Incidental processing of biological motion

The successful detection of biological motion can have important consequences for survival. Previous studies have demonstrated the ease and speed with which observers can extract a wide range of information from impoverished dynamic displays in which only an actor's joints are visible. Although it has often been suggested that such biological motion processing can be accomplished relatively automatically, few studies have directly tested this assumption by using behavioral methods. Here we used a flanker paradigm to assess how peripheral "to-be-ignored" walkers affect the processing of a central target walker. Our results suggest that task-irrelevant dynamic figures cannot be ignored and are processed to a level where they influence behavior. These findings provide the first direct evidence that complex dynamic patterns can be processed incidentally, a finding that may have important implications for cognitive, neurophysiological, and computational models of biological motion processing.     

A new high affinity technetium analogue of bombesin containing DTPA as a pharmacokinetic modifier

The bombesin (BN)/gastrin-releasing peptide (GRP) receptor is expressed in high density on the cell surface of a variety of tumors. This makes the receptors accessible as a molecular target for the detection of lesions in which they are expressed. In this study, we describe a high affinity hydrophilic (99m)Tc-labeled BN analogue, [DTPA(1), Lys(3)((99m)Tc-Hx-DADT), Tyr(4)]BN, having diethylenetriaminepentaacetic acid (DTPA), as a build-in pharmacokinetic modifier, to direct its excretion through the urinary system in order to lower abdominal background activity. In vitro binding studies using [(125)I-Tyr(4)]BN (K(d), 0.1 nM) and human prostate cancer PC-3 cell membranes showed that the inhibition constant (K(i)) of [DTPA(1), Lys(3)((99)Tc-Hx-DADT), Tyr(4)]BN was 19.9 +/- 8.0 nM. Biodistribution studies in normal mice showed fast blood clearance (0.15 +/- 0.01% ID/g, 4 h postinjection), low intestinal accumulation (9.16 +/- 2.35% ID/g, 4 h postinjection), and significant uptake in BN/GRP receptor rich tissues such as the pancreas (21.83 +/- 2.88% ID/g, 15 min postinjection). The pancreas/blood, pancreas/muscle, and pancreas/liver ratios were highest at 2 h postinjection at 23, 74, and 8.4, respectively. The uptake in the pancreas could be blocked by BN (11.96 +/- 1.17 vs 0.65 +/- 0.16% ID/g), partially blocked by neuromedin B (11.96 +/- 1.17 vs 6.66 +/- 0.51% ID/g), but not affected by somatostatin (11.96 +/- 1.17 vs 12.91 +/- 2.53% ID/g), indicating that the binding of [DTPA(1), Lys(3)((99m)Tc-Hx-DADT), Tyr(4)]BN to the receptors was specific. Scintigraphic imaging of human PC-3 prostate cancer xenografts in SCID mice gave a high target to nontarget ratio on the image. Thus, [DTPA(1), Lys(3)((99m)Tc-Hx-DADT), Tyr(4)]BN has the potential for imaging BN/GRP receptor-positive lesions.     

Complexation of two proteic insect inhibitors to the active site of chymotrypsin suggests decoupled roles for binding and selectivity

The crystal structures of two homologous inhibitors (PMP-C and PMP-D2v) from the insect Locusta migratoria have been determined in complex with bovine alpha-chymotrypsin at 2.1- and 3.0-A resolution, respectively. PMP-C is a potent bovine alpha-chymotrypsin inhibitor whereas native PMP-D2 is a weak inhibitor of bovine trypsin. One unique mutation at the P1 position converts PMP-D2 into a potent bovine alpha-chymotrypsin inhibitor. The two peptides have a similar overall conformation, which consists of a triple-stranded antiparallel beta-sheet connected by three disulfide bridges, thus defining a novel family of serine protease inhibitors. They have in common the protease interaction site, which is composed of the classical protease binding loop (position P5 to P'4, corresponding to residues 26-34) and of an internal segment (residues 15-18), held together by two disulfide bridges. Structural divergences between the two inhibitors result in an additional interaction site between PMP-D2v (position P10 to P6, residues 21-25) and the residues 172-175 of alpha-chymotrypsin. This unusual interaction may be responsible for species selectivity. A careful comparison of data on bound and free inhibitors (from this study and previous NMR studies, respectively) suggests that complexation to the protease stabilizes the flexible binding loop (from P5 to P'4).     

