JoVE   
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Biology

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Neuroscience

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Immunology and Infection

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Clinical and Translational Medicine

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Bioengineering

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Applied Physics

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Chemistry

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Behavior

  
You do not have subscription access to articles in this section. Learn more about access.

  JoVE Environment

|   

JoVE Science Education

General Laboratory Techniques

You do not have subscription access to videos in this collection. Learn more about access.

Basic Methods in Cellular and Molecular Biology

You do not have subscription access to videos in this collection. Learn more about access.

Model Organisms I

You do not have subscription access to videos in this collection. Learn more about access.

Model Organisms II

You do not have subscription access to videos in this collection. Learn more about access.

In JoVE (1)

Other Publications (74)

Articles by Maria Eriksson in JoVE

 JoVE Clinical and Translational Medicine

Near Infrared Optical Projection Tomography for Assessments of β-cell Mass Distribution in Diabetes Research

1Umeå Centre for Molecular Medicine, Umeå University, 2Cell Transplant Center, Diabetes Research Institute, University of Miami,, 3EMBL-CRG Systems Biology Program, Centre for Genomic Regulation, Catalan Institute of Research and Advanced Studies, 4Dept. of Computing Science, Umeå University


JoVE 50238

We describe the adaptation of optical projection tomography (OPT)1 to imaging in the near infrared spectrum, and the implementation of a number of computational tools. These protocols enable assessments of pancreatic β-cell mass (BCM) in larger specimens, increase the multichannel capacity of the technique and increase the quality of OPT data.

Other articles by Maria Eriksson on PubMed

Long-term Outcome in Patients with Apical Hypertrophic Cardiomyopathy

The aim of this study was to describe long-term outcome in patients with apical hypertrophic cardiomyopathy (ApHCM) followed in a tertiary referral center.

Cloning and Expression of the Human N-methyl-D-aspartate Receptor Subunit NR3A

Native N-methyl-D-aspartate (NMDA) receptors are heteromeric assemblies of four or five subunits. The NMDA receptor subunits, NR1, NR2A, NR2B, NR2C, and NR2D have been cloned in several species, including man. The NR3A subunit, which in rodents is predominantly expressed during early development, seems to function by reducing the NMDA receptor response. The human homologue to the rat NR3A, however, had not been cloned. In order to study the functions of the human NR3A (hNR3A), we have cloned and sequenced the hNR3A. It was found to share 88% of the DNA sequence with the rat gene, corresponding to a 93% homology at the amino acid level. Based on available data from human genome databases, we localized the gene to chromosome 9. The transcript could be detected by in situ hybridization in human fetal spinal cord and forebrain. Two splice variants of NR3A have been reported in rat brain, the longer of the two containing a 60 bp insert in the intracellular domain. We were unable to detect this 60 bp insert in fetal or adult human brain, suggesting that only the short variant is expressed in humans.

Daylength and Spatial Expression of a Gibberellin 20-oxidase Isolated from Hybrid Aspen (Populus Tremula L. X P. Tremuloides Michx.)

Physiologically active gibberellins (GAs) are key regulators of shoot growth in trees. To investigate this mechanism of GA-controlled growth in hybrid aspen, we cloned cDNAs encoding gibberellin 20-oxidase (GA 20-oxidase), a key, highly regulated enzyme in the biosynthesis of GAs. Clones were isolated from leaf and cambium cDNA libraries using probes generated by polymerase chain reaction, based on conserved domains of GA 20-oxidases. Upon expression in Escherichia coli, the GST-fusion protein was shown to oxidise GA12 as well as oxidising the 13-hydroxylated substrate GA53, successively to GA9 and GA20, respectively. The gene PttGA20ox1 was expressed in meristematic cells and growing tissues such as expanding internodes, leaves and roots. The expression was negatively regulated by both GA4 and overexpression of phytochrome A. RNA analysis also showed that the expression was down-regulated in late-expanding leaf tissue in response to short days (SDs). Actively growing tissues such as early elongating internodes, petioles and leaf blades had the highest levels of C19-GAs. Upon transfer to SDs an accumulation of GA19 was observed in early elongating internodes and leaf blades. The levels of C19-GAs were also to some extent changed upon transfer to SDs. The levels of GA20 were down-regulated in internodes, and those of GA1 were significantly reduced in early expanding leaf blades. In roots the metabolites GA19 and GA8 decreased upon shifts to SDs, while GA20 accumulated slightly. The down-regulation of GA 20-oxidase activity in response to SDs was further indicated by studies of [14C]GA12 metabolism in shoots, demonstrating that the substrate for GA 20-oxidase, [14C]GA53, accumulates in SDs.

