Inheritance of Stress Responses via Small Non-Coding RNAs in Invertebrates and Mammals

While reports on the generational inheritance of a parental response to stress have been widely reported in animals, the molecular mechanisms behind this phenomenon have only recently emerged. The booming interest in epigenetic inheritance has been facilitated in part by the discovery that small non-coding RNAs are one of its principal conduits. Discovered 30 years ago in the Caenorhabditis elegans nematode, these small molecules have since cemented their critical roles in regulating virtually all aspects of eukaryotic development. Here, we provide an overview on the current understanding of epigenetic inheritance in animals, including mice and C. elegans, as it pertains to stresses such as temperature, nutritional, and pathogenic encounters. We focus on C. elegans to address the mechanistic complexity of how small RNAs target their cohort mRNAs to effect gene expression and how they govern the propagation or termination of generational perdurance in epigenetic inheritance. Presently, while a great amount has been learned regarding the heritability of gene expression states, many more questions remain unanswered and warrant further investigation.

Epigenetic regulation of nervous system development and function

Building a brain is complicated but maintaining one may be an even greater challenge. Epigenetic mechanisms, including DNA methylation, histone and chromatin modifications, and the actions of non-coding RNAs, play an indispensable role in both. They orchestrate long-term changes in gene expression that underpin establishment of cellular identity as well as the distinct functionality of each cell type, while providing the needed plasticity for the brain to respond to a changing environment. The rapid expansion of studies on these epigenetic mechanisms over the last few decades has brought an evolving definition of the term epigenetics, including in the specialized context of the nervous system. The goal of this special issue is thus not only to bring a greater understanding of the myriad ways in which epigenetic mechanisms regulate nervous system development and function, but also to provide a platform for discussion of what is and what is not epigenetics. To this end, the editors have compiled a collection of review articles highlighting some of the remarkable breadth of epigenetic mechanisms that act at all stages of neuronal development and function, spanning from neurodevelopment, through learning and memory, and neurodegeneration.

Somatic aging pathways regulate reproductive plasticity in Caenorhabditis elegans

In animals, early-life stress can result in programmed changes in gene expression that can affect their adult phenotype. In C. elegans nematodes, starvation during the first larval stage promotes entry into a stress-resistant dauer stage until environmental conditions improve. Adults that have experienced dauer (postdauers) retain a memory of early-life starvation that results in gene expression changes and reduced fecundity. Here, we show that the endocrine pathways attributed to the regulation of somatic aging in C. elegans adults lacking a functional germline also regulate the reproductive phenotypes of postdauer adults that experienced early-life starvation. We demonstrate that postdauer adults reallocate fat to benefit progeny at the expense of the parental somatic fat reservoir and exhibit increased longevity compared to controls. Our results also show that the modification of somatic fat stores due to parental starvation memory is inherited in the F₁ generation and may be the result of crosstalk between somatic and reproductive tissues mediated by the germline nuclear RNAi pathway.

piRNAs and endo-siRNAs: Small molecules with large roles in the nervous system

Since their discovery, small non-coding RNAs have emerged as powerhouses in the regulation of numerous cellular processes. In addition to guarding the integrity of the reproductive system, small non-coding RNAs play critical roles in the maintenance of the soma. Accumulating evidence indicates that small non-coding RNAs perform vital functions in the animal nervous system such as restricting the activity of deleterious transposable elements, regulating nerve regeneration, and mediating learning and memory. In this review, we provide an overview of the current understanding of the contribution of two major classes of small non-coding RNAs, piRNAs and endo-siRNAs, to the nervous system development and function, and present highlights on how the dysregulation of small non-coding RNA pathways can assist in understanding the neuropathology of human neurological disorders.

Acoustic Hemifields in the Spatial Release from Masking of Speech by Noise

The Hearing-in-Noise Test (HINT) is able to measure the benefit to speech intelligibility in noise conferred when the noise masker is displaced 90 degrees in eccentricity from a speech source located at zero degrees azimuth. Both psychoacoustic and neurophysiological data suggest that the perceptual benefit of the 90-degree azimuth separation would be greatest if the speech and noise were presented in different acoustic hemifields, and would be smallest if the two sources were in the same acoustic hemifield. The present study tested this hypothesis directly in ten normal-hearing adult listeners. Using the HINT stimuli, we confirmed the hypothesis. Release from masking scores averaged 8.61 dB for "between-hemifield" conditions, 6.05 dB for HINT conditions, and 1.27 dB for "within-hemifield" conditions, even though all stimulus configurations retained a 90-degree angular separation of speech and noise. These data indicate that absolute separation of speech and noise alone is insufficient to guarantee a significant release from masking, and they suggest that what matters is the location of the stimulus elements relative to the left and right spatial perceptual channels. La Prueba de Audición en Ruido (HINT) permite medir los beneficios para la inteligibilidad del lenguaje en ruido que ocurre cuando el enmascarador de ruido es desplazado 90 grados de la fuente de lenguaje localizada a 0 grados azimut. Tanto los datos psicoacústicos como neurofisiológicos sugieren que el beneficio perceptual de la separación de 90 grados azimut sería mayor si el lenguaje y el ruido fueran presentados en diferentes hemicampos acústicos, y sería menor si las dos fuentes estuvieran en el mismo hemicampo. El presente estudio evaluó esta hipótesis directamente en diez sujetos adultos normo-oyentes. Utilizando los estímulos del HINT, confirmamos la hipótesis. Los puntajes de liberación del enmascaramiento promediaron 8.61 dB para las condiciones de "entre-hemicampos". 6.05 dB para las condiciones del HINT, y 1.27 para las condiciones "dentro del hemicampo", a pesar de que la configuración de todos los estímulos retuvo una separación angular de 90 grados entre el lenguaje y el ruido. Estos datos indican que la separación absoluta del ruido y lenguaje solos es insuficiente para garantizar una liberación significativa del enmascaramiento, y sugieren que lo que importa es la localización de los elementos del estímulo con relación a los canales perceptuales espaciales derecho e izquierdo.

The Role of Emotional Intelligence in Community Integration and Return to Work After Acquired Brain Injury

OBJECTIVE

To investigate whether emotional intelligence (EI) skills measured via the Perceiving, Understanding, and Managing Emotions branches of the Mayer-Salovey-Caruso Emotional Intelligence Test V2.0 are associated with community integration (CI) and return to work (RTW) after moderate-to-severe acquired brain injury (ABI), after accounting for other established predictors.

DESIGN

Retrospective cohort study.

SETTING

Outpatient follow-up services within 2 specialist ABI rehabilitation centers in Melbourne, Australia.