Mutation of the toxin binding site of PP-1c: comparison with PP-2B

The catalytic cores of PP-1c and PP-2B (calcineurin) are structurally conserved. However, PP-2B is resistant to inhibition by toxins of the okadaic acid and cyclic peptide classes, while PP-1c is potently inhibited. Molecular docking of the structure of microcystin-LR onto the catalytic core of PP-2B identified residues that may be responsible for blocking access of toxins to the catalytic site. Amino acids in PP-1c were substituted with these PP-2B residues to investigate their contribution to PP-2B toxin resistance. Mutants of PP-1c were also produced to test the importance of hydrophobic interactions to toxin binding. Our results suggest that different classes of toxin inhibitors interact with the same hydrophobic side chains of PP-1c through different mechanisms. Substitution of amino acids in PP-1c with PP-2B residues demonstrated no highly significant changes in toxin inhibition. We hypothesize that an interaction outside the catalytic core causing the L7 loop of PP-2B to block the catalytic site may be responsible for PP-2B resistance to toxins.     

Ezrin function is required for ROCK-mediated fibroblast transformation by the Net and Dbl oncogenes

The small G protein RhoA and its GDP/GTP exchange factors (GEFs) Net and Dbl can transform NIH 3T3 fibroblasts, dependent on the activity of the RhoA effector kinase ROCK. We investigated the role of the cytoskeletal linker protein ezrin in this process. RhoA effector loop mutants which can bind ROCK induce relocalization of ezrin to dorsal actin-containing cell surface protrusions, as do Net and Dbl. Both processes are inhibited by the ROCK inhibitor Y27632, which also inhibits association of ezrin with the cytoskeleton, and phosphorylation of T567, conserved between ezrin and its relatives radixin and moesin. ROCK can phosphorylate the ezrin C-terminus in vitro. The ezrin mutant T567A cannot be relocalized by activated RhoA, Net or Dbl or by ROCK itself, and also inhibits RhoA-mediated contractility and focal adhesion formation. Moreover, ezrin T567A, but not wild-type ezrin, restores contact inhibition to Net- and Dbl-transformed cells, and inhibits the activity of Net and Ras in focus formation assays. These results implicate ROCK-mediated ezrin C-terminal phosphorylation in transformation by RhoGEFs.     

The oxidized phospholipid PazePC modulates interactions between Bax and mitochondrial membranes

Activation of the pro-apoptotic protein Bax under intracellular oxidative stress is closely related to its association with the mitochondrial outer membrane (MOM) system, ultimately resulting in cell death. The precise mechanism by which this activation and the subsequent structural changes in the protein occur is currently unknown. In addition to triggering the onset of apoptosis, oxidative stress generates oxidized lipids whose impact on mitochondrial membrane integrity and the activity of membrane-associated Bax is unclear. We therefore devised a model system that mimics oxidative stress conditions by incorporating oxidized phospholipids (OxPls) into mitochondria-like liposomes, and studied the OxPls' impact on Bax-membrane interactions. Differential scanning calorimetry (DSC) was used to study membrane organization and protein stability, while conformational changes in the protein upon contact with lipid vesicles were monitored using far-UV circular dichroism (CD) spectroscopy. The thermograms for liposomes containing the OxPl 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC) differed dramatically from those for unmodified liposomes. Moreover, Bax exhibited enhanced thermal stability in the presence of the modified liposomes, indicating that it interacted strongly with PazePC-containing membranes. The presence of PazePC also increased the α-helical character of Bax compared to the protein alone or with PazePC-free vesicles, at 10°C, 20°C, and 37°C. Presumably, the presence of PazePC-like OxPls a) increases the population of membrane-associated Bax and b) facilitates the protein's insertion into the membrane by distorting the bilayer's organization, as seen by solid-state high-resolution (1)H and (31)P magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy.     

Whole-exome sequencing identifies mutations in GPR179 leading to autosomal-recessive complete congenital stationary night blindness

Congenital stationary night blindness (CSNB) is a heterogeneous retinal disorder characterized by visual impairment under low light conditions. This disorder is due to a signal transmission defect from rod photoreceptors to adjacent bipolar cells in the retina. Two forms can be distinguished clinically, complete CSNB (cCSNB) or incomplete CSNB; the two forms are distinguished on the basis of the affected signaling pathway. Mutations in NYX, GRM6, and TRPM1, expressed in the outer plexiform layer (OPL) lead to disruption of the ON-bipolar cell response and have been seen in patients with cCSNB. Whole-exome sequencing in cCSNB patients lacking mutations in the known genes led to the identification of a homozygous missense mutation (c.1807C>T [p.His603Tyr]) in one consanguineous autosomal-recessive cCSNB family and a homozygous frameshift mutation in GPR179 (c.278delC [p.Pro93Glnfs^∗57]) in a simplex male cCSNB patient. Additional screening with Sanger sequencing of 40 patients identified three other cCSNB patients harboring additional allelic mutations in GPR179. Although, immunhistological studies revealed Gpr179 in the OPL in wild-type mouse retina, Gpr179 did not colocalize with specific ON-bipolar markers. Interestingly, Gpr179 was highly concentrated in horizontal cells and Müller cell endfeet. The involvement of these cells in cCSNB and the specific function of GPR179 remain to be elucidated.     