Antitumor Activity of the Angiogenesis Inhibitor TNP-470 on Murine Lymphoma/leukemia Cells in Vivo and in Vitro

The aim of this study was to evaluate the effects of an angiogenesis inhibitor in a non-immunocompromised setting in which transplanted tumor cells home and expand in a manner mimicking the original tumor in the donor. We used a novel animal model for T-cell lymphoma/leukemia (TLL) to test the antitumor effect of TNP-470, a well-established angiogenesis inhibitor.

Results of Surgery for Aortic Root Aneurysm in Patients with Marfan Syndrome

This study was undertaken to examine the long-term results of surgery for aortic root aneurysm in patients with Marfan syndrome.

Relation of Hypertriglyceridemia to Plasma Concentrations of Biochemical Markers of Inflammation and Endothelial Activation (C-reactive Protein, Interleukin-6, Soluble Adhesion Molecules, Von Willebrand Factor, and Endothelin-1)

Recurrent De Novo Point Mutations in Lamin A Cause Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by features reminiscent of marked premature ageing. Here, we present evidence of mutations in lamin A (LMNA) as the cause of this disorder. The HGPS gene was initially localized to chromosome 1q by observing two cases of uniparental isodisomy of 1q-the inheritance of both copies of this material from one parent-and one case with a 6-megabase paternal interstitial deletion. Sequencing of LMNA, located in this interval and previously implicated in several other heritable disorders, revealed that 18 out of 20 classical cases of HGPS harboured an identical de novo (that is, newly arisen and not inherited) single-base substitution, G608G(GGC > GGT), within exon 11. One additional case was identified with a different substitution within the same codon. Both of these mutations result in activation of a cryptic splice site within exon 11, resulting in production of a protein product that deletes 50 amino acids near the carboxy terminus. Immunofluorescence of HGPS fibroblasts with antibodies directed against lamin A revealed that many cells show visible abnormalities of the nuclear membrane. The discovery of the molecular basis of this disease may shed light on the general phenomenon of human ageing.

The Circadian Clock. A Plant's Best Friend in a Spinning World

Septal Ethanol Ablation for Hypertrophic Obstructive Cardiomyopathy: Early and Intermediate Results of a Canadian Referral Centre

Septal ethanol ablation (SEA) is a relatively new interventional nonsurgical treatment for patients with hypertrophic obstructive cardiomyopathy (HOCM). This procedure involves targeted infarction of the basal interventricular septum to reduce left ventricular outflow tract (LVOT) obstruction.

Early Results of a New Mechanical Tri-leaflet Heart Valve Prosthesis--"Tricusp": an Animal Study

A new tri-leaflet mechanical heart valve made of titanium was inserted in the mitral position to evaluate early results.

Response Regulator Homologues Have Complementary, Light-dependent Functions in the Arabidopsis Circadian Clock

TIMING OF CAB EXPRESSION 1 ( TOC1) functions with CIRCADIAN CLOCK-ASSOCIATED 1 (CCA1) in a transcriptional feedback loop that is important for the circadian clock in Arabidopsis thaliana (L.) Heynh. TOC1 and its four paralogues, the Arabidopsis PSEUDO-RESPONSE REGULATOR (PRR) genes, are expressed in an intriguing daily sequence. This was proposed to form a second feedback loop, similar to the interlocking clock gene circuits in other taxa. We show that prr9 and prr5 null mutants have reciprocal period defects for multiple circadian rhythms, consistent with subtly altered expression patterns of CCA1 and TOC1. The period defects are conditional on light quality and combine additively in double-mutant plants. Thus PRR9 and PRR5 modulate light input to the circadian clock but are neither uniquely required for rhythm generation nor form a linear series of mutual PRR gene regulation.

Changes in Gene Expression in the Wood-forming Tissue of Transgenic Hybrid Aspen with Increased Secondary Growth

Transgenic lines of hybrid aspen with elevated levels of gibberellin (GA) show greatly increased numbers of xylem fibres and increases in xylem fibre length. These plants therefore provide excellent models for studying secondary growth. We have used cDNA microarry analysis to investigate how gene transcription in the developing xylem is affected by GA-induced growth. A recent investigation has shown that genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under developmental-stage-specific transcriptional control. The present study shows that the highest transcript changes in our transgenic trees occurs in genes generally restricted to the early stages of xylogenesis, including cell division, early expansion and late expansion. The results reveal genes among those arrayed that are up-regulated with an increased xylem production, thus indicating key components in the production of wood.

