bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of Epha4 enhancer required for segmental expression and the regulation by Mesp2
Authors: Nakajima Yoshiro , Morimoto Mitsuru , Takahashi Yuki , Koseki Haruhiko , Saga Yumiko
Published: May 2006

Somites provide the basic body plan for metameric axial structures in vertebrates, and establish the segmental features through the sequential gene expression in the presomitic mesoderm (PSM). A crucial protein for segment border formation is the bHLH transcription factor Mesp2, the expression of which is restricted to the anterior PSM. A gene candidate that is activated by Mesp2 is Epha4, as its expression pattern resembles Mesp2and is absent in Mesp2-null embryos. We have analyzed the enhancer region of Epha4, which is responsible for its expression in the anterior PSM,and identified an E-box containing region. Subsequent transgenic and transient luciferase analyses successfully determined that the presence of repeated E-box sequences is a minimum essential requirement for the expression in the anterior PSM. We also show that Mesp2 directly binds to the enhancer sequence of Epha4. Furthermore, the forced expression of Mesp2 in somitic cells results in the activation of Epha4 and repression of the caudal gene Uncx4.1, which may trigger the events leading to the formation of abnormal somites and rostralized vertebra. In addition, ectopic Mesp2 expression induces abnormally epithelialized structures, which support to the idea that Mesp2 induces the formation of segmental borders by activating genes that play roles in cellular epithelialization.
αA-crystallin expression prevents γ-crystallin insolubility and cataract formation in the zebrafishclochemutant lens
Authors: Goishi Katsutoshi , Shimizu Akio , Najarro Gabriel , Watanabe Sumiko , Rogers Rick , Zon Leonard I. , Klagsbrun Michael
Published: May 2006

Cataracts, the loss of lens transparency, are the leading cause of human blindness. The zebrafish embryo, with its transparency and relatively large eyes, is an excellent model for studying ocular disease in vivo. We found that the zebrafish cloche mutant, both the clochem39and clocheS5 alleles, which have defects in hematopoiesis and blood vessel development, also have lens cataracts. Quantitative examination of the living zebrafish lens by confocal microscopy showed significant increases in lens reflectance. Histological analysis revealed retention of lens fiber cell nuclei owing to impeded terminal differentiation. Proteomics identified γ-crystallin as a protein that was substantially diminished in cloche mutants. Crystallins are the major structural proteins in mouse, human and zebrafish lens. Defects in crystallins have previously been shown in mice and humans to contribute to cataracts. The loss of γ-crystallin protein in cloche was not due to lowered mRNA levels but rather to γ-crystallin protein insolubility.αA-crystallin is a chaperone that protects proteins from misfolding and becoming insoluble. The cloche lens is deficient in bothαA-crystallin mRNA and protein during development from 2-5 dpf. Overexpression of exogenous αA-crystallin rescued the cloche lens phenotype, including solubilization ofγ-crystallin, increased lens transparency and induction of lens fiber cell differentiation. Taken together, these results indicate thatα A-crystallin expression is required for normal lens development and demonstrate that cataract formation can be prevented in vivo. In addition, these results show that proteomics is a valuable tool for detecting protein alterations in zebrafish.
Comparative plasticity of brain synapses in inbred mouse strains
Authors: Nguyen P. V.
Published: May 2006

One niche of experimental biology that has experienced considerable progress is the neurobiology of learning and memory. A key contributor to such progress has been the widespread use of transgenic and `knockout' mice to elucidate the mechanisms of identifiable phenotypes of learning and memory. Inbred mouse strains are needed to generate genetically modified mice. However, genetic variations between inbred strains can confound the interpretation of cellular neurophysiological phenotypes of mutant mice. It is known that altered physiological strength of synaptic transmission (`synaptic plasticity') can modify and regulate learning and memory. Characterization of the synaptic phenotypes of inbred mouse strains is needed to identify the most appropriate strains to use for generating mutant mouse models of memory function. More importantly, comparative electrophysiological analyses of inbred mice per se can also shed light on which forms of synaptic plasticity underlie particular types of learning and memory. Many such analyses have focused on synaptic plasticity in the hippocampus because of the critical roles of this brain structure in the formation and consolidation of long-term memories. Comparative electrophysiological data obtained from several inbred mouse strains are reviewed here to highlight the following key notions: (1) synaptic plasticity is influenced by the genetic backgrounds of inbred mice; (2) the plasticity of hippocampal synapses in inbred mice is`tuned' to particular temporal patterns of activity; (3) long-term potentiation, but not long-term depression, is a cellular correlate of behavioural memory performance in some strains; (4) synaptic phenotyping of inbred mouse strains can identify cellular models of memory impairment that can be used to elucidate mechanisms that may cause specific memory deficits.
Phenotypic plasticity of adult myocardium: molecular mechanisms
Authors: Swynghedauw Bernard
Published: May 2006

Cardiac phenotypic plasticity (so-called cardiac remodelling, CR) is characterized by changes in myocardial structure that happen in response to either mechanical overload or a loss of substance such as that occurring after myocardial infarction.

Mechanosensation is a widespread biological process and is inextricably mixed with other transduction systems from hormones and vasopeptides, which ultimately produce post-translational modifications of transcription factors. The expression of the four main transcription factors during cardiogenesis is also enhanced as a link to foetal reprogramming.