A prospective cohort study of stroke characteristics,care, and mortality in a hospital stroke registry in Vietnam

Background

As low and middle-income countries such as Vietnam experience the health transition from infectious to chronic diseases, the morbidity and mortality from stroke will rise. In line with the recommendation of the Institute of Medicine’s report on “Promoting Cardiovascular Health in the Developing World” to “improve local data”, we sought to investigate patient characteristics and clinical predictors of mortality among stroke inpatients at Da Nang Hospital in Vietnam.

Methods

A stroke registry was developed and implemented at Da Nang Hospital utilizing the World Health Organization’s Stroke STEPS instrument for data collection.

Results

754 patients were hospitalized for stroke from March 2010 through February 2011 and admitted to either the intensive care unit or cardiology ward. Mean age was 65 years, and 39% were female. Nearly 50% of strokes were hemorrhagic. At 28-day follow-up, 51.0% of patients with hemorrhagic stroke died whereas 20.3% of patients with ischemic stroke died. A number of factors were independently associated with 28-day mortality; the two strongest independent predictors were depressed level of consciousness on presentation and hemorrhagic stroke type. While virtually all patients completed a CT during the admission, evidence-based processes of care such as anti-thrombotic therapy and carotid ultrasound for ischemic stroke patients were underutilized.

Conclusions

This cohort study highlights the high mortality due in part to the large proportion of hemorrhagic strokes in Vietnam. Lack of hypertension awareness and standards of care exacerbated clinical outcomes. Numerous opportunities for simple, inexpensive interventions to improve outcomes or reduce recurrent stroke have been identified.

     

Effectiveness of community-based comprehensive healthy lifestyle promotion on cardiovascular disease risk factors in a rural Vietnamese population: a quasi-experimental study

ABSTRACT: BACKGROUND: Health promotion is a key component for primary prevention of cardiovascular disease (CVD). This study evaluated the impact of healthy lifestyle promotion campaigns on CVD risk factors (CVDRF) in the general population in the context of a community-based programme on hypertension management. METHODS: A quasi-experimental intervention study was carried out in two rural communes of Vietnam from 2006 to 2009. In the intervention commune, a hypertensive-targeted management programme integrated with a community-targeted health promotion was initiated, while no new programme, apart from conventional healthcare services, was provided in the reference commune. Health promotion campaigns focused on smoking cessation, reducing alcohol consumption, encouraging physical activity and reducing salty diets. Repeated cross-sectional surveys in local adult population aged 25 years and over were undertaken to assess changes in blood pressure (BP) and behavioural CVDRFs (smoking, alcohol consumption, physical inactivity and salty diet) in both communes before and after the 3-year intervention. RESULTS: Overall 4,650 adults above 25 years old were surveyed, in four randomly independent samples covering both communes at baseline and after the 3-year intervention. Although physical inactivity and obesity increased over time in the intervention commune, there was a significant reduction in systolic and diastolic BP (3.3 and 4.7 mmHg in women versus 3.0 and 4.6 mmHg in men respectively) in the general population at the intervention commune. Health promotion reduced levels of salty diets but had insignificant impact on the prevalence of daily smoking or heavy alcohol consumption. CONCLUSION: Community-targeted healthy lifestyle promotion can significantly improve some CVDRFs in the general population in a rural area over a relatively short time span. Limited effects on a context-bound CVDRF like smoking suggested that higher intensity of intervention, a supportive environment or a gender approach are required to maximize the effectiveness and maintain the sustainability of the health intervention.     

Tomophagus cattienensis sp. nov., a new Ganodermataceae species from Vietnam: Evidence from morphology and ITS DNA barcodes

The polypore genus Tomophagus was created to segregate one peculiar species, Ganoderma colossum, from the genus Ganoderma. Recent molecular studies have established the validity of this monotypic genus. Here we report the discovery of a second species of Tomophagus, T. cattienensis sp. nov., from Cat Tien National Park in southern Vietnam, a lowland forest that has been designated as a Biosphere Reserve by the United Nations Educational, Scientific and Cultural Organization (UNESCO). Recognition of this new species is based on combined evidence from morphology, cultural characteristics, and ITS rDNA barcodes. The discovery of this new species may have implications for the discovery of novel bioactive compounds for pharmaceutical use and/or for the pulp industry.