Sequencing conjugated polymers by eye.

The solid-state microstructure of a conjugated polymer is the most important parameter determining its properties and performance in (opto)-electronic devices. A huge amount of research has been dedicated to tuning and understanding how the sequence of monomers, the nature and frequency of defects, the exact backbone conformation, and the assembly and crystallinity of conjugated polymers affect their basic photophysics and charge transporting properties. However, because of the lack of reliable high-resolution analytical techniques, all the structure-property relations proposed in the literature are based either on molecular modeling or on indirect experimental data averaged on polydisperse samples.

Polyamine transport is mediated by both endocytic and solute carrier transport mechanisms in the gastrointestinal tract.

The polyamines spermidine and spermine, and their precursor putrescine, are required for cell growth and cellular functions. The high levels of tissue polyamines are implicated in carcinogenesis. The major sources of exogenous polyamines are diet and intestinal luminal bacteria in gastrointestinal (GI) tissues.

Prophylactic embolization of hepatic artery pseudoaneurysm after blunt abdominal trauma in a child.

We describe a 10-year-old boy who developed a pseudoaneurysm in the territory of the left hepatic artery after blunt trauma to the abdomen, which was prophylactically embolized. He was discharged early and was able to return to activities of daily life. In view of the potentially fatal complication of severe hemorrhage from a missed hepatic pseudoaneurysm rupture, recognition and early embolization of a traumatic pseudoaneurysm of hepatic artery are recommended.

Magnetic resonance imaging of the fetal central nervous system in Singapore.

Introduction: Fetal imaging has improved with the development of faster magnetic resonance imaging (MRI) sequences, obviating the requirement for sedation. It is useful in characterising abnormality of the central nervous system in fetuses with abnormal or equivocal antenatal ultrasound findings. We reviewed all cases of fetal brain and spine MRI performed in our institution.

Gene expression analysis of HCT116 colon tumor-derived cells treated with the polyamine analog PG-11047.

Background: The conformationally restricted polyamine analog PG-11047 has significant growth inhibitory activity against prostate and lung cancer cell lines and is currently under evaluation in several clinical trials, both alone and in combination with other drugs, for the treatment of relapsed or refractory cancer. The objective of this study was to identify the molecular signature of genes responsive to PG-11047 treatment and the biochemical effects of this drug in the HCT116 colon cancer cell line.

Materials And Methods: Gene expression analysis was performed using Affymetrix GeneChip human genome U133 Plus 2.

Antigenic and genetic characteristics of swine-origin 2009 A(H1N1) influenza viruses circulating in humans.

Since its identification in April 2009, an A(H1N1) virus containing a unique combination of gene segments from both North American and Eurasian swine lineages has continued to circulate in humans. The lack of similarity between the 2009 A(H1N1) virus and its nearest relatives indicates that its gene segments have been circulating undetected for an extended period. Its low genetic diversity suggests that the introduction into humans was a single event or multiple events of similar viruses.

Combination chemoprevention of intestinal carcinogenesis in a murine model of familial adenomatous polyposis.

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited syndrome in humans. The Apc(Min/+) mouse, which expresses a mutant homolog of the adenomatous polyposis coli gene, is a model of FAP in humans. Treatment with the nonsteroidal anti-inflammatory drugs (NSAIDS) sulindac or celecoxib can suppress polyp development in FAP patients, but responses are generally transient and incomplete.

Identification and characterization of a diamine exporter in colon epithelial cells.

SLC3A2, a member of the solute carrier family, was identified by proteomics methods as a component of a transporter capable of exporting the diamine putrescine in the Chinese hamster ovary (CHO) cells selected for resistance to growth inhibition by high exogenous concentrations of putrescine. Putrescine transport was increased in inverted plasma membrane vesicles prepared from cells resistant to growth inhibition by putrescine compared with transport in inverted vesicles prepared from non-selected cells. Knockdown of SLC3A2 in human cells, using short hairpin RNA, caused an increase in putrescine uptake and a decrease in arginine uptake activity.