CR results from re-expression of the foetal programme, which is mostly adaptive, but also from several other phenotypic modifications that are not usually adaptive, such as fibrosis. (i) The initial determinant is mechanical,and re-expression of the foetal programme includes a global increase in genetic expression with cardiac hypertrophy, re-expression of genes that are normally not expressed in the adult ventricles, repression of genes not expressed during the foetal life, and activation of pre-exisiting stem cells. Microarray technology has revealed a coordinated change in expression of genes pertaining to signal transduction, metabolic function, structure and motility,and cell organism defence. The physiological consequence is a better adapted muscle. (ii) During clinical conditions, the effects of mechanics are modified by several interfering determinants that modify CR, including senescence,obesity, diabetes, ischemia and the neurohormonal reaction. Each of these factors can alter myocardial gene expression and modify molecular remodelling of mechanical origin.

Finally, as compared to evolutionary phenotypic plasticity described in plants and insects in response to variations in environmental conditions, in CR, the environmental factor is internal, plasticity is primarily adaptive,and it involves coordinated changes in over 1400 genes. Study of reaction norms showed that the genotypes from different animal species are similarly plastic, but there are transgenic models in which adaptation to mechanics is not caused by hypertrophy but by qualitative changes in gene expression.
Neuronal networks and synaptic plasticity: understanding complex system dynamics by interfacing neurons with silicon technologies
Authors: Colicos Michael A. , Syed Naweed I.
Published: May 2006

Information processing in the central nervous system is primarily mediated through synaptic connections between neurons. This connectivity in turn defines how large ensembles of neurons may coordinate network output to execute complex sensory and motor functions including learning and memory. The synaptic connectivity between any given pair of neurons is not hard-wired;rather it exhibits a high degree of plasticity, which in turn forms the basis for learning and memory. While there has been extensive research to define the cellular and molecular basis of synaptic plasticity, at the level of either pairs of neurons or smaller networks, analysis of larger neuronal ensembles has proved technically challenging. The ability to monitor the activities of larger neuronal networks simultaneously and non-invasively is a necessary prerequisite to understanding how neuronal networks function at the systems level. Here we describe recent breakthroughs in the area of various bionic hybrids whereby neuronal networks have been successfully interfaced with silicon devices to monitor the output of synaptically connected neurons. These technologies hold tremendous potential for future research not only in the area of synaptic plasticity but also for the development of strategies that will enable implantation of electronic devices in live animals during various memory tasks.
Phenotypic plasticity, sexual selection and the evolution of colour patterns
Authors: Price Trevor D.
Published: May 2006

When a population comes to occupy a new environment, phenotypically plastic responses alter the distribution of phenotypes, and hence affect both the direction and the intensity of selection. Rates of evolution can be accelerated or retarded compared to what would happen in the absence of plasticity. Plastic responses in one trait result in novel selection pressures on other traits, and this can lead to evolution in completely different directions than predicted in the absence of plasticity. In this paper I use the concept of the adaptive surface in order to identify conditions under which the various different outcomes are expected. I then discuss differences between sexually and naturally selected traits. Sexually selected traits are often expected to be plastic in their expression, with individuals in high condition developing greater elaboration. As examples of sexually selected traits I review the evolution of colour patterns in birds with a view to assessing the magnitude of plastic responses in their development, and to ask how such responses may have influenced genetic evolution. The common colour pigments in birds are carotenoids and melanins. Both are used in social signaling, and consequently are expected to evolve to be phenotypically plastic indicators of an individual's quality. Perhaps partly because they are condition indicators, the quantity of carotenoids in the plumage can be strongly influenced by diet. Examples are described where alterations of carotenoids in the diet are thought to have altered the phenotype, driving genetic evolution in novel directions. Melanin patterns seem to be less affected by diet, but the intensity of melanization after moult is affected by social interactions during the moult and by raising birds in humid conditions. Hormonal manipulations can have dramatic effects on both the kinds of melanin produced (eumelanin or phaeomelanin) as well as the patterns they form. Differences between species in melanin patterns resemble differences produced by environmental manipulations, as well as those produced by simple modulations of parameters in computer simulations of pattern formation. While phenotypic plasticity is one way that genetic change in plumage patterns (and other traits) could be driven, there are others, including the appearance of major mutations and selection on standing variation whose distribution is not altered in the new environment. I consider some evidence for the different alternatives, and ask when they might lead to qualitatively different evolutionary outcomes.
Post-genomic approaches to understanding the mechanisms of environmentally induced phenotypic plasticity
Authors: Cossins Andrew , Fraser Jane , Hughes Margaret , Gracey Andrew
Published: May 2006

Post-genomic techniques offer new and detailed insights into the mechanisms underpinning all biological processes, including phenotypic plasticity and environmentally relevant phenotypes. Although they require access to genomic resources it is now possible to create these for species of comparative or environmental interest even within a modest research project. Here we describe an open transcript screen for genes responding to environmental cold that might account for the acquired cold-specific phenotype in all its complex manifestations. Construction of a cDNA microarray led to a survey of transcript expression levels in seven tissues of carp, as a function of time,and three different extents of cooling. The resulting data delineated a common stress response found in all tissues that comprises genes involved in cellular homeostasis, including energy charge, ATP turnover, protein turnover and stress protein production. These genes respond to kinds of perturbation other than cold and probably form part of a more general stress response common to other species. We also defined tissue-specific response patterns of transcript regulation whose main characteristics were investigated by a profiling technique based on categorisation of gene function. These genes underpin the highly tissue-specific pattern of physiological adaptations observed in the cold-acclimated fish. As a result we have identified a large number of candidate gene targets with which to investigate adaptive responses to environmental challenge.
The evolutionary consequences of ecological interactions mediated through phenotypic plasticity
Authors: Fordyce James A.
Published: May 2006

