Important Foundation (important + foundation)

Distribution by Scientific Domains


Selected Abstracts


MicroRNA expression during chick embryo development

DEVELOPMENTAL DYNAMICS, Issue 11 2006
Diana K. Darnell
Abstract MicroRNAs (miRNAs) are small, abundant, noncoding RNAs that modulate protein abundance by interfering with target mRNA translation or stability. miRNAs are detected in organisms from all domains and may regulate 30% of transcripts in vertebrates. Understanding miRNA function requires a detailed determination of expression, yet this has not been reported in an amniote species. High-throughput whole mount in situ hybridization was performed on chicken embryos to map expression of 135 miRNA genes including five miRNAs that had not been previously reported in chicken. Eighty-four miRNAs were detected before day 5 of embryogenesis, and 75 miRNAs showed differential expression. Whereas few miRNAs were expressed during formation of the primary germ layers, the number of miRNAs detected increased rapidly during organogenesis. Patterns highlighted cell-type, organ or structure-specific expression, localization within germ layers and their derivatives, and expression in multiple cell and tissue types and within sub-regions of structures and tissues. A novel group of miRNAs was highly expressed in most tissues but much reduced in one or a few organs, including the heart. This study presents the first comprehensive overview of miRNA expression in an amniote organism and provides an important foundation for investigations of miRNA gene regulation and function. Developmental Dynamics 235:3156,3165, 2006. © 2006 Wiley-Liss, Inc. [source]


Special considerations for haematology patients in relation to end-of-life care: Australian findings

EUROPEAN JOURNAL OF CANCER CARE, Issue 2 2007
P. MCGRATH bsocwk, senior research fellow
Recent haematology clinical guidelines recommend that palliative care specialists should have central roles in haemato-oncology teams. However, the available research evidence indicates there are presently significant obstacles to the integration of palliative care in haematology. The following discussion presents findings from an Australian study designed to address the problems associated with lack of referral of haematology patients to the palliative system through the development of a best-practice model for end-of-life care for these diagnostic groups. The preliminary step in the development of such a model is to document the factors that denote the special characteristics of the end-of-life stage of haematological conditions and their treatments. This article presents the list of special considerations from a nursing perspective, including issues associated with the high-tech nature of treatments, the speed of change to a terminal event, the need for blood products and possibility of catastrophic bleeds, the therapeutic optimism based on a myriad of treatment options and the clinical indices of the terminal trajectory. The nursing insights provide an important foundation for building a practical, patient-centred model for terminal care in haematology. [source]


Pemphigus mouse model as a tool to evaluate various immunosuppressive therapies

EXPERIMENTAL DERMATOLOGY, Issue 3 2009
Yujiro Takae
Abstract:, Pemphigus vulgaris (PV) is an autoimmune bullous disease caused by immunoglobulin G (IgG) autoantibodies against desmoglein 3 (Dsg3). We have generated an active disease mouse model for PV by adoptive transfer of Dsg3,/, lymphocytes. In this study, we investigated the benefits and limitations of this model as a tool to evaluate various immunosuppressive therapeutic strategies. We used the following three measurements to evaluate the effects of the drugs during the time course: Dsg3 enzyme-linked immunosorbent assay scores that represent the level of production of anti-Dsg3 IgG, body weight loss that reflects the severity of oral erosions and PV score that reflects the extent of skin lesions. We examined various immunosuppressive agents currently used to treat patients with PV model mice in preventive protocol. Cyclophosphamide almost completely suppressed the production of anti-Dsg3 IgG, development of body weight loss and the appearance of the PV phenotype in contrast with the control group without the drug. Azathioprine, cyclosporin A and tacrolimus hydrate also showed suppressive effects to various degrees. However, methylprednisolone and dexamethasone failed to show significant effects in contrast to the findings reported in humans. Knowing the advantages and limitations of this model will provide an important foundation for the future evaluation and development of novel therapeutic strategies. [source]


Reconciling plant strategy theories of Grime and Tilman

JOURNAL OF ECOLOGY, Issue 6 2005
JOSEPH M. CRAINE
Summary 1The theories of Grime and Tilman are ambitious attempts to unify disparate theories regarding the construction of plants, their interaction with the environment and the assembly of communities. After over two decades of parallel research, their ideas have not been reconciled, hindering progress in understanding the functioning of ecosystems. 2Grime's theories do not adequately incorporate the importance of non-heterogeneous supplies of nutrients and how these supplies are partitioned over long time scales, are inconsistent regarding the importance of disturbance in nutrient-limited habitats and need to reconsider the carbon economy of shade-tolerant plants. 3Failure to account for differences between aquatic and terrestrial systems in how resource supplies are partitioned led Tilman to develop a shifting set of theories that have become reduced in mechanistic detail over time. The most recent highlighted the reduction of nutrient concentrations in soil solution, although it can no longer be derived from any viable mechanistic model. The slow diffusion of nutrients in soils means that the reduction of average soil solution nutrient concentrations cannot explain competitive exclusion. 4Although neither theory, nor a union of the two, adequately characterizes the dynamics of terrestrial plant assemblages, the complementarity in their assumptions serve as an important foundation for future theory and research. 5Reconciling the approaches of Grime and Tilman leads to six scenarios for competition for nutrients and light, with the outcome of each depending on the ability of plants to pre-empt supplies. Under uniform supplies, pulses or patches, light competition requires leaf area dominance, while nutrient competition requires root length dominance. There are still important basic questions regarding the nature of nutrient supplies that will need to be answered, but recent research brings us closer to a unified set of theories on resource competition. [source]


