Differential effects of two types of formative assessment in predicting performance of first-year medical students.

Formative assessments are systematically designed instructional interventions to assess and provide feedback on students' strengths and weaknesses in the course of teaching and learning. Despite their known benefits to student attitudes and learning, medical school curricula have been slow to integrate such assessments into the curriculum. This study investigates how performance on two different modes of formative assessment relate to each other and to performance on summative assessments in an integrated, medical-school environment.

Elucidating the murine brain transcriptional network in a segregating mouse population to identify core functional modules for obesity and diabetes.

Complex biological systems are best modeled as highly modular, fluid systems exhibiting a plasticity that allows them to adapt to a vast array of changing conditions. Here we highlight several novel network-based approaches to elucidate genetic networks underlying complex traits. These integrative genomic approaches combine large-scale genotypic and gene expression results in segregating mouse populations to reconstruct reliable genetic networks underlying complex traits such as disease or drug response.

Genetic and genomic analysis of a fat mass trait with complex inheritance reveals marked sex specificity.

The integration of expression profiling with linkage analysis has increasingly been used to identify genes underlying complex phenotypes. The effects of gender on the regulation of many physiological traits are well documented; however, "genetical genomic" analyses have not yet addressed the degree to which their conclusions are affected by sex. We constructed and densely genotyped a large F2 intercross derived from the inbred mouse strains C57BL/6J and C3H/HeJ on an apolipoprotein E null (ApoE-/-) background.

Integrating genetic and gene expression data to study the metabolic syndrome and diabetes in mice.

Increasingly, the mouse is becoming the standard model for mammalian physiology and disease. It can be genetically analyzed and manipulated with relative ease. Moreover, the endogenous genetic variation that exists among inbred mouse strains can be exploited to identify genetic control of complex physiologic processes involved in diabetes and the metabolic syndrome, among other conditions relevant to human disease.

Stochasticity of manganese superoxide dismutase mRNA expression in breast carcinoma cells by molecular beacon imaging.

Visual and quantitative monitoring of cell-to-cell variation in the expression of manganese superoxide dismutase (MnSOD) mRNA by using novel ratiometric imaging with molecular beacons (MB) reveals a distinct change in patterns following induction of human breast-carcinoma cells with lipopolysaccharide. Interestingly, the pattern of cell-to-cell variation in a cell line stably transfected with a plasmid bearing a cDNA clone of MnSOD and overproducing the enzyme is significantly different from the pattern associated with MnSOD induction. The levels and the patterns of cell-population heterogeneity for beta-actin mRNA expression do not show distinct changes either following induction or in stably transfected cells.

Integrating genotypic and expression data in a segregating mouse population to identify 5-lipoxygenase as a susceptibility gene for obesity and bone traits.

Forward genetic approaches to identify genes involved in complex traits such as common human diseases have met with limited success. Fine mapping of linkage regions and validation of positional candidates are time-consuming and not always successful. Here we detail a hybrid procedure to map loci involved in complex traits that leverages the strengths of forward and reverse genetic approaches.

Simultaneous monitoring of the expression of multiple genes inside of single breast carcinoma cells.

Monitoring gene expression is at the center of research for a wide variety of medical, biological, and biotechnological applications. Currently no method exists for true multiple gene expression monitoring inside of a single living cell that allows for the gene expression profile of the cell to be directly compared with another single living cell. By microinjecting multiple molecular beacons with different fluorophores inside of single breast carcinoma cells and monitoring with advanced fluorescent microscopy, the expression of multiple genes can be simultaneously monitored inside single living cells.

Genomic analysis of metabolic pathway gene expression in mice.

Background: A segregating population of (C57BL/6J x DBA/2J)F2 intercross mice was studied for obesity-related traits and for global gene expression in liver. Quantitative trait locus analyses were applied to the subcutaneous fat-mass trait and all gene-expression data. These data were then used to identify gene sets that are differentially perturbed in lean and obese mice.