Phenotypic plasticity describes the capacity of a genotype to exhibit a range of phenotypes in response to variation in the environment. Environmental variation encompasses both abiotic and biotic components of the environment,including interactions among organisms. The strength and outcome of many ecological interactions, ranging from antagonism to mutualism, are mediated through the phenotypically plastic responses of one or more players in the interaction. Herein, three broadly defined, non-mutually exclusive,evolutionary consequences of ecological interactions mediated through phenotypic plasticity are discussed. (1) The predictable plastic response of one partner can favor behaviors, physiological responses, and life history traits of an interacting partner that manipulate, circumvent, or ameliorate the response of that partner. (2) Phenotypic plasticity can generate substantial spatial and temporal variation within and among populations. Such phenotypic variation can depend on the density and identity of interacting players in an ecological community, and can ultimately affect the evolutionary outcome of ecological interactions. (3) Phenotypic plasticity affects the strength and direction of natural selection. Ecological interactions mediated through phenotypic plasticity are ubiquitous in nature, and the potential evolutionary consequences of these interactions illustrate the complexity inherent in understanding evolution in a community context.
Study of single molecules and their assemblies by scanning tunneling microscopy
Authors: Hou J. G. , Wang Kedong
Published: May 2006

The recent rapid advances in nanotechnology, especially those based on molecules, are due in large part to our newly acquired abilities to measure and manipulate individual molecules and their assemblies. Among all the approaches for the study of single molecules, scanning tunneling microscopy (STM) is unique and powerful owing to its ability to accurately probe and control single molecules. High-resolution spatial imaging combined with scanning tunneling spectroscopy (STS) helps scientists investigate and resolve many chemical and physical problems at the molecular level. In this paper, we review our recent studies of single molecules and their assemblies by combining STM experiments and theoretical simulations based on the density functional theory (DFT).
Peptidomics: A modern approach to biodiversity of peptides
Authors: Ivanov Vadim T. , Yatskin Oleg N. , Sazonova Olga V. , Tolmazova Anna G. , Leontiev Konstantin V. , Philippova Marina M. , Karelin Andrei A. , Blishchenko Elena Yu.
Published: May 2006

Murine myelomonocytes WEHI-3 and human erythroid leukemia K562 cells were shown to release peptides into the surrounding medium. Four N-terminal sequences of the peptides derived from unknown protein precursors were identified in the conditioned medium of WEHI-3 culture. Twelve N-terminal sequences of the peptides released by K562 cells were established. K562 cells were shown to release long hemoglobin α- and ε-chains fragments, as well as peptides derived from carbonic anhydrase XI, melanophilin, cadherin EGF LAG G-type receptor 2, aldolase A, melastatin 1, peptide homologous to ryanodine receptor fragment, and a few peptides derived from the proteins with unknown function.

Comparative analysis of the peptides released by the intact erythroid leukemia K562 cells and the same cells after differentiation (induced by guanosine monophosphate, GMP, and accompanied by start of hemoglobin biosynthesis), has demonstrated that the level of six components, including all established hemoglobin fragments, carbonic anhydrase fragment, and the fragment of the unknown protein significantly increased in the course of differentiation. The spectrum of the peptides released by K562 cells strongly differed from that of the mature erythrocytes: (1) in contrast to the mature erythrocytes, K562 cells release long α-globin fragments and the fragment of ε-globin; (2) erythrocytes almost exclusively release the products of hemoglobin proteolysis; in the case of K562 cells the fragments of enzymes, receptors, and other functional proteins were found. So, the concentration and the content of the individual peptides released by the cells depend on the differentiation state.

The comparative analysis of the dynamics of peptide secretion by human erythrocytes performed in the presence and the absence of the 3 % glucose has shown that the rate of the peptide release strongly depends on cell metabolism. In summary, peptidomic studies of cell cultures provide valuable information on the mechanisms of peptide pool formation in tissues and the whole organism.
Enhanced P-stereodependent stability of complexes formed by phosphorothioate oligonucleotides due to involvement of sulfur as strong hydrogen bond acceptor
Authors: Guga Piotr , Boczkowska Małgorzata , Janicka Magdalena , Maciaszek Anna , Nawrot Barbara , Antoszczyk Sławomir , Stec Wojciech J.
Published: May 2006