PARTICIPANTS

Individuals (N=82) with moderate-to-severe ABI discharged from inpatient rehabilitation and living in the community (2mo to 7y postinjury).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Community Integration Questionnaire scores for the total sample (N=82; age range 18-80) and RTW status (employed vs not employed) for the subset of participants employed prior to ABI (n=71; age range 19-66).

RESULTS

Hierarchical logistic and multiple regression analyses were used to examine the unique contribution of Perceiving, Understanding, and Managing Emotions scores to RTW and CI, after controlling for demographic, injury-related, psychological, and cognitive predictors. As a set, the 3 EI variables did not explain incremental variance in outcomes. However, individually, Understanding Emotions predicted RTW (adjusted odds ratio=3.10, P=.03), χ² (12)=35.52, P<.001, and Managing Emotions predicted CI (β=0.23, P=.036), F_12,69=5.14, P<.001.

CONCLUSION

Although the EI constructs in combination did not improve prediction beyond the effects of established variables, individual components of strategic EI may be important for specific participation outcomes after ABI.

Early experiences mediate distinct adult gene expression and reproductive programs in Caenorhabditis elegans

Environmental stress during early development in animals can have profound effects on adult phenotypes via programmed changes in gene expression. Using the nematode C. elegans, we demonstrated previously that adults retain a cellular memory of their developmental experience that is manifested by differences in gene expression and life history traits; however, the sophistication of this system in response to different environmental stresses, and how it dictates phenotypic plasticity in adults that contribute to increased fitness in response to distinct environmental challenges, was unknown. Using transcriptional profiling, we show here that C. elegans adults indeed retain distinct cellular memories of different environmental conditions. We identified approximately 500 genes in adults that entered dauer due to starvation that exhibit significant opposite (“seesaw”) transcriptional phenotypes compared to adults that entered dauer due to crowding, and are distinct from animals that bypassed dauer. Moreover, we show that two-thirds of the genes in the genome experience a 2-fold or greater seesaw trend in gene expression, and based upon the direction of change, are enriched in large, tightly linked regions on different chromosomes. Importantly, these transcriptional programs correspond to significant changes in brood size depending on the experienced stress. In addition, we demonstrate that while the observed seesaw gene expression changes occur in both somatic and germline tissue, only starvation-induced changes require a functional GLP-4 protein necessary for germline development, and both programs require the Argonaute CSR-1. Thus, our results suggest that signaling between the soma and the germ line can generate phenotypic plasticity as a result of early environmental experience, and likely contribute to increased fitness in adverse conditions and the evolution of the C. elegans genome.

Environmental stress during early development in animals can have profound effects on adult behavior and physiology due to programmed changes in gene expression. However, whether different stresses result in distinct changes in traits that allow stressed animals to better survive and reproduce in future adverse conditions is largely unknown. Using the animal model system, C. elegans, we show that adults that experienced starvation exhibit opposite (“seesaw”) genome-wide gene expression changes compared to adults that experienced crowding, and are distinct from animals that experienced favorable conditions. Genes that are similarly up- or downregulated due to either starvation or crowding are located in clusters on the same chromosomes. Importantly, these gene expression changes of differently-stressed animals result in corresponding changes in progeny number, a life history trait of evolutionary significance. These distinct gene expression programs require different signaling pathways that communicate across somatic and germline tissue types. Thus, different environmental stresses experienced early in development induce distinct signaling mechanisms to result in changes in gene expression and reproduction in adults, and likely contribute to increased survival in future adverse conditions.

Linking the environment, DAF-7/TGFβ signaling and LAG-2/DSL ligand expression in the germline stem cell niche

The developmental accumulation of proliferative germ cells in the C. elegans hermaphrodite is sensitive to the organismal environment. Previously, we found that the TGFβ signaling pathway links the environment and proliferative germ cell accumulation. Neuronal DAF-7/TGFβ causes a DAF-1/TGFβR signaling cascade in the gonadal distal tip cell (DTC), the germline stem cell niche, where it negatively regulates a DAF-3 SMAD and DAF-5 Sno-Ski. LAG-2, a founding DSL ligand family member, is produced in the DTC and activates the GLP-1/Notch receptor on adjacent germ cells to maintain germline stem cell fate. Here, we show that DAF-7/TGFβ signaling promotes expression of lag-2 in the DTC in a daf-3-dependent manner. Using ChIP and one-hybrid assays, we find evidence for direct interaction between DAF-3 and the lag-2 promoter. We further identify a 25 bp DAF-3 binding element required for the DTC lag-2 reporter response to the environment and to DAF-7/TGFβ signaling. Our results implicate DAF-3 repressor complex activity as a key molecular mechanism whereby the environment influences DSL ligand expression in the niche to modulate developmental expansion of the germline stem cell pool.

Assessment of emotion processing skills in acquired brain injury using an ability-based test of emotional intelligence

Social and emotional problems are commonly reported after moderate to severe acquired brain injury (ABI) and pose a significant barrier to rehabilitation. However, progress in assessment of emotional skills has been limited by a lack of validated measurement approaches. This study represents the first formal psychometric evaluation of the use of the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) V2.0 as a tool for assessing skills in perceiving, using, understanding and managing emotions following ABI. The sample consisted of 82 participants aged 18-80 years in the postacute phase of recovery (2 months-7 years) after moderate to severe ABI. Participants completed the MSCEIT V2.0 and measures of cognition and mood. Sociodemographic and clinical variables were collated from participant interview and medical files. Results revealed deficits across all MSCEIT subscales (approximately 1 SD below the normative mean). Internal consistency was adequate at overall, area, and branch levels, and MSCEIT scores correlated in expected ways with key demographic, clinical, cognitive, and mood variables. MSCEIT performance was related to injury severity and clinician-rated functioning after ABI. Confirmatory factor analysis favored a 3-factor model of EI due to statistical redundancy of the Using Emotions branch. Overall, these findings suggest that the MSCEIT V2.0 is sensitive to emotion processing deficits after moderate to severe ABI, and can yield valid and reliable scores in an ABI sample. In terms of theoretical contributions, our findings support a domain-based, 3-factor approach for characterizing emotion-related abilities in brain-injured individuals. (PsycINFO Database Record

The Role of Trait and State Absorption in the Enjoyment of Music

Little is known about the role of state versus trait characteristics on our enjoyment of music. The aim of this study was to investigate the influence of state and trait absorption upon preference for music, particularly preference for music that evokes negative emotions. The sample consisted of 128 participants who were asked to listen to two pieces of self-selected music and rate the music on variables including preference and felt and expressed emotions. Participants completed a brief measure of state absorption after listening to each piece, and a trait absorption inventory. State absorption was strongly positively correlated with music preference, whereas trait absorption was not. Trait absorption was related to preference for negative emotions in music, with chi-square analyses demonstrating greater enjoyment of negative emotions in music among individuals with high trait absorption. This is the first study to show that state and trait absorption have separable and distinct effects on a listener's music experience, with state characteristics impacting music enjoyment in the moment, and trait characteristics influencing music preference based on its emotional content.