Accumulation of Mutant Lamin A Causes Progressive Changes in Nuclear Architecture in Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disorder, commonly caused by a point mutation in the lamin A gene that results in a protein lacking 50 aa near the C terminus, denoted LADelta50. Here we show by light and electron microscopy that HGPS is associated with significant changes in nuclear shape, including lobulation of the nuclear envelope, thickening of the nuclear lamina, loss of peripheral heterochromatin, and clustering of nuclear pores. These structural defects worsen as HGPS cells age in culture, and their severity correlates with an apparent increase in LADelta50. Introduction of LADelta50 into normal cells by transfection or protein injection induces the same changes. We hypothesize that these alterations in nuclear structure are due to a concentration-dependent dominant-negative effect of LADelta50, leading to the disruption of lamin-related functions ranging from the maintenance of nuclear shape to regulation of gene expression and DNA replication.

Real-time RT-PCR for CTG Repeat-containing Genes

Myotonic dystrophy (DM1) is a neuromuscular disorder caused by a CTGn expansion in the 3'-untranslated region (UTR) of myotonic dystrophy protein kinase (DMPK). SIX5 is a homeodomain gene located just downstream of the repeat, and myotonic dystrophy WD protein (DMWD) is located close upstream of DMPK. It has been hypothesized that the expansion might influence the expression of the three myotonic dystrophy locus genes (DM1-locus), contributing to the complex and varied phenotype in this disorder. Real-time quantitative reverse transcription-polymerase chain reaction, or TaqMan, is a very sensitive method that enables quantification of expression levels of genes from small amounts of tissue and lowly expressed genes. Because data are collected during the assay, the quantification is possible over a wide range of expression levels. By the use of a standard curve and an endogenous control, we have applied the TaqMan system for absolute quantification of the expression levels of the three genes (DMPK, DMWD, and SIX5) in the same tissue sample.

[Are Combat Sports and Medical Ethics Compatible?]

Amenorrhea in Female Athletes is Associated with Endothelial Dysfunction and Unfavorable Lipid Profile

The aim of this study was to evaluate endothelial function measured as flow-mediated dilatation (FMD) of the brachial artery and blood markers of cardiovascular disease in young female endurance athletes with menstrual disturbance. Age- and body mass index-matched groups of young endurance athletes with amenorrhea (n = 14), oligomenorrhea (n = 9), and regular cycles (n = 12) and sedentary controls (n = 12) were compared with respect to endothelial function, lipid profile, markers of inflammation, and endocrine status. We found a significantly decreased FMD in the amenorrheic athletes, compared with all other groups. Amenorrheic athletes also had the most unfavorable lipid profile with significantly higher total cholesterol and low-density lipoprotein, compared with the other athlete groups. The oligomenorrheic athletes had the lowest levels of total cholesterol, low-density lipoprotein, and apolipoprotein B of all groups and significantly lower in comparison with the amenorrheic group. However, with respect to FMD, the oligomenorrheic group represented an intermediate between amenorrheic and regularly cycling subjects. There was a gradual impairment of FMD and the lipid profile to the degree of menstrual disturbance supporting an association with estrogen status. We conclude that amenorrhea in young endurance athletes is associated with endothelial dysfunction and unfavorable lipid profile. Additional studies are needed to elucidate the clinical implications of these results with regard to long-term risk for cardiovascular disease.

Oral Contraceptives Improve Endothelial Function in Amenorrheic Athletes

Athletic amenorrhea has been associated with endothelial dysfunction and unfavorable lipid profile. Estrogen substitution may reverse these metabolic consequences. The aim of this study was to evaluate the effects of oral contraceptives (OCs) on endothelial function measured as flow-mediated dilatation (FMD) of the brachial artery, the lipid profile, and blood markers of endothelial activation (inflammation) in amenorrheic athletes. Age- and body mass index-matched groups of young endurance athletes with amenorrhea (n = 11), regularly cycling athletes (n = 13), and sedentary controls (n = 12) were examined before and after 9 months of treatment with a low dose, monophasic, combined OC (30 mug ethinyl estradiol and 150 mug levonorgestrel). The amenorrheic athletes displayed the lowest FMD at baseline and the largest increase after OC treatment. FMD also increased in the control group, but not in the regularly menstruating athletes, who had