The antisense or antigene properties are exerted not only by natural oligonucleotides, but also by their different analogs. Among them, phosphorothioate oligonucleotides (PS-DNA), in which the sugar-phosphate backbone is modified due to substitution of the sulfur atom for one of the nonbridging oxygens, are much more resistant toward nucleases and, simultaneously, maintain good hybridization properties. However, the substitution induces the P-chirality of dinucleoside phosphorothioate moiety and even short PS-DNA synthesized using standard chemical methods exist as a mixture of hundreds or thousands of diastereoisomers. Diastereomerically pure oligomers of [PS]-d(CG)4 and [PS]-d(GC)4 series, obtained using the oxathiaphospholane method, were investigated with respect to their ability to adopt the left-handed conformation at high sodium chloride concentration. Obtained data allow us to postulate the formation of a strong intramolecular hydrogen bond with anionic sulfur atom as an acceptor. Homopurine [All-RP-PS]-oligos, but not [All-SP-PS]-oligos, form with the RNA templates extremely stable triplex structures, so far not described in the literature. Most likely, the triplexes are stabilized by hydrogen bonds or water bridges with the participation of sulfur atoms of internucleotide linkage. Notably, target RNA molecules are "arrested" by properly designed [All-RP-PS]-DNA probes at submicromolar concentration, and as the result, they are not recognized by reverse transcriptase.
Structure and phase behavior of two-dimensional solids formed at interfaces
Authors: Inaba Akira
Published: May 2006

Molecular monolayers adsorbed to solid surfaces such as graphite are distinct from the bulk in their physicochemical properties because of the 2D nature. In most cases, they form a well-defined 2D crystalline solid. We have been investigating such systems of various simple molecules by means of the synergetic use of X-ray diffraction, neutron scattering, and calorimetry. Selected examples illustrate that the reduced dimensionality has important consequences for the structure, dynamics, and phase behavior in the condensed state. In some cases, the similar solid monolayers are formed at the liquid-graphite interfaces, where they also show a rich variety of the structure and phase behavior. For the multicomponent system of those monolayers, mixing behavior is particularly interesting from both the structural and thermodynamic points of view. We also investigated ice crystallization from the solution, where a 2D nature was found in structure in the initial stage of crystallization.
Applications of capillary electrophoresis to high-sensitivity analyses of biomolecules
Authors: Terabe Shigeru , Monton Maria Rowena N. , Le Saux Thomas , Imami Koshi
Published: May 2006

To increase the detection sensitivity of capillary electrophoresis (CE) and thereby widen its application to biomolecular analyses, we have developed a number of on-line preconcentration strategies, i.e., techniques to increase sample loading without compromising resolution and efficiency. Two such techniques, namely, dynamic pH junction and field-enhanced sample injection (FESI) are covered in this work. Dynamic pH junction is predicated on a sharp reduction in an analyte's migration velocity following a reversal of its electrophoretic direction from the acidic sample zone to the basic background solution (BGS) zone. FESI, on the other hand, depends on the retardation of analyte velocity as it transits from the low-conductivity sample zone to the high-conductivity milieu of the BGS zone. Their applications to high-sensitivity analyses of peptides and proteins are discussed.
Errata - Guidelines for terminology for microtechnology in clinical laboratories (IUPAC Technical Report)
Authors: Wilding P. , Joos T. , Kricka L. J. , Shi L.
Published: May 2006

In the original article.
Assessment of Tocopherol Metabolism and Oxidative Stress in Familial Hypobetalipoproteinemia
Authors: Clarke Michael W , Hooper Amanda J , Headlam Henrietta A , Wu Jason HY , Croft Kevin D , Burnett John R
Published: May 2006

Background: Vitamin E supplementation has been recommended for persons with familial hypobetalipoproteinemia (FHBL), a rare disorder of lipoprotein metabolism that leads to low serum α-tocopherol and decreased LDL-cholesterol and apolipoprotein (apo) B. We examined the effect of truncated apoB variants on vitamin E metabolism and oxidative stress in persons with FHBL.

Methods: We studied 9 individuals with heterozygous FHBL [mean (SE) age, 40 (5) years; body mass index (BMI), 27 (10) kg/m2] and 7 normolipidemic controls [age, 41 (5) years; BMI, 25 (2) kg/m2]. We also studied 3 children—2 with homozygous FHBL (apoB-30.9) and 1 with abetalipoproteinemia—who were receiving α-tocopherol supplementation. We used HPLC with electrochemical detection to measure α- and γ-tocopherol in serum, erythrocytes, and platelets, and gas chromatography–mass spectrometry to measure F2-isoprostanes and tocopherol metabolites in urine as markers of oxidative stress and tocopherol intake, respectively.

Results: Compared with controls, persons with FHBL had significantly lower fasting plasma concentrations of total cholesterol [2.4 (0.2) vs 4.7 (0.2) mmol/L], triglycerides [0.5 (0.1) vs 0.9 (0.1) mmol/L], LDL-cholesterol [0.7 (0.1) vs 2.8 (0.3) mmol/L], apoB [0.23 (0.02) vs 0.84 (0.08) g/L], α-tocopherol [13.6 (1.0) vs 28.7 (1.4) μmol/L], and γ-tocopherol [1.0 (0.1) vs 1.8 (0.3) μmol/L] (all P <0.03). Erythrocyte α-tocopherol was decreased [5.0 (0.2) vs 6.0 (0.3) μmol/L; P <0.005], but we observed no differences in lipid-adjusted serum tocopherols, erythrocyte γ-tocopherol, platelet α- or γ-tocopherol, urinary F2-isoprostanes, or tocopherol metabolites.