A Method for Obtaining Large Populations of Synchronized Caenorhabditis elegans Dauer Larvae

The C. elegans dauer is an attractive model with which to investigate fundamental biological questions, such as how environmental cues are sensed and are translated into developmental decisions through a series of signaling cascades that ultimately result in a transformed animal. Here we describe a simple method of using egg white plates to obtain highly synchronized purified dauers that can be used in downstream applications requiring large quantities of dauers or postdauer animals.

Developmental programming modulates olfactory behavior in C. elegans via endogenous RNAi pathways

Environmental stress during early development can impact adult phenotypes via programmed changes in gene expression. C. elegans larvae respond to environmental stress by entering the stress-resistant dauer diapause pathway and resume development once conditions improve (postdauers). Here we show that the osm-9 TRPV channel gene is a target of developmental programming and is down-regulated specifically in the ADL chemosensory neurons of postdauer adults, resulting in a corresponding altered olfactory behavior that is mediated by ADL in an OSM-9-dependent manner. We identify a cis-acting motif bound by the DAF-3 SMAD and ZFP-1 (AF10) proteins that is necessary for the differential regulation of osm-9, and demonstrate that both chromatin remodeling and endo-siRNA pathways are major contributors to the transcriptional silencing of the osm-9 locus. This work describes an elegant mechanism by which developmental experience influences adult phenotypes by establishing and maintaining transcriptional changes via RNAi and chromatin remodeling pathways.

DOI:http://dx.doi.org/10.7554/eLife.11642.001

Increasing evidence suggests that experiencing stressful environments early on in life can have profound effects on the health and behavior of adults. For example, stressful conditions in the womb have been linked to adult depression and metabolic disorders. These effects are thought to be the result of changes in the way that genes in specific tissues are regulated in the individuals that have experienced the stress. However, it is not clear how a particular stress can cause long-term changes in gene activity in specific tissues.

A microscopic worm called Caenorhabditis elegans is often used as a simple animal model to study how animals develop and behave. Previous studies have shown that adult worms that experienced stress early in life show differences in behavior and gene activity compared to genetically identical worms that did not experience the stress. Here, Sims, Ow et al. asked what signals are required for these changes to happen.

The experiments show that a gene called osm-9 – which plays a role in the nervous system – is less active in sensory nerve cells in worms that experienced stress early on in life. This loss of activity resulted in the worms being unable to respond to a particular odor. Two proteins called DAF-3 and ZFP-1 are able to bind to a section of DNA in the osm-9 gene to decrease its activity in response to stress. These proteins are similar to human proteins that are important for development and are associated with some types of leukemia. Further experiments show that small molecules of ribonucleic acid in the “RNA interference” pathway also help to decrease the activity of osm-9 after stress.

Together, Sims, Ow et al.’s findings suggest that environmental conditions in early life regulate the osm-9 gene through the coordinated effort of DAF-3, ZFP-1 and the RNA interference pathway. The next steps are to investigate how these molecules are able to target osm-9 and to identify other proteins that regulate gene activity in response to stress in early life.

DOI:http://dx.doi.org/10.7554/eLife.11642.002

Small RNA library cloning procedure for deep sequencing of specific endogenous siRNA classes in Caenorhabditis elegans

In recent years, distinct classes of small RNAs ranging in size from ~21 to 26 nucleotides have been discovered and shown to play important roles in a wide array of cellular functions. Because of the abundance of these small RNAs, library preparation from an RNA sample followed by deep sequencing provides the identity and quantity of a particular class of small RNAs. In this chapter we describe a detailed protocol for preparing small RNA libraries for deep sequencing on the Illumina platform from the nematode C. elegans.

RNAi pathways contribute to developmental history-dependent phenotypic plasticity in C. elegans

Early environmental experiences profoundly influence adult phenotypes through complex mechanisms that are poorly understood. We previously showed that adult Caenorhabditis elegans that transiently passed through the stress-induced dauer larval stage (post-dauer adults) exhibit significant changes in gene expression profiles, chromatin states, and life history traits when compared with adults that bypassed the dauer stage (control adults). These wild-type, isogenic animals of equivalent developmental stages exhibit different signatures of molecular marks that reflect their distinct developmental trajectories. To gain insight into the mechanisms that contribute to these developmental history-dependent phenotypes, we profiled small RNAs from post-dauer and control adults by deep sequencing. RNA interference (RNAi) pathways are known to regulate genome-wide gene expression both at the chromatin and post-transcriptional level. By quantifying changes in endogenous small interfering RNA (endo-siRNA) levels in post-dauer as compared with control animals, our analyses identified a subset of genes that are likely targets of developmental history-dependent reprogramming through a complex RNAi-mediated mechanism. Mutations in specific endo-siRNA pathways affect expected gene expression and chromatin state changes for a subset of genes in post-dauer animals, as well as disrupt their increased brood size phenotype. We also find that both chromatin state and endo-siRNA distribution in dauers are unique, and suggest that remodeling in dauers provides a template for the subsequent establishment of adult post-dauer profiles. Our results indicate a role for endo-siRNA pathways as a contributing mechanism to early experience-dependent phenotypic plasticity in adults, and describe how developmental history can program adult physiology and behavior via epigenetic mechanisms.

Complementary and alternative treatment use for autism spectrum disorders

Autism spectrum disorders (ASD) have rapidly become one of the more frequent reasons for seeking diagnosis and treatment. Depending on health care services available, the standard treatment options are often limited; many parents turn to complementary and alternative medicine (CAM) approaches. CAM treatments and some of the factors that may contribute to parents' decisions to use CAM treatments were examined using a web-based survey. Four general factors emerges as influencing the decision-making processes of parents/caregivers - severity, child acceptance of the treatment, marital status, and educational level. Notably, research support did not emerge as contributing to variance for CAM use.