Dietary putrescine reduces the intestinal anticarcinogenic activity of sulindac in a murine model of familial adenomatous polyposis.

The nonsteroidal antiinflammatory drug sulindac displays chemopreventive activity in patients with familial adenomatous polyposis (FAP). Sulindac metabolites induce apoptosis in colon tumor cells, in part, by a polyamine-dependent mechanism that can be suppressed with exogenous putrescine. To determine the relevance of this mechanism in animals, we treated Apc(Min/+) mice, a model of human FAP, with sulindac alone or in combination with dietary putrescine.

Pharmacogenomics of the polyamine analog 3,8,13,18-tetraaza-10,11-[(E)-1,2-cyclopropyl]eicosane tetrahydrochloride, CGC-11093, in the colon adenocarcinoma cell line HCT1161.

Polyamine analogs are known to inhibit tumorigenesis at least in part by mimicking some of the regulatory roles of natural polyamines. To begin the identification of those signaling pathways that are involved in differential cellular responses to the synthetic conformationally restricted polyamine analog CGC-11093, we conducted gene expression profiling, proteomic, and genome-wide DNA methylation and histone acetylation analyses of the HCT116 colon adenocarcinoma cell line after treatment with this analog. Gene expression analysis was performed using Affymetrix GeneChip human genome U133 Plus 2.

Role of polyamines in arginine-dependent colon carcinogenesis in Apc(Min) (/+) mice.

We evaluated the role of polyamines in arginine-dependent intestinal tumorigenesis in Apc(Min) (/+) mice. Arginine is a substrate for ornithine synthesis and thus can influence polyamine production. Supplementing the diet with arginine increased intestinal and colonic polyamine levels and colonic carcinogenesis.

The role of NO synthases in arginine-dependent small intestinal and colonic carcinogenesis.

Arginine is catabolized by NOS2 and other nitric oxide synthases to form nitric oxide. We evaluated the roles of dietary arginine and Nos2 in Apc-dependent intestinal tumorigenesis in Min mice with and without a functional Nos2 gene. NOS2 protein was expressed only in intestinal tissues of Apc(Min/+) Nos2+/+ mice.

Fluorescence methods to detect phase boundaries in lipid bilayer mixtures.

Phase diagrams of lipid mixtures can show several different regions of phase coexistence, which include liquid-disordered, liquid-ordered, and gel phases. Some phase regions are small, and some have sharp boundaries. The identity of the phases, their location in composition space, and the nature of the transitions between the phases are important for understanding the behavior of lipid mixtures.

The chemopreventive agent alpha-difluoromethylornithine blocks Ki-ras-dependent tumor formation and specific gene expression in Caco-2 cells.

Mutation of the Kirsten-ras (Ki-ras) proto-oncogene occurs frequently in colorectal cancers. alpha-Difluoromethylornithine (DFMO), an irreversible inhibitor of the polyamine biosynthetic enzyme, ornithine decarboxylase (ODC), inhibits Ki-ras transformation and colon tumorigenesis in carcinogen-treated animal models by mechanisms yet to be elucidated. Caco-2 cells transfected with an activated Ki-ras, but not parental cells, formed tumors in severe combined immunodeficient (SCID) mice.

Severe acute respiratory syndrome (SARS): chest radiographic features in children.

Background: Severe acute respiratory syndrome (SARS) is a recently recognized condition of viral origin associated with substantial morbidity and mortality rates in adults. Little information is available on its radiologic manifestations in children.

Objective: The goal of this study was to characterize the radiographic presentation of children with SARS.

Inhibition of human ornithine decarboxylase activity by enantiomers of difluoromethylornithine.

Racemic difluoromethylornithine (D/L-DFMO) is an inhibitor of ODC (ornithine decarboxylase), the first enzyme in eukaryotic polyamine biosynthesis. D/L-DFMO is an effective anti-parasitic agent and inhibitor of mammalian cell growth and development. Purified human ODC-catalysed ornithine decarboxylation is highly stereospecific.