Conclusion: Taken together, our findings do not support the recommendation that persons with heterozygous FHBL receive vitamin E supplementation.
Realising the developmental potential of Clinical Governance
Authors: Degeling Peter
Published: May 2006

To be effective, Clinical Governance should reach all levels of a healthcare organisation. It requires structures and processes that integrate financial control, service performance, and clinical quality in ways that will engage clinicians and generate service improvements. The Clinical Governance arrangements of many Trusts, however, present several flaws. In particular, the “silos” organisational structure of Clinical Governance is based on generic issues such as risk management, clinical audit, clinical effectiveness and staff development, and it tends to treat clinical work as an undifferentiated aggregate. An alternative model focused on clinical pathways and on a balance between professional autonomy and accountability (responsible autonomy) should be promoted to make Clinical Governance work.
Involvement of patients in Clinical Governance
Authors: Freedman Danielle B.
Published: May 2006

Clinical Governance is a framework through which the National Health Service (NHS) organisations in the UK are accountable for continuously improving the quality of their services and safeguarding high standards by creating an environment in which excellence in clinical care will flourish. The NHS has moved on from being an organisation that simply delivered services to people, to being a service that is totally patient-led and responds to their needs and wishes. There are numerous national drivers and initiatives for patient involvement, including the
Clinical Governance and Laboratory Medicine: is the Electronic Medical Record our best friend or sworn enemy?
Authors: T. Shaw Nicola
Published: May 2006

This review attempts to address the question: is the Electronic Medical Record (EMR) our best friend or sworn enemy in the context of Clinical Governance and Laboratory Medicine? It provides a brief overview of the history and development of Clinical Governance before going on to define an EMR. It considers how EMRs could assist in delivering quality care in laboratory medicine. A number of outstanding issues regarding EMRs and electronic health records (EHRs) are identified and discussed briefly before the author provides a brief outlook on the future of clinical governance and EMRs in laboratory medicine.
Laboratory request appropriateness in emergency: impact on hospital organization
Authors: Trisorio Liuzzi Maria Pia , Attolini Ettore , Quaranta Roberto , Paparella Domenico , Cappabianca Giangiuseppe , Di Serio Francesca , Dell'Erba Alessandro S.
Published: May 2006

Within the activities of the Risk Management Unit of the Bari Polyclinic Hospital Corporation, an anomalous trend was found, with excessive requests for urgent laboratory tests being made in the time period between 05:00 and 07:45h. In addition to slowing down laboratory operations, this anomaly suggested the possibility of inappropriate testing, at least in terms of the request mode, if not in absolute terms. An audit was implemented within the facility to check the grounds of this suspicion and to identify any errors and/or critical points. The results gathered are extremely interesting, as they show deficiencies at both the organizational and clinical level. The final objective of the investigation is to draft a common corporate procedure.
Re-energising Clinical Governance through Integrated Governance
Authors: Deighan Michael , Bullivant John
Published: May 2006

The purpose of this paper is to accurately identify the future governance arrangements the NHS will follow, a close examination of the roles of Directors in implementing such a policy, and the National Policy documents that are required to put this in place.
Information Technology in Systems Biology (Informationstechnologien in der Systembiologie)
Authors: Schmidt Henning , Jirstrand Mats , Wolkenhauer Olaf
Published: May 2006

Information technology is an important part within the highly interdisciplinary scientific field of systems biology. In this paper we are presenting an overview over systems biology, focusing on the information technological aspects, current developments, and future challenges.
Computational Systems Biology Platforms (Computergestützte Systembiologieplattformen)
Authors: Vacheva Ivayla , Eils Roland
Published: May 2006

Numerous software platforms in Computational Systems Biology have been developed in the past decade. Each program has its own strengths but their functionality often overlaps significantly. In this article, we review numerous aspects related to the functionality and infrastructure of existing platforms in the context of a selected set of tools. We discuss the biological problems that can be solved with these tools and point out directions for future research in the field.
Tissue expression of the nuclear progesterone receptor in male non-human primates and men
Authors: Luetjens C Marc , Didolkar Aditya , Kliesch Sabine , Paulus Werner , Jeibmann Astrid , Böcker Werner , Nieschlag Eberhard , Simoni Manuela
Published: May 2006

In females, progesterone is associated with reproductive functions. In males, its role and the expression of its genomic receptor are not very well understood. In attempts to achieve a hormonal male contraceptive method, gestagens are used to downregulate gonadotropin and sperm production. It is therefore essential to understand the mechanism of action of progesterone at the molecular level in males, especially in primates. This investigation was undertaken: (a) to determine whether the genomic progesterone receptor is expressed in males; and (b) to locate it in various organs that are potential targets of gestagens. Human tissues were obtained at surgery for benign prostatic hyperplasia or prostate cancer and at autopsy. Non-human primate tissues were obtained at autopsy. This study was performed by analyzing the genomic progesterone receptor by immunohistochemistry, Western blot and RT-PCR. The nuclear progesterone receptor was expressed in pituitary and hypothalamus of both monkeys and men. In the testis progesterone receptor expression was found in a few peritubular and interstitial cells, but not in germ cells. In addition, expression was detected in the epididymis, prostate and male mammary gland. Reverse transcriptase (RT)-PCR experiments indicated that progesterone receptor A and B are expressed in all tissues analyzed. These data exclude direct genomic effects of gestagens at the spermatogenic level but indicate that a male contraceptive based on gestagens might have some effects on other tissues, such as the epididymis, prostate and mammary gland.
Early and rapid development of insulin resistance, islet dysfunction and glucose intolerance after high-fat feeding in mice overexpressing phosphodiesterase 3B
Authors: Walz Helena A , Härndahl Linda , Wierup Nils , Zmuda-Trzebiatowska Emilia , Svennelid Fredrik , Manganiello Vincent C , Ploug Thorkil , Sundler Frank , Degerman Eva , Ahrén Bo , Holst Lena Stenson
Published: May 2006