Developmental changes in anger expression and attention focus: learning to wait

Being able to wait is an essential part of self-regulation. In the present study, the authors examined the developmental course of changes in the latency to and duration of target-waiting behaviors by following 65 boys and 55 girls from rural and semirural economically strained homes from ages 18 months to 48 months. Age-related changes in latency to and duration of children's anger expressions and attention focus (e.g., self-initiated distraction) during an 8-min wait for a gift were found. On average, at 18 and 24 months of age, children were quick to react angrily and slower to shift attention away from the desired object than they were at later ages. Over time, children were quicker to distract themselves. By 36 months, distractions occurred before children expressed anger, and anger expressions were briefer. At 48 months, children typically made a quick bid to their mothers about having to wait before distracting themselves; on average, they did not appear angry until the latter half of the wait. Unexpectedly, children bid to their mothers as much at age 48 months as they had at 18 months; however, bids became less angry as children got older. Developmental changes in distraction and bidding predicted age-related changes in the latency to anger. Findings are discussed in terms of the neurocognitive control of attention around age 30 months, the limitations of children's self-regulatory efforts at age 48 months, and the importance of fostering children's ability to forestall, as well as modulate, anger.

A cellular memory of developmental history generates phenotypic diversity in C. elegans

Early life experiences have a major impact on adult phenotypes [1-3]. However, the mechanisms by which animals retain a cellular memory of early experience are not well understood. Here we show that adult wild-type Caenorhabditis elegans that transiently pass through the stress-resistant dauer larval stage exhibit distinct gene expression profiles and life history traits, as compared to adult animals that bypassed this stage. Using chromatin immunoprecipitation experiments coupled with massively parallel sequencing, we found that genome-wide levels of specific histone tail modifications are markedly altered in postdauer animals. Mutations in subsets of genes implicated in chromatin remodeling abolish, or alter, the observed changes in gene expression and life history traits in postdauer animals. Modifications to the epigenome as a consequence of early experience may contribute in part to a memory of early experience and generate phenotypic variation in an isogenic population.

Isotope turnover studies in uncontrolled diabetes and the effects of insulin

Turnover rates of glucose, free fatty acids (FFA) and leucine have been measured in newly diagnosed, uncontrolled insulin-dependent diabetic (IDD) patients. The results have been compared with data collected from the same patients while on conventional insulin therapy as well as after overnight intravenous infusion of insulin with sustained normoglycaemia. The data have been analysed by compartmental and non-compartmental methods and the results have been compared with simultaneously collected data on respiratory exchange. Oxidation rates of 14C-labelled substrates have also been measured. Tracer studies were done on established diabetics after insulin withdrawal and subsequent intravenous infusion of insulin at different rates. The results confirm the in vivo importance of the glucose-fatty acid cycle, indicating that when glucose, FFA and ketone bodies are available in excess it is FFA and ketones that are metabolized in preference to glucose. The data emphasize the importance of increased production rates rather than decreased utilization rates in producing high concentrations of substrates in the plasma of insulin-deficient patients.

Differential rates of local and global homogenization in centromere satellites from Arabidopsis relatives

Higher eukaryotic centromeres contain thousands of satellite repeats organized into tandem arrays. As species diverge, new satellite variants are homogenized within and between chromosomes, yet the processes by which particular sequences are dispersed are poorly understood. Here, we isolated and analyzed centromere satellites in plants separated from Arabidopsis thaliana by 5-20 million years, uncovering more rapid satellite divergence compared to primate alpha-satellite repeats. We also found that satellites derived from the same genomic locus were more similar to each other than satellites derived from disparate genomic regions, indicating that new sequence alterations were homogenized more efficiently at a local, rather than global, level. Nonetheless, the presence of higher-order satellite arrays, similar to those identified in human centromeres, indicated limits to local homogenization and suggested that sequence polymorphisms may play important functional roles. In two species, we defined more extensive polymorphisms, identifying physically separated and highly distinct satellite types. Taken together, these data show that there is a balance between plant satellite homogenization and the persistence of satellite variants. This balance could ultimately generate sufficient sequence divergence to cause mating incompatibilities between plant species, while maintaining adequate conservation within a species for centromere activity.

Whole-genome fractionation rapidly purifies DNA from centromeric regions

The condensed centromeric regions of higher eukaryotic chromosomes contain satellite sequences, transposons and retroelements, as well as transcribed genes that perform a variety of functions. These chromosomal domains nucleate kinetochores, mediate sister chromatid cohesion and inhibit recombination, yet their characterization has often lagged behind that of chromosome arms. Here, we describe a whole-genome fractionation technique that rapidly identifies bacterial artificial chromosome (BAC) clones derived from plant centromeric regions. This approach, which relies on hybridization of methylated genomic DNA, revealed BACs that correspond to the genetically mapped and sequenced Arabidopsis thaliana centromeric regions. Extending this method to other species in the Brassicaceae family identified centromere-linked clones and provided genome-wide estimates of methylated DNA abundance. Sequencing these clones will elucidate the changes that occur during plant centromere evolution. This genomic fractionation technique could identify centromeric DNA in genomes with similar methylation and repetitive DNA content, including those from crops and mammals.

The rapidly evolving field of plant centromeres

Meiotic and mitotic chromosome segregation are highly conserved in eukaryotic organisms, yet centromeres--the chromosomal sites that mediate segregation--evolve extremely rapidly. Plant centromeres have DNA elements that are shared across species, yet they diverge rapidly through large- and small-scale changes. Over evolutionary time-scales, centromeres migrate to non-centromeric regions and, in plants, heterochromatic knobs can acquire centromere activity. Discerning the functional significance of these changes will require comparative analyses of closely related species. Combined with functional assays, continued efforts in plant genomics will uncover key DNA elements that allow centromeres to retain their role in chromosome segregation while allowing rapid evolution.

Metabolic redesign of vitamin E biosynthesis in plants for tocotrienol production and increased antioxidant content

Tocotrienols are the primary form of vitamin E in seeds of most monocot plants, including cereals such as rice and wheat. As potent antioxidants, tocotrienols contribute to the nutritive value of cereal grains in human and livestock diets. cDNAs encoding homogentisic acid geranylgeranyl transferase (HGGT), which catalyzes the committed step of tocotrienol biosynthesis, were isolated from barley, wheat and rice seeds. Transgenic expression of the barley HGGT in Arabidopsis thaliana leaves resulted in accumulation of tocotrienols, which were absent from leaves of nontransformed plants, and a 10- to 15-fold increase in total vitamin E antioxidants (tocotrienols plus tocopherols). Overexpression of the barley HGGT in corn seeds resulted in an increase in tocotrienol and tocopherol content of as much as six-fold. These results provide insight into the genetic basis for tocotrienol biosynthesis in plants and demonstrate the ability to enhance the antioxidant content of crops by introduction of an enzyme that redirects metabolic flux.

Inequalities in breast cancer reconstructive surgery according to social and locational status in Western Australia

AIMS

To study the effects of demographic, locational and social status and the possession of private health insurance in Western Australia on the likelihood of women receiving breast reconstructive surgery after surgery for breast cancer.