Molecular beacons for bioanalytical applications.

Molecular beacons (MBs) are hairpin-shaped oligonucleotides that contain both fluorophore and quencher moieties. They act like switches and are normally in a closed state, when the fluorophore and the quencher are brought together to turn "off" the fluorescence. When prompted to undergo conformational changes that open the hairpin structure, the fluorophore and the quencher are separated, and fluorescence is turned "on.

An integrative genomics approach to infer causal associations between gene expression and disease.

A key goal of biomedical research is to elucidate the complex network of gene interactions underlying complex traits such as common human diseases. Here we detail a multistep procedure for identifying potential key drivers of complex traits that integrates DNA-variation and gene-expression data with other complex trait data in segregating mouse populations. Ordering gene expression traits relative to one another and relative to other complex traits is achieved by systematically testing whether variations in DNA that lead to variations in relative transcript abundances statistically support an independent, causative or reactive function relative to the complex traits under consideration.

Single cell glutamate analysis in Aplysia sensory neurons.

Glutamate is the major excitatory neurotransmitter in the central nervous system. However, techniques and assays available for the determination and detection of glutamate are limited. Here we have applied an effective glutamate assay toward the high-throughput analysis of single neurons.

Cis-acting expression quantitative trait loci in mice.

We previously reported the analysis of genome-wide expression profiles and various diabetes-related traits in a segregating cross between inbred mouse strains C57BL/6J (B6) and DBA/2J (DBA). By considering transcript levels as quantitative traits, we identified several thousand expression quantitative trait loci (eQTL) with LOD score >4.3.

Investigation of molecular beacon aptamer-based bioassay for platelet-derived growth factor detection.

This report describes studies on the use of a molecular-beacon aptamer (MBA) as a synthetic high-affinity DNA probe that exhibits fluorescence resonance energy transfer (FRET) in response to a specific protein biomarker, platelet-derived growth factor (PDGF). As a step toward the application of the MBA in a fluorescence-based assay for biological specimens, we examined the influence of certain physical and chemical parameters of incubation that would affect DNA conformation and DNA-backbone modification, and thus improve nuclease resistance. This bioassay is compatible with pH, temperature, and monovalent cation levels typically encountered in biological samples, and phosphorothioate backbone-modified MBA is able to exhibit specific FRET.

A retrospective study of mortality in Pennsylvania captive white-tailed deer (Odocoileus virginianus): 20000--2003.

The postmortem records of 160 white-tailed deer (Odocoileus virginianus) submitted for necropsy examination from 59 separate Pennsylvania captive deer farms over a 3.5-year period were reviewed to determine the primary cause of death of each animal. The most common causes of death were bronchopneumonia (39 cases), enterocolitis (30 cases), malnutrition (13 cases), and trauma (11 cases).

Molecular beacons.

This opinion covers the field of molecular beacons (MBs), in which nucleic acids are molecularly engineered to have unique functions for the investigation of biomolecules. Molecular beacons have been used in a variety of formats, and this review discusses four: first, in vitro RNA and DNA monitoring; second, biosensors and biochips based on MBs; third, real-time monitoring of genes and gene expression in living systems; and finally, the next generation of molecular beacons that will be highly useful for studies with proteins, molecular beacon aptamers. These unique applications have shown that MBs holds great potential in genomics and proteomics where real-time molecular recognition with high sensitivity and excellent specificity is critical.

Functionalized nanoparticles for liquid atmospheric pressure matrix-assisted laser desorption/ionization peptide analysis.

Nanoparticles for the extraction of peptides and subsequent analysis using atmospheric pressure matrix-assisted laser desorption/ionization (APMALDI) have been evaluated. The atmospheric pressure source allows for particles to be directly introduced in the liquid matrix, minimizing sample loss and analysis time. Described in this work are two sample preparation procedures for liquid APMALDI analysis: a C18 functionalized silica nanoparticle for hydrophobic extractions, and an aptamer functionalized magnetite core nanoparticle for rapid, affinity extractions.

Modelling sheet-flow sediment transport in wave-bottom boundary layers using discrete-element modelling.

Sediment transport in oscillatory boundary layers is a process that drives coastal geomorphological change. Most formulae for bed-load transport in nearshore regions subsume the smallest-scale physics of the phenomena by parametrizing interactions amongst particles. In contrast, we directly simulate granular physics in the wave-bottom boundary layer using a discrete-element model comprised of a three-dimensional particle phase coupled to a one-dimensional fluid phase via Newton's third law through forces of buoyancy, drag and added mass.

Laser phase noise reduction for industrial interferometric applications.

Laser ultrasound is a technique used for the ultrasonic inspection of composites during manufacturing of advanced jet fighters. With this technique laser interferometry is used to detect ultrasonic displacements generated by a laser. In theory, the signal-to-noise ratio is proportional to the square root of the collected detection light.

Thematic review series: The pathogenesis of atherosclerosis. Toward a biological network for atherosclerosis.

The goal of systems biology is to define all of the elements present in a given system and to create an interaction network between these components so that the behavior of the system, as a whole and in parts, can be explained under specified conditions. The elements constituting the network that influences the development of atherosclerosis could be genes, pathways, transcript levels, proteins, or physiologic traits. In this review, we discuss how the integration of genetics and technologies such as transcriptomics and proteomics, combined with mathematical modeling, may lead to an understanding of such networks.

Bionanotechnology based on silica nanoparticles.

We have developed uniform core/shell nanoparticles, consisting of a silica layer coating and pigments or magnetite core, using a water-in-oil microemulsion method. The nanoparticles are highly luminescent and photostable with the size ranging from 5 nm to 400 nm. Bioconjugation of these silica nanoparticles adds unique biofunctions with various molecules such as enzymes, antibodies, and DNA molecules.

ENU large-scale mutagenesis and quantitative trait linkage (QTL) analysis in mice: novel technologies for searching polygenetic determinants of craniofacial abnormalities.

Discrepancies in size and shape of the jaws are the underlying etiology in many orthodontic and orthognathic surgery patients. Genetic factors combined with environmental interactions have been postulated to play a causal or contributory role in these craniofacial abnormalities. Along with the soon-to-be-available complete human and mouse genomic sequence data, mouse mutants have become a valuable tool in the functional mapping of genes involved in the development of human maxillofacial dysmorphologies.

Standardising Client Identification across Adelaide Public Hospitals - An Update.

To be able to integrate health information across multiple systems and locations, it is essential that the collection and maintenance of key client identifying demographic data be standardised. South Australia is now moving towards a rigorous approach of client identification across the eight public metropolitan hospitals to support the rollout of a clinical information system. The system is being implemented for all clinical services and an estimated 8,000 doctors, nurses and allied health professionals have been trained in its use.

Genetic loci for diet-induced atherosclerotic lesions and plasma lipids in mice.

Genetic factors independent of those affecting plasma lipid levels are a major contributor to risk for atherosclerosis in humans, yet the basis for these is poorly understood. This study examined plasma lipids and diet-induced atherosclerosis in 16-month-old female mice of strains C56BL/6J and DBA/2J. Mice of the parental strains, from recombinant inbred strains derived from these (BXD RI), and F(2) progeny were fed an atherogenic diet for 16 weeks, beginning at 1 year of age.

Genetic backgrounds but not sizes of atherosclerotic lesions determine medial destruction in the aortic root of apolipoprotein E-deficient mice.

Objective: Destruction of the elastic media is the most striking histologic feature of atherosclerotic aortic aneurysms. Apolipoprotein E-deficient (apoE-/-) mice fed a Western diet develop advanced atherosclerotic lesions in the aorta. We sought to assess the integrity of atherosclerotic aortic walls in 2 apoE-/- strains, C57BL/6 (B6) and C3H/HeJ (C3H) that differ markedly in atherosclerosis susceptibility.