Inadequate islet adaptation to insulin resistance leads to glucose intolerance and type 2 diabetes. Here we investigate whether β-cell cAMP is crucial for islet adaptation and prevention of glucose intolerance in mice. Mice with a β-cell-specific, 2-fold overexpression of the cAMP-degrading enzyme phosphodiesterase 3B (RIP-PDE3B/2 mice) were metabolically challenged with a high-fat diet. We found that RIP-PDE3B/2 mice early and rapidly develop glucose intolerance and insulin resistance, as compared with wild-type littermates, after 2 months of high-fat feeding. This was evident from advanced fasting hyperinsulinemia and early development of hyper-glycemia, in spite of hyperinsulinemia, as well as impaired capacity of insulin to suppress plasma glucose in an insulin tolerance test. In vitro analyses of insulin-stimulated lipogenesis in adipocytes and glucose uptake in skeletal muscle did not reveal reduced insulin sensitivity in these tissues. Significant steatosis was noted in livers from high-fat-fed wild-type and RIP-PDE3B/2 mice and liver triacyl-glycerol content was 3-fold higher than in wild-type mice fed a control diet. Histochemical analysis revealed severe islet perturbations, such as centrally located α-cells and reduced immunostaining for insulin and GLUT2 in islets from RIP-PDE3B/2 mice. Additionally, in vitro experiments revealed that the insulin secretory response to glucagon-like peptide-1 stimulation was markedly reduced in islets from high-fat-fed RIP-PDE3B/2 mice. We conclude that accurate regulation of β-cell cAMP is necessary for adequate islet adaptation to a perturbed metabolic environment and protective for the development of glucose intolerance and insulin resistance.
The susceptibility of granulosa cells to apoptosis is influenced by oestradiol and the cell cycle
Authors: Quirk Susan M , Cowan Robert G , Harman Rebecca M
Published: May 2006

Experiments were conducted to test whether oestradiol (E2) protects granulosa cells from Fas ligand (FasL)-induced apoptosis and whether protection involves modulation of the cell cycle of proliferation. Treatment of cultured bovine granulosa cells with E2 decreased susceptibility to FasL-induced apoptosis. The effects of E2 were mediated through oestrogen receptor and were not mediated by stimulation of IGF production. E2 also increased the percentage of cells progressing from G1 to S phase of the cell cycle, and increased expression of cyclin D2 protein and the cell proliferation marker Ki67. Progression from G1 to S phase of the cell cycle was necessary for the protective effect of E2; blocking progression from G1 to S phase with the cdk2 inhibitor roscovitine, or blocking cells in S phase with hydroxyurea, prevented protection by E2. The stages of the cell cycle during which granulosa cells are susceptible to apoptosis were assessed. First, treatment with the G1 phase blocker, mimosine, protected cells from FasL-induced apoptosis, indicating that cells in G0 or early- to mid-G1 phase are relatively resistant to apoptosis. Secondly, examination of recent DNA synthesis by cells that became apoptotic indicated that apoptosis did not occur in S, G2 or M phases. Taken together, the experiments indicate that cells may be most susceptible to apoptosis at the transition from G1 to S phase. E2 stimulates transition from G1 to S phase and protects against apoptosis only when cell cycle progression is unperturbed.
Endocrine, liver-derived IGF-I is of importance for spatial learning and memory in old mice
Authors: Svensson J , Diez M , Engel J , Wass C , Tivesten Å , Jansson J-O , Isaksson O , Archer T , Hökfelt T , Ohlsson C
Published: May 2006

IGF-I is a neuroprotective hormone, and neurodegenerative disorders, including Alzheimer’s disease, have been associated with decreased serum IGF-I concentration. In this study, IGF-I production was inactivated in the liver of adult mice (LI-IGF-I−/−), resulting in an approximately 80–85% reduction of circulating IGF-I concentrations. In young (6-month-old) mice there was no difference between the LI-IGF-I−/− and the control mice in spatial learning and memory as measured using the Morris water maze test. In old (aged 15 and 18 months) LI-IGF-I−/− mice, however, the acquisition of the spatial task was slower than in the controls. Furthermore, impaired spatial working as well as reference memory was observed in the old LI-IGF−/− mice. Histochemical analyses revealed an increase in dynorphin and enkephalin immunoreactivities but decreased mRNA levels in the hippocampus of old LI-IGF-I−/− mice. These mice also displayed astrocytosis and increased metabotropic glutamate receptor 7a-immunoreactivity. These neurochemical disturbances suggest synaptic dysfunction and early neurodegeneration in old LI-IGF-I−/− mice. The decline in serum IGF-I with increasing age may therefore be important for the age-related decline in memory function.
Dose-dependent response of plasma ghrelin and growth hormone concentrations to bovine ghrelin in Holstein heifers
Authors: ThidarMyint Hnin , Yoshida Hiroko , Ito Tetsuya , Kuwayama Hideto
Published: May 2006