METHODS

The WA Record Linkage Project was used to extract all hospital morbidity, cancer and death records of women with breast cancer in Western Australia from 1982 to 2001. Comparisons between those receiving and not receiving breast reconstructive surgery were made after adjustment for co-variates in Cox regression.

RESULTS

Overall, 9.1% of women received breast reconstructive surgery after surgery for breast cancer. Women who were younger, with less co-morbidity and non-indigenous women were more likely to receive breast reconstructive surgery. Women in lower socio-economic groups were much significantly less likely to receive breast reconstructive surgery (RR 0.76; 95% CI 0.54-1.06). Women from rural areas were less likely to receive breast reconstructive surgery than those from metropolitan areas (RR 0.54; 95% CI 0.25-1.15) as were those treated in a rural hospital (RR 0.78; 95% CI 0.66-0.92). Treatment in a private hospital (RR 1.25; 95% CI 1.10-1.42) or with private health insurance (RR 1.25; 95% CI 1.08-1.39) independently increased the likelihood of breast reconstructive surgery.

CONCLUSION

The rate of breast reconstructive surgery was lower than expected with several factors found to affect the rate; women from disadvantaged backgrounds were less likely to receive breast reconstructive surgery than those from more privileged groups.

Centromere satellites from Arabidopsis populations: maintenance of conserved and variable domains

The rapid evolution of centromere sequences between species has led to a debate over whether centromere activity is sequence-dependent. The Arabidopsis thaliana centromere regions contain approximately 20,000 copies of a 178-bp satellite repeat. Here, we analyzed satellites from 41 Arabidopsis ecotypes, providing the first broad population survey of satellite variation within a species. We found highly conserved segments and consistent sequence lengths in the Arabidopsis satellites and in the published collection of human alpha-satellites, supporting models for a functional role. Despite this conservation, polymorphisms are significantly enriched at some sites, yielding variation that could restrict binding proteins to a subset of repeat monomers. Some satellite regions vary considerably; at certain bases, consensus sequences derived from each ecotype diverge significantly from the Arabidopsis consensus, indicating substitutions sweep through a genome in less than 5 million years. Such rapid changes generate more variation within the set of Arabidopsis satellites than in genes from the chromosome arms or from the recombinationally suppressed centromere regions. These studies highlight a balance between the mechanisms that maintain particular satellite domains and the forces that disperse sequence changes throughout the satellite repeats in the genome.

Auditory temporal gap detection for noise markers with partially overlapping and non-overlapping spectra

Temporal gap detection thresholds were obtained from six listeners using an adaptive tracking method and constant spectrum-level noises. In separate blocks of trials, the markers bounding the gap were systematically varied in their spectral overlap or separation (expressed in equivalent rectangular bandwidths, ERBs). In the same listeners, gap thresholds were also obtained for noises of the same bandwidths as those constituting the overlap in the overlap conditions (in the presence of a wideband notched noise masker: 'mask' conditions). For the spectral overlap/separation conditions, gap thresholds were a systematic, linear function of spectral dissimilarity in four of six listeners. In the mask conditions, gap thresholds were inversely related to bandwidth in all listeners. For the three-, four- and five-ERB conditions, gap thresholds in the same listeners for the spectral overlap conditions were higher than those for mask stimuli with the same available within-channel bandwidth and spectrum levels. These data suggest that the spectral dissimilarity between the markers over-rode the availability of within-channel information in the recovery of the temporal gap.

Central auditory onset responses, and temporal asymmetries in auditory perception

Historically, central auditory responses have been studied for their sensitivity to various parameters of tone and noise burst stimulation, with response rate plotted as a function of the stimulus variable. The responses themselves are often quite brief, and locked in time to stimulus onset. In the stimulus amplitude domain, it has recently become clear that these responses are actually driven by properties of the stimulus' onset transient, and this has had important implications for how we interpret responses to manipulations of tone (or noise) burst plateau level. That finding was important in its own right, but a more general scrutiny of the available neurophysiological and psychophysical evidence reveals that there is a significant asymmetry in the neurophysiological and perceptual processing of stimulus onsets and offsets: sound onsets have a more elaborate neurophysiological representation, and receive a greater perceptual weighting. Hypotheses about origins of the asymmetries, derived independently from psychophysics and from neurophysiology, have in common a response threshold mechanism which adaptively tracks the ongoing level of stimulation.

Transgenic production of epoxy fatty acids by expression of a cytochrome P450 enzyme from Euphorbia lagascae seed

Seed oils of a number of Asteraceae and Euphorbiaceae species are enriched in 12-epoxyoctadeca-cis-9-enoic acid (vernolic acid), an unusual 18-carbon Delta(12)-epoxy fatty acid with potential industrial value. It has been previously demonstrated that the epoxy group of vernolic acid is synthesized by the activity of a Delta(12)-oleic acid desaturase-like enzyme in seeds of the Asteraceae Crepis palaestina and Vernonia galamensis. In contrast, results from metabolic studies have suggested the involvement of a cytochrome P450 enzyme in vernolic acid synthesis in seeds of the Euphorbiaceae species Euphorbia lagascae. To clarify the biosynthetic origin of vernolic acid in E. lagascae seed, an expressed sequence tag analysis was conducted. Among 1,006 randomly sequenced cDNAs from developing E. lagascae seeds, two identical expressed sequence tags were identified that encode a cytochrome P450 enzyme classified as CYP726A1. Consistent with the seed-specific occurrence of vernolic acid in E. lagascae, mRNA corresponding to the CYP726A1 gene was abundant in developing seeds, but was not detected in leaves. In addition, expression of the E. lagascae CYP726A1 cDNA in Saccharomyces cerevisiae was accompanied by production of vernolic acid in cultures supplied with linoleic acid and an epoxy fatty acid tentatively identified as 12-epoxyoctadeca-9,15-dienoic acid (12-epoxy-18:2Delta(9,15)) in cultures supplied with alpha-linolenic acid. Consistent with this, expression of CYP726A1 in transgenic tobacco (Nicotiana tabacum) callus or somatic soybean (Glycine max) embryos resulted in the accumulation of vernolic acid and 12-epoxy-18:2Delta(9,15). Overall, these results conclusively demonstrate that Asteraceae species and the Euphorbiaceae E. lagascae have evolved structurally unrelated enzymes to generate the Delta(12)-epoxy group of vernolic acid.

Outcomes measurement for asthma following acute presentation to an emergency department

The Asthma Management Plan (AMP) was developed by the Thoracic Society of Australia and New Zealand in 1989 to provide a more uniform approach to asthma care, aimed at reducing mortality, morbidity and emergency presentations. The AMP is often supplemented with Asthma Clinical Pathways (CPs) within the emergency department and hospital setting. This study was designed to evaluate the impact of these two instruments on asthma outcomes one month after presentation to the emergency department. The AMP and CP were both found to have had positive influences on asthma management. However, the study illustrates that there continue to be problems with asthma management, which would be improved by a more consistent use of these instruments.