Global epidemiology of HIV,

JOURNAL OF MEDICAL VIROLOGY, Issue S1 2006
Francine E. McCutchan
Abstract HIV is among the most generically variable of human pathogens. A comprehensive and detailed description of HIV strains in the pandemic is an important foundation for diagnosis, treatment, and prevention. The current sequence database for HIV includes almost 800 complete genome sequences, documenting HIV-1 groups M, O, and N, and HIV-2. Among HIV-1 group M strains, responsible for the vast majority of HIV infections worldwide, 743 sequences represent 9 genetic subtypes, 16 circulating recombinant forms (CRF) that are spreading in populations, and a variety of unique recombinant forms (URF), identified so far only from a single individual. The global distribution of HIV is complex and dynamic with regional epidemics harboring only a subset of the global diversity. HIV strains differ enormously in terms of global prevalence. Six strains account for the majority of HIV infections: HIV-1 subtypes A, B, C, D, and two of the CRF, CRF01-AE and CRF02_AG, respectively. Many of the known subtypes and recombinant forms are currently rare in the epidemic, but could spread more widely if favorable conditions arise. HIV-2 is largely restricted to West Africa at relatively low prevalence there. Groups O and N of HIV-1 are very rare in the pandemic. The goal of universal coverage of HIV-1 strains by diagnostic tests can be met by minimizing false negative test rates for the six globally prevalent HIV-1 group M strains and HIV-2, and by evaluating systematically coverage of rare subtypes and recombinant forms. J. Med. Virol. 78:S7,S12, 2006. © 2006 Wiley-Liss, Inc. [source]


Physical Health and Drinking Among Medical Inpatients With Unhealthy Alcohol Use: A Prospective Study,

ALCOHOLISM, Issue 7 2010
Emily C. Williams
Objective:, Unhealthy alcohol use is common in medical inpatients, and hospitalization has been hypothesized to serve as a "teachable moment" that could motivate patients to decrease drinking, but studies of hospital-based brief interventions have often not found decreases. Evaluating associations between physical health and subsequent drinking among medical inpatients with unhealthy alcohol use could inform refinement of hospital-based brief interventions by identifying an important foundation on which to build them. We tested associations between poor physical health and drinking after hospitalization and whether associations varied by alcohol dependence status and readiness to change. Methods:, Participants were medical inpatients who screened positive for unhealthy alcohol use and consented to participate in a randomized trial of brief intervention (n = 341). Five measures of physical health were independent variables. Outcomes were abstinence and the number of heavy drinking days (HDDs) reported in the 30 days prior to interviews 3 months after hospitalization. Separate regression models were fit to evaluate each independent variable controlling for age, gender, randomization group, and baseline alcohol use. Interactions between each independent variable and alcohol dependence and readiness to change were tested. Stratified models were fit when significant interactions were identified. Results:, Among all participants, measures of physical health were not significantly associated with either abstinence or number of HDDs at 3 months. Having an alcohol-attributable principal admitting diagnosis was significantly associated with fewer HDDs in patients who were nondependent [adjusted incidence rate ratio (aIRR) 0.10, 95% CI 0.03,0.32] or who had low alcohol problem perception (aIRR 0.36, 95% CI 0.13,0.99) at hospital admission. No significant association between alcohol-attributable principal admitting diagnosis and number of HDDs was identified for participants with alcohol dependence or high problem perception. Conclusions:, Among medical inpatients with nondependent unhealthy alcohol use and those who do not view their drinking as problematic, alcohol-attributable illness may catalyze decreased drinking. Brief interventions that highlight alcohol-related illness might be more successful. [source]


Generation of human embryonic stem cell-derived mesoderm and cardiac cells using size-specified aggregates in an oxygen-controlled bioreactor

BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2009
Sylvia Niebruegge
Abstract The ability to generate human pluripotent stem cell-derived cell types at sufficiently high numbers and in a reproducible manner is fundamental for clinical and biopharmaceutical applications. Current experimental methods for the differentiation of pluripotent cells such as human embryonic stem cells (hESC) rely on the generation of heterogeneous aggregates of cells, also called "embryoid bodies" (EBs), in small scale static culture. These protocols are typically (1) not scalable, (2) result in a wide range of EB sizes and (3) expose cells to fluctuations in physicochemical parameters. With the goal of establishing a robust bioprocess we first screened different scalable suspension systems for their ability to support the growth and differentiation of hESCs. Next homogeneity of initial cell aggregates was improved by employing a micro-printing strategy to generate large numbers of size-specified hESC aggregates. Finally, these technologies were integrated into a fully controlled bioreactor system and the impact of oxygen concentration was investigated. Our results demonstrate the beneficial effects of stirred bioreactor culture, aggregate size-control and hypoxia (4% oxygen tension) on both cell growth and cell differentiation towards cardiomyocytes. QRT-PCR data for markers such as Brachyury, LIM domain homeobox gene Isl-1, Troponin T and Myosin Light Chain 2v, as well as immunohistochemistry and functional analysis by response to chronotropic agents, documented the impact of these parameters on cardiac differentiation. This study provides an important foundation towards the robust generation of clinically relevant numbers of hESC derived cells. Biotechnol. Bioeng. 2009;102: 493,507. © 2008 Wiley Periodicals, Inc. [source]