The stimulatory effect of the novel gastric-derived hormone, ghrelin, on growth hormone (GH) secretion has been reported in domestic animals as well as in humans and rats. The octanoyl modification on the Ser3 residue of ghrelin appears to be essential for its endocrine activity. A major portion of circulatory ghrelin lacks acylation but possesses some biological activities other than GH stimulation; therefore, both types of acylated and des-acyl ghrelin are supposed to be important for energy homeostasis. The effects of pharmacological doses of rat and/or human ghrelin on GH secretion have been reported recently in ruminants; however, the physiological effect of exogenous bovine ghrelin on its own plasma level and on GH secretion is still unknown. Moreover, the RIA systems for the measurement of bovine active ghrelin and for bovine total ghrelin including acylated ghrelin, des-acyl ghrelin and all ghrelin peptides with an intact bovine C-terminal have not yet been validated. In this study, we established the RIA system for bovine ghrelin, and the dose-dependent effects of synthesized acylated bovine ghrelin(1–27) on plasma active and total ghrelin, GH, insulin and metabolites were measured in Holstein heifers. Six animals were intravenously injected with synthesized acylated bovine ghrelin (0, 0.1, 0.5, 1.0, 5.0, 10.0 μg/kg body weight (BW)) and plasma hormone concentrations were measured from serially collected samples. Bovine ghrelin RIA showed that the basal level of total ghrelin is approximately 16 times higher than that of active ghrelin in bovine plasma. Both forms of ghrelin were increased in a dose-dependent manner in response to bovine ghrelin injections, peak values were reached at 5 min after administration and returned to pre-injected values within 15 min. Plasma GH was responsive to all doses of bovine ghrelin in a dose-dependent manner, peaked as early as at 5–10 min after injection and returned to the basal value within 60 min. The GH area under curve 1 h after injection of the smallest dose of ghrelin used in this experiment (0.1 μg/kg BW) was significantly higher than that of the vehicle (0.1% BSA saline)-injected control group (P<0.05). The GH response to the highest dose of ghrelin (10.0 μg/kg BW) was greater than the response to 5.0 μg/kg BW ghrelin (P<0.001). Plasma glucose concentrations were not significantly altered by the administration of bovine ghrelin while plasma insulin levels were transiently stimulated by the higher doses of ghrelin (1.0, 5.0, 10.0 μg/kg BW). Plasma non-esterified fatty acid levels also increased following ghrelin administration. Our study indicates that a considerable quantity of both acylated and des-acyl ghrelin is circulating in the bloodstream, and also confirms that ghrelin is not only a potent stimulator of GH secretion but also plays a considerable role in energy homeostasis in Holstein heifers.
Steroid hormone regulation of Clca3 expression in the murine uterus
Authors: Jeong J-W , Lee K Y , Lydon J P , DeMayo F J
Published: May 2006

Progesterone (P4) and its cognate receptor, the progesterone receptor (PGR), have important roles in the establishment and maintenance of pregnancy in the murine uterus. In previous studies, using high-density DNA microarray analysis, we identified a subset of genes whose expression is repressed by chronic P4-PGR activation in the uterus. The Clca3 gene is one of the genes whose expression is the most significantly downregulated by P4 and PGR. In the present study, we performed real-time RT–PCR and in situ hybridization to investigate the regulation of Clca3 by P4 and determine the pattern of expression of Clca3 in the uterus during early pregnancy. This analysis shows that Clca3 mRNA transcripts were detected in the luminal and glandular epithelium of the pseudopregnant uterus at day 0.5 and that the expression of Clca3 was not detected after day 3.5. P4 represses Clca3 mRNA synthesis in the luminal epithelial and glandular epithelial cells of the uterus in ovariectomized wild-type mice, but not in Pgr knockout (PRKO) mice. Conversely, estrogen (E2) induces Clca3 expression in the luminal epithelium and glandular epithelium, and this induction was repressed by P4 in the murine uterus. Analysis of the promoter region of Clca3 by in silico and transient transfection analysis in HEC-1A cells identified the regulation of Clca3 by estrogen receptor-alpha (ESR1) within the first 528 bp of 5′-flanking region of the Clca3 gene. Our studies identified Clca3 as a novel downregulated gene of PGR that is a direct target of E2 regulation.
Isolation of the cDNA encoding the acid labile subunit (ALS) of the 150 kDa IGF-binding protein complex in cattle and ALS regulation during the transition from pregnancy to lactation
Authors: Kim Jin W , Rhoads Robert P , Segoale Nthabisheng , Kristensen Niels B , Bauman Dale E , Boisclair Yves R
Published: May 2006