A chromosomal region promoting outcrossing in a conifer

Prefertilization mechanisms influencing selfing rates are thought to be absent in conifers. Outcrossing in conifers is promoted via an embryo-lethal system, but the genetic mechanism is poorly understood. This study is the first experimental profile of the genetic mechanism promoting outcrossing in conifers. Molecular dissection of a Pinus taeda L. selfed pedigree detected a chromosomal region identified as PtTX3020-RPtest9. Within this region, a semilethal factor was tightly linked (r = 0.0076) to a polymorphic expressed sequence tag (EST). The linkage group flanking the lethal factor showed strong heterozygote advantage. Using genotypic frequencies for the linkage group, three hypotheses about the semilethal factor could be tested: (1) the presence of a balanced lethal system, i.e., a lethal factor present in each of the two marker intervals; (2) gametic selection operative prior to fertilization; and (3) a stage-specific lethal factor. Selection acted via the embryo-lethal system. No support for a genetic mechanism operating prior to fertilization was found. The semilethal factor exerted no effect after embryo maturity. The genetic mechanism promoting outcrossing in P. taeda L. appears to have a balancing selection system due to either pseudo-overdominance or true overdominance.

Spatial and temporal factors in auditory saltation

This report describes three experiments on auditory saltation, studied with click stimuli presented at interclick intervals (ICIs) from 30 to 240 ms. In experiment 1, subjects rated the strength of the saltation illusion evoked by trains of six monaural clicks (i.e., three presented to one ear followed by three to the other ear), and six dichotic clicks on which were imposed either a 500-micros interaural time difference or a 9-dB interaural level difference (ILD). The interaural disparity of theclicks was reversed at the midpoint of the train. Subjects reported equivalent strengths of saltation for the dichotic clicks, but weaker saltation for the monaural ones. These data indicated that saltation is supported by dichotic clicks, regardless of the stimulus manipulation used to generate the lateralized images. In experiment 2, subjects rated the strength of the saltation evoked by six click trains lateralized, in separate trials, by ILDs ranging from 9 to 30 dB, and by a train of monaural clicks. In all ILD conditions, the level of the clicks at the "quiet" ear was above click-detection threshold when presented monaurally. Saltation weakened with increasing ILD, and approximated that seen with monaural clicks when the ILD was 30 dB. These data indicated that for the range of ICIs used here, saltation weakened as the stimuli became more strongly lateralized. In experiment 3, the number of dichotic clicks preceding the disparity reversal was, in separate trials, varied from 3 to 10, and subjects were asked to detect the presence of spatial stationarity in the click train. By plotting the subjective ratings as a function of the length of the leading click train, it was shown that the temporal window within which the saltation effect operates varies between listeners, but is usually less than about 350-400 ms.

Cortisol levels predict cognitive impairment induced by electroconvulsive therapy

BACKGROUND

Elevated glucocorticoids may increase the vulnerability of the brain to the adverse effects of repeated seizures. This study tested the hypothesis that higher ambient cortisol levels would predict increased cognitive impairment in depressed patients subsequent to receiving electroconvulsive therapy (ECT) for major depression.

METHODS

Sixteen subjects provided three samples of saliva the day before receiving unilateral nondominant ECT. Measures of mood, global cognitive functioning, attention, executive function, verbal and visuospatial memory, and visuospatial processing speed were obtained 1 day before the first ECT and 1 day after the sixth ECT treatment. The relationship between basal salivary cortisol obtained before the first ECT treatment and the change score of each cognitive measure after the sixth ECT treatment was examined and tested with Pearson correlation coefficients.

RESULTS

Electroconvulsive therapy treatments delivered over 2 weeks resulted in a significant improvement in mood and a decline in most measures of cognitive performance. Elevated basal cortisol was associated with a greater decline in performance of executive function, visuospatial processing speed, and verbal memory.

CONCLUSIONS

Although this study is limited by the small number of subjects and the high number of comparisons, all significant correlations were consistent with the hypothesis that elevated cortisol predicts a greater degree of ECT-induced cognitive impairment.

Cytotoxic T-cell abundance and virus load in human immunodeficiency virus type 1 and human T-cell leukaemia virus type 1

The correlation between virus load and specific cytotoxic T-lymphocyte (CTL) frequency during the chronic phase in human immunodeficiency virus type 1 (HIV-1) infection has been found to be negative in cross-sectional studies. We report here that, in infection with the related retrovirus human T-cell leukaemia virus type 1 (HTLV-1), the correlation is positive in asymptomatic carriers and zero in patients with the associated inflammatory disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We demonstrate that the direction of the correlation may depend on the efficacy of the CTL response using mathematical models. We conclude that the CTL response is effective in asymptomatic carriers of HTLV-1, but ineffective in patients with HAM/TSP. Virus-mediated impairment of specific CTL production in HIV-1 infection can account for the negative correlation observed.

Sensitivity of unanesthetized chinchilla auditory system to noise burst onset, and the effects of carboplatin

The gross near-field responses of the auditory nerve and inferior colliculus to noise burst stimuli were recorded through intracranially implanted electrodes in six unanesthetized chinchillas. Responses were studied as a function of stimulus plateau amplitude and rise time, both before and after a systemic dose of 75 mg/kg of carboplatin. Both recording sites showed sensitivity to stimulus level and rise time. Increases in stimulus level and decreases in stimulus rise time each produced increases in the response magnitude, and decreases in response latency. When the stimuli were re-specified as rate of pressure change at sound onset (Pa/s), the amplitude and latency of responses at each site were found to be a direct function of rate of sound pressure change. These data provide the first confirmation in unanesthetized animals of previous single unit observations in barbiturate-anesthetized cats. Carboplatin treatment resulted in a 20-80% loss of inner hair cells, a modest threshold elevation, and a 50-75% reduction in peak response amplitudes. The general patterns of sensitivity to stimulus level and rise time were not markedly affected by carboplatin, nor was the fashion in which response parameters (amplitude and latency) were ruled by rate of pressure change at sound onset.

Formation of conjugated delta8,delta10-double bonds by delta12-oleic-acid desaturase-related enzymes: biosynthetic origin of calendic acid

Divergent forms of the plant Delta(12)-oleic-acid desaturase (FAD2) have previously been shown to catalyze the formation of acetylenic bonds, epoxy groups, and conjugated Delta(11),Delta(13)-double bonds by modification of an existing Delta(12)-double bond in C(18) fatty acids. Here, we report a class of FAD2-related enzymes that modifies a Delta(9)-double bond to produce the conjugated trans-Delta(8),trans-Delta(10)-double bonds found in calendic acid (18:3Delta(8trans,10trans,12cis)), the major component of the seed oil of Calendula officinalis. Using an expressed sequence tag approach, cDNAs for two closely related FAD2-like enzymes, designated CoFADX-1 and CoFADX-2, were identified from a C. officinalis developing seed cDNA library. The deduced amino acid sequences of these polypeptides share 40-50% identity with those of other FAD2 and FAD2-related enzymes. Expression of either CoFADX-1 or CoFADX-2 in somatic soybean embryos resulted in the production of calendic acid. In embryos expressing CoFADX-2, calendic acid accumulated to as high as 22% (w/w) of the total fatty acids. In addition, expression of CoFADX-1 and CoFADX-2 in Saccharomyces cerevisiae was accompanied by calendic acid accumulation when induced cells were supplied exogenous linoleic acid (18:2Delta(9cis,12cis)). These results are thus consistent with a route of calendic acid synthesis involving modification of the Delta(9)-double bond of linoleic acid. Regiospecificity for Delta(9)-double bonds is unprecedented among FAD2-related enzymes and further expands the functional diversity found in this family of enzymes.

Independence of frequency channels in auditory temporal gap detection

The ability of listeners to detect a temporal gap in a 1600-Hz-wide noiseband (target) was studied as a function of the absence and presence of concurrent stimulation by a second 1600-Hz-wide noiseband (distractor) with a nonoverlapping spectrum. Gap detection thresholds for single noisebands centered on 1.0, 2.0, 4.0, and 5.0 kHz were in the range from 4 to 6 ms, and were comparable to those described in previous studies. Gap thresholds for the same target noisebands were only modestly improved by the presence of a synchronously gated gap in a second frequency band. Gap thresholds were unaffected by the presence of a continuous distractor that was either proximate or remote from the target frequency band. Gap thresholds for the target noiseband were elevated if the distractor noiseband also contained a gap which "roved" in time in temporal proximity to the target gap. This effect was most marked in inexperienced listeners. Between-channel gap thresholds, obtained using leading and trailing markers that differed in frequency, were high in all listeners, again consistent with previous findings. The data are discussed in terms of the levels of the auditory perceptual processing stream at which the listener can voluntarily access auditory events in distinct frequency channels.

Solid-phase synthesis of 1,2,3, 4-tetrahydro-beta-carboline-containing peptidomimetics

A solid-phase method for the synthesis of 1,2,3, 4-tetrahydro-beta-carboline-containing peptidomimetics has been developed. The key step in the strategy is the Pictet-Spengler condensation of a resin-bound tryptophan-containing fragment with an Fmoc-amino aldehyde.

Production of fatty acid components of meadowfoam oil in somatic soybean embryos

The seed oil of meadowfoam (Limnanthes alba) and other Limnanthes spp. is enriched in the unusual fatty acid Delta(5)-eicosenoic acid (20:1Delta(5)). This fatty acid has physical and chemical properties that make the seed oil of these plants useful for a number of industrial applications. An expressed sequence tag approach was used to identify cDNAs for enzymes involved in the biosynthesis of 20:1Delta(5)). By random sequencing of a library prepared from developing Limnanthes douglasii seeds, a class of cDNAs was identified that encode a homolog of acyl-coenzyme A (CoA) desaturases found in animals, fungi, and cyanobacteria. Expression of a cDNA for the L. douglasii acyl-CoA desaturase homolog in somatic soybean (Glycine max) embryos behind a strong seed-specific promoter resulted in the accumulation of Delta(5)-hexadecenoic acid to amounts of 2% to 3% (w/w) of the total fatty acids of single embryos. Delta(5)-Octadecenoic acid and 20:1Delta(5) also composed <1% (w/w) each of the total fatty acids of these embryos. In addition, cDNAs were identified from the L. douglasii expressed sequence tags that encode a homolog of fatty acid elongase 1 (FAE1), a beta-ketoacyl-CoA synthase that catalyzes the initial step of very long-chain fatty acid synthesis. Expression of the L. douglassi FAE1 homolog in somatic soybean embryos was accompanied by the accumulation of C(20) and C(22) fatty acids, principally as eicosanoic acid, to amounts of 18% (w/w) of the total fatty acids of single embryos. To partially reconstruct the biosynthetic pathway of 20:1Delta(5) in transgenic plant tissues, cDNAs for the L. douglasii acyl-CoA desaturase and FAE1 were co-expressed in somatic soybean embryos. In the resulting transgenic embryos, 20:1Delta(5) and Delta(5)-docosenoic acid composed up to 12% of the total fatty acids.

D-Ala-D-X ligases: evaluation of D-alanyl phosphate intermediate by MIX, PIX and rapid quench studies

BACKGROUND

The D-alanyl-D-lactate (D-Ala-D-Lac) ligase is required for synthesis of altered peptidoglycan (PG) termini in the VanA phenotype of vancomycin-resistant enterococci (VRE), and the D-alanyl-D-serine (D-Ala-D-Ser) ligase is required for the VanC phenotype of VRE. Here we have compared these with the Escherichia coli D-Ala-D-Ala ligase DdlB for formation of the enzyme-bound D-alanyl phosphate, D-Ala(1)-PO(3)(2-) (D-Ala(1)-P), intermediate.

RESULTS

The VanC2 ligase catalyzes a molecular isotope exchange (MIX) partial reaction, incorporating radioactivity from (14)C-D-Ser into D-Ala-(14)C-D-Ser at a rate of 0.7 min(-1), which approaches kinetic competence for the reversible D-Ala(1)-P formation from the back direction. A positional isotope exchange (PIX) study with the VanC2 and VanA ligases displayed a D-Ala(1)-dependent bridge to nonbridge exchange of the oxygen-18 label of [gamma-(18)O(4)]-ATP at rates of up to 0.6 min(-1); this exchange was completely suppressed by the addition of the second substrate D-Ser or D-Lac, respectively, as the D-Ala(1)-P intermediate was swept in the forward direction. As a third criterion for formation of bound D-Ala(1)-P, we conducted rapid quench studies to detect bursts of ADP formation in the first turnover of DdlB and VanA. With E. coli DdlB, there was a burst amplitude of ADP corresponding to 26-30% of the DdlB active sites, followed by the expected steady-state rate of 620-650 min(-1). For D-Ala-D-Lac and D-Ala-D-Ala synthesis by VanA, we measured a burst of 25-30% or 51% of active enzyme, respectively.

