stage I, 36 in stage II, and 26 in stage III. Postoperative adjuvant chemotherapy was given in 78 patients. Until the latest follow-up, 28 patients remained alive and 58 patients died. The 5-year survival rate of the 86 patients was 37%. The survival of patients in stage I was better than that of patients in stage II (P = 0.018) and stage III (P = 0.021), but the survival of patients in stage II was not significantly different from that of patients in stage III (P = 0.234). In summary, surgical treatment followed by chemotherapy improves significantly the survival of patients with localized SCLC. TNM staging is of prognostic importance.

CCAAT-box contributions to human thymidine kinase mRNA expression

In order to examine the role of two inverted CCAAT boxes near the start of transcription of the human thymidine kinase (TK) gene, a series of constructs were prepared in which one or both CCAAT boxes were deleted or mutated. These altered promoters (1.2 kb of 5'-flanking sequence) were used to express a TK minigene containing the first two exons and introns followed by the remainder of the cDNA. RNA blots were prepared from stable cell lines of ts13 cells containing these constructs under three conditions: 1) serum deprived cells, 2) serum stimulated cells, and 3) cells that had been stimulated with serum, but were arrested in the G1 phase of the cell cycle by the temperature sensitive mutation carried by these cells. TK mRNA expression from each construct was suppressed by the temperature sensitive block to cell cycle progression. Measurement of protein expression from the various altered TK promoters indicated that both CCAAT boxes contribute to promoter strength. These experiments also suggested that the two CCAAT boxes were not equivalent and that the distal CCAAT could substitute for the proximal CCAAT, but the converse was not true.

Protein that binds to the distal, but not to the proximal, CCAAT of the human thymidine kinase gene promoter

Mobility shift assays were used to examine protein binding to the human TK gene CCAAT boxes. Similar protein binding patterns were observed with probes containing either the proximal or distal CCAAT. However, probes containing both CCAAT boxes in which one of the CCAAT boxes was inactivated by mutation did not demonstrate identical binding patterns. One of the complexes formed with the longer probes was only observed when the distal CCAAT was intact. This species was not formed with probes that only contained an intact proximal CCAAT, and its formation could only be competed by oligonucleotides containing the distal CCAAT motif. This observation reveals the existence of a protein that can bind to the distal, but not to the proximal, CCAAT of the human TK promoter. This protein may account for the previous observation that the two CCAAT motifs are not functionally equivalent. The protein that binds to the distal, but not to the proximal, CCAAT (DTK-CBP) was also present in two human cell lines. Significantly more DTK-CBP was present in nuclear extracts of HepG2 and WI38 cells than in TK-ts13 cells. However, this protein was not observed in three different murine cell lines and one primary culture. Its abundance in some human cell lines suggests it might modulate the expression of human TK mRNA in cells that express this protein.