During the transition from pregnancy to lactation, dairy cows experience a 70% reduction in plasma IGF-I. This reduction has been attributed to decreased hepatic IGF-I production. IGF-I circulates predominantly in multi-protein complexes consisting of one molecule each of IGF-I, IGF binding protein-3 and the acid labile subunit (ALS). Recent studies in the mouse have shown that absence of ALS results in accelerated turnover and severely depressed concentration of plasma IGF-I. These observations suggest that reduced plasma ALS could be a second factor contributing to the fall of plasma IGF-I in peri-parturient cows. This possibility has not been studied due to the lack of bovine ALS reagents. To address this, we isolated the bovine ALS cDNA and used its sequence to develop a ribonuclease protection assay (RPA) and a bovine ALS antiserum. Using the RPA, ALS mRNA abundance was approximately fivefold higher in liver than in lung, small intestine, adipose tissue, kidney and heart, but was absent in muscle and brain. The antiserum detected the highest ALS levels in plasma followed by ovarian follicular fluid, lymph and colostrum. A portion of colostrum and follicular fluid ALS appears to be synthesized locally as ALS mRNA was found in mammary epithelial cells and ovarian follicular cells. Finally, we measured plasma ALS in dairy cows during the peri-parturient period (days −35 and +56 relative to parturition on day 0). Plasma ALS dropped by 50% between late pregnancy and the first day of lactation and returned to prepartum levels by day +56. To determine whether this reflected a change in hepatic expression, ALS mRNA was measured in liver biopsies collected on days −35, +3 and +56. ALS mRNA expression was significantly lower on day +3 than on day −35, but recovered completely by day +56. Finally, we examined the ability of GH to increase plasma ALS abundance at selected times before and after parturition (weeks −5, −2, +1 and +5). GH increased plasma ALS at weeks −5, −2 and +5, but not at week +1. Identical effects of GH were seen when the response considered was plasma IGF-I. We conclude that the decline in plasma ALS after parturition is a consequence of hepatic GH resistance and contributes to the associated reduction of plasma IGF-I.
Adiponectin Suppression of High-Glucose–Induced Reactive Oxygen Species in Vascular Endothelial Cells
Authors: Ouedraogo Raogo , Wu Xiangdong , Xu Shi-Qiong , Fuchsel Lauren , Motoshima Hiroyuki , Mahadev Kalyankar , Hough Kelly , Scalia Rosario , Goldstein Barry J.
Published: May 2006

Adiponectin is an abundant adipocyte-derived plasma protein with antiatherosclerotic effects. Vascular signal transduction by adiponectin is poorly understood and may involve 5′-AMP–activated protein kinase (AMPK), cAMP signaling, and other pathways. Hyperglycemia sharply increases the production of reactive oxygen species (ROS), which play a key role in endothelial dysfunction in diabetes. Because the recombinant globular domain of human adiponectin (gAd) reduces the generation of endothelial ROS induced by oxidized LDL, we sought to determine whether adiponectin could also suppress ROS production induced by high glucose in cultured human umbilical vein endothelial cells. Incubation in 25 mmol/l glucose for 16 h increased ROS production 3.8-fold (P < 0.05), using a luminol assay. Treatment with gAd for 16 h suppressed glucose-induced ROS in a dose-dependent manner up to 81% at 300 nmol/l (P < 0.05). The AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR; 1 mmol/l, 16 h) only partially decreased glucose-induced ROS by 22% (P < 0.05). Cell pretreatment with AMPK inhibitors, however, failed to block the effect of gAd to suppress glucose-induced ROS, suggesting that the action of gAd was independent of AMPK. Interestingly, activation of cAMP signaling by treatment with forskolin (2 μmol/l) or dibutyryl-cAMP (0.5 mmol/l) reduced glucose-induced ROS generation by 43 and 67%, respectively (both P < 0.05). Incubation with the cAMP-dependent protein kinase (PKA) inhibitor H-89 (1 μmol/l) fully abrogated the effect of gAd, but not that of AICAR, on ROS induced by glucose. gAd also increased cellular cAMP content by 70% in an AMPK-independent manner. Full-length adiponectin purified from a eukaryotic expression system also suppressed ROS induced by high glucose or by treatment of endothelial cells with oxidized LDL. Thus, adiponectin suppresses excess ROS production under high-glucose conditions via a cAMP/PKA-dependent pathway, an effect that has implications for vascular protection in diabetes.
Decreased Muscle Strength and Quality in Older Adults With Type 2 Diabetes
Authors: Park Seok Won , Goodpaster Bret H. , Strotmeyer Elsa S. , de Rekeneire Nathalie , Harris Tamara B. , Schwartz Ann V. , Tylavsky Frances A. , Newman Anne B.
Published: May 2006

Adequate skeletal muscle strength is essential for physical functioning and low muscle strength is a predictor of physical limitations. Older adults with diabetes have a two- to threefold increased risk of physical disability. However, muscle strength has never been investigated with regard to diabetes in a population-based study. We evaluated grip and knee extensor strength and muscle mass in 485 older adults with diabetes and 2,133 without diabetes in the Health, Aging, and Body Composition study. Older adults with diabetes had greater arm and leg muscle mass than those without diabetes because they were bigger in body size. Despite this, muscle strength was lower in men with diabetes and not higher in women with diabetes than corresponding counterparts. Muscle quality, defined as muscle strength per unit regional muscle mass, was significantly lower in men and women with diabetes than those without diabetes in both upper and lower extremities. Furthermore, longer duration of diabetes (≥6 years) and poor glycemic control (HbA1c >8.0%) were associated with even poorer muscle quality. In conclusion, diabetes is associated with lower skeletal muscle strength and quality. These characteristics may contribute to the development of physical disability in older adults with diabetes.