CONCLUSIONS

These three approaches support the rapid (more than 1000 min(-1)), reversible formation of the enzyme intermediate D-Ala(1)-P by members of the D-Ala-D-X (where X is Ala, Ser or Lac) ligase superfamily.

Low-copy microsatellite markers for Pinus taeda L

Eighteen low-copy and genomic microsatellite markers were tested for Mendelian inheritance and then assayed in 41 Pinus taeda L. samples drawn from five regions in the southern United States. The PCR products had multiple alleles, high levels of polymorphism, and little non-specific priming. Fifteen of the 18 markers were informative for a P. taeda three-generation RFLP (restriction fragment length polymorphism) pedigree, and a P. taeda population survey revealed three to 28 alleles per locus. The highest allele numbers and polymorphic information content (PIC) values were associated with complex repeat sequences and (or) with sequences consisting of the longer strings of perfect repeats. The abundance of low- to rare-frequency alleles also accounted for high PIC values in both types of markers. Low-copy microsatellites are useful for the large, complex pine genome, especially in the absence of entire gene sequences in public databases and with the low levels of polymorphism in markers developed from expressed sequence tags (ESTs).

Low-copy microsatellite markers for Pinus taeda L

Eighteen low-copy and genomic microsatellite markers were tested for Mendelian inheritance and then assayed in 41 Pinus taeda L. samples drawn from five regions in the southern United States. The PCR products had multiple alleles, high levels of polymorphism, and little non-specific priming. Fifteen of the 18 markers were informative for a P. taeda three-generation RFLP (restriction fragment length polymorphism) pedigree, and a P. taeda population survey revealed three to 28 alleles per locus. The highest allele numbers and polymorphic information content (PIC) values were associated with complex repeat sequences and (or) with sequences consisting of the longer strings of perfect repeats. The abundance of low- to rare-frequency alleles also accounted for high PIC values in both types of markers. Low-copy microsatellites are useful for the large, complex pine genome, especially in the absence of entire gene sequences in public databases and with the low levels of polymorphism in markers developed from expressed sequence tags (ESTs).Key words: loblolly pine, conifers, gymnosperms, trinucleotide repeat motifs.

Hip fracture outcomes: quality of life and functional status in older adults living in the community

BACKGROUND

People who return to living in the community after a hip fracture are considered to have the best outcome. However, their quality of life (QOL) and its relationship with function over the longer term have not been fully assessed.

AIMS

This case control study of community dwelling subjects six to 12 months post hip fracture aims to investigate their QOL and functional independence.

METHOD

The Short Form-36 (SF-36) was utilised to measure QOL. The Modified Barthel Index (MBI), the Frenchay Activities of Daily Living Index (FAI), the Timed 'Up & Go' (TUG), and the Berg Balance Scale (Berg) were used to measure functionality.

RESULTS

Ninety-two subjects and 92 controls were recruited. Despite being age and gender matched, the hip fracture subjects scored significantly (p<0.05) worse than the controls in all measures of function. The fracture group was slower on the TUG (19 vs 10.5 seconds), had more difficulties with balance (46 vs 54 out of 56), and was less active and more dependent than the control group (FAI 24 vs 31 out of 42). The SF-36 has eight domains: physical function, role physical, bodily pain, mental health, role emotional, social function, general health and vitality. The control group had a higher (p<0.05) perception of their QOL in all domains.

CONCLUSION

The effects of impaired balance and mobility along with reduced functional and social independence are reflected in the diminished QOL perceived by the fracture group. This indicates that many do not return to their pre-fracture lifestyle.

1,2-Dibenzamidobenzene inhibitors of human factor Xa

High-throughput screening of a combinatorial library of diamidophenols yielded lead compounds with the ability to inhibit human factor Xa (fXa) at micromolar concentrations (e.g. compound 4, fXa apparent K(ass) = 0.64 x 10(6) L/mol). SAR studies in this novel structural series of fXa inhibitors showed that the phenolic hydroxyl group was not essential for activity. The best activity was found in substituted 1,2-dibenzamidobenzenes in which the phenyl group of one benzoyl group (A-ring) was substituted in the 4-position with relatively small lipophilic or polarizable groups such as methoxy, vinyl, or chloro and the phenyl group of the other benzoyl group (B-ring) was substituted in the 4-position with larger lipophilic groups such as tert-butyl or dimethylamino. The central phenyl ring (C-ring) tolerated a wide variety of substituents, but methoxy, methanesulfonamido, hydroxyl, and carboxyl substitution produced slightly higher levels of activity than other substituents when present in combination with favorable B-ring substitution. Methylation of the amide nitrogen atoms was found to greatly decrease activity. Compound 12 is the highest affinity fXa inhibitor in this group of compounds, having fXa apparent K(ass) = 25.5 x 10(6) L/mol, about 40x more active than the original lead. This lead series does not show potent inhibition of human thrombin. A model for the binding of these ligands to the fXa active site is proposed. The model is consistent with the observed SAR and can serve to guide future SAR studies.

Effect of lamivudine on human T-cell leukemia virus type 1 (HTLV-1) DNA copy number, T-cell phenotype, and anti-tax cytotoxic T-cell frequency in patients with HTLV-1-associated myelopathy

Patients with human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) typically have a high HTLV-1 proviral load in peripheral blood mononuclear cells and abundant, activated HTLV-1-specific cytotoxic T lymphocytes (CTLs). No effective treatment for HAM/TSP has been described so far. We report a 10-fold reduction in viral DNA for five patients with HAM/TSP during treatment with the reverse transcriptase inhibitor lamivudine. In one patient with recent-onset HAM/TSP, the reduction in viral DNA was associated with a fall in the frequency of CTLs specific to two peptides in the immunodominant viral antigen Tax. The half-life of peripheral blood mononuclear cell populations was estimated from changes in viral DNA copy number, CTL frequency, reduction in CD25 expression, and the loss of dicentric chromosomes following radiation-induced damage. Each of these four different techniques indicated a cellular half-life of approximately 3 days consistent with continuous lymphocyte replication and destruction. These results indicate that viral replication through reverse transcription significantly contributes to the maintenance of HTLV-1 viral DNA load. The relative contribution of proliferation versus replication may vary between infected people.

Dealing with the anger and hostility of those who grieve

Hospice caregivers are often targets of appropriate or displaced anger from the patients and family members that they try to help. Although anger is often an essential part of the grieving process, it may be difficult to endure. Caregivers must therefore understand the causes and signs of anger in themselves, patients, and family members, and find strategies to reduce the anger. A therapeutic response to anger will better facilitate the grief process as well as the effectiveness and well-being of the hospice caregiver.