Mutations in mitochondrial carrier family gene SLC25A38 cause nonsyndromic autosomal recessive congenital sideroblastic anemia.

The sideroblastic anemias are a heterogeneous group of congenital and acquired hematological disorders whose morphological hallmark is the presence of ringed sideroblasts--bone marrow erythroid precursors containing pathologic iron deposits within mitochondria. Here, by positional cloning, we define a previously unknown form of autosomal recessive nonsyndromic congenital sideroblastic anemia, associated with mutations in the gene encoding the erythroid specific mitochondrial carrier family protein SLC25A38, and demonstrate that SLC25A38 is important for the biosynthesis of heme in eukaryotes.

The systems analysis approach to mechanosensory coding.

An important problem in neuroscience is to obtain quantitative knowledge of how information is represented, or encoded, in the signals that nerve cells process and transmit. Sensory receptors have provided important models for the study of neural coding because their inputs can often be relatively easily controlled and measured, while the resultant activity is recorded. A variety of engineering concepts have been successfully applied to physiological sciences, particularly those related to control of dynamic systems.

How well can captive breeding programs conserve biodiversity? A review of salmonids.

Captive breeding programs are increasingly being initiated to prevent the imminent extinction of endangered species and/or populations. But how well can they conserve genetic diversity and fitness, or re-establish self-sustaining populations in the wild? A review of these complex questions and related issues in salmonid fishes reveals several insights and uncertainties. Most programs can maintain genetic diversity within populations over several generations, but available research suggests the loss of fitness in captivity can be rapid, its magnitude probably increasing with the duration in captivity.

Mixed evidence for reduced local adaptation in wild salmon resulting from interbreeding with escaped farmed salmon: complexities in hybrid fitness.

Interbreeding between artificially-selected and wild organisms can have negative fitness consequences for the latter. In the Northwest Atlantic, farmed Atlantic salmon recurrently escape into the wild and enter rivers where small, declining populations of wild salmon breed. Most farmed salmon in the region derive from an ancestral source population that occupies a nonacidified river (pH 6.

Global epidemiology of multiple birth.

Multiple births, which account for approximately 3% of births and 14% of infant deaths, are increasing in frequency. Multiple birth rates began to decline in the 1950s, reaching a minimum in the 1970s and rising since then. Both twin and triplet rates followed the same rising trend until 1998, after which triplet birth rates began to decline while twin birth rates continued to rise.

Cost efficiency of reducing multiple births.

Reducing the frequency of multiple pregnancies would help to prevent prematurity associated with multiple births. Premature newborns may require extensive and costly medical interventions. Long-term disability also involves health, social and educational services during childhood, which may cost ten-fold more for twin than singleton births.

Expert Canadian consensus suggestions on the rational, clinical use of ziprasidone in the treatment of schizophrenia and related psychotic disorders.

Many atypical antipsychotic medications are becoming available for clinical use. Ziprasidone is a recent addition to this group and is expected to become available for clinical use in Canada in 2005. Ziprasidone has some significant differences compared with other atypicals currently available in Canada.

Potential for anthropogenic disturbances to influence evolutionary change in the life history of a threatened salmonid.

Although evolutionary change within most species is thought to occur slowly, recent studies have identified cases where evolutionary change has apparently occurred over a few generations. Anthropogenically altered environments appear particularly open to rapid evolutionary change over comparatively short time scales. Here, we consider a Pacific salmon population that may have experienced life-history evolution, in response to habitat alteration, within a few generations.

Consequences of sexual selection for fisheries-induced evolution: an exploratory analysis.

Reproductive behaviour and mating system complexity may influence fisheries-induced evolution. Mate choice and intrasexual competition might favour late-, large-maturing genotypes in contrast to the selection imposed by many fisheries. Here, we simulate changes to the mean and variance in body size of Atlantic cod (Gadus morhua) concomitant with increased fishing intensity.

Conservation genetics as applied evolution: from genetic pattern to evolutionary process.

Conservation genetics can be seen as the effort to influence the evolutionary process in ways that enhance the persistence of populations. Much published research in the field applies genetic sampling techniques to infer population parameters from the patterns of variation in threatened populations. The limited resolution of these inferences seems to yield limited confidence which results in conservative policy recommendations.

Construction and characterization of single-chain variable fragment antibodies directed against the Bordetella pertussis surface adhesins filamentous hemagglutinin and pertactin.

A single-chain variable fragment (scFv) antibody library against Bordetella pertussis was constructed using M13 phage display. The library was enriched for phages surface displaying functional scFv by biopanning against B. pertussis immobilized on polystyrene plates.

Methods for selecting fixed-effect models for heterogeneous codon evolution, with comments on their application to gene and genome data.

Background: Models of codon evolution have proven useful for investigating the strength and direction of natural selection. In some cases, a priori biological knowledge has been used successfully to model heterogeneous evolutionary dynamics among codon sites. These are called fixed-effect models, and they require that all codon sites are assigned to one of several partitions which are permitted to have independent parameters for selection pressure, evolutionary rate, transition to transversion ratio or codon frequencies.

Infrared multiphoton dissociation of the siderophore enterobactin and its Fe(III) complex. Influence of Fe(III) binding on dissociation kinetics and relative energetics.

The dissociation pathways of the siderophore enterobactin and its complex with Fe(III) were examined using infrared multiphoton dissociation (IRMPD). Under experimental conditions (pH = 3.5), both compounds' electrospray spectra exhibited exclusively singly-charged anions.

Using limb movements to improve spatial neglect: the role of functional electrical stimulation.

Purpose: Spatial neglect is common after right-hemisphere stroke and has proven resilient to a number of therapeutic interventions. Both active and experimenter-induced passive movements of the left limb in left hemispace have been shown to ameliorate neglect in subsets of patients by improving performance on tasks requiring attention to the left side of space. However, the high incidence of contralesional hemiparesis and poor motor recovery in neglect makes active limb movement therapies applicable to only a small subset of patients.

The sexuality and social performance of androgen-deprived (castrated) men throughout history: implications for modern day cancer patients.

Androgen-deprivation therapy (ADT) via either surgical or chemical castration is the standard treatment for advanced prostate cancer (PCa). In North America, it is estimated that more than 40,000 men start ADT each year. The side effects of this treatment are extensive and include gynecomastia, erectile dysfunction, and reduced libido.

The life and work of Donald Olding Hebb.

In his book, The Organization of Behavior, Donald Olding Hebb introduced the concepts of synaptic plasticity and cell assemblies to provide a theory of the neurophysiological basis of behaviour. Hebb's ideas, as presented in this book and other writings, influenced all areas of psychology and neuroscience. Hebb was born in Chester, Nova Scotia, Canada and attended Dalhousie University (BA, 1925) and McGill University (MA, 1932).

Breaking bonds in the atomic force microscope: extracting information.

A theoretical framework is developed to analyze molecular bond breaking in dynamic force spectroscopy using atomic force microscopy (AFM). An analytic expression of the observed bond breaking probability as a function of force is obtained in terms of the relevant physical parameters. Three different experimental realizations are discussed, in which (i) the force is increased linearly in time, and (ii) the AFM cantilever is moved at constant speed, and (iii) the force is held constant.

Medical education for rural areas: opportunities and challenges for information and communications technologies.

Resources in medical education are not evenly distributed and access to education can be more problematic in rural areas. Similar to telemedicine's positive influence on health care access, advances in information and communications technologies (ICTs) increase opportunities for medical education. This paper provides a descriptive overview of the use of ICTs in medical education and suggests a conceptual model for reviewing ICT use in medical education, describes specific ICTs and educational interventions, and discusses opportunities and challenges of ICT use, especially in rural areas.

Proximal effects of dependency and self-criticism: conceptual and methodological challenges for depressive vulnerability research.

Research and theorizing on vulnerability to depression has expanded considerably in the past 40 years. However, there are a number of challenges and opportunities that cannot be adequately resolved or fully exploited within models of vulnerability that are typically investigated. Continued progress in understanding the link between vulnerability factors and mood depends on a fuller understanding of depressive vulnerability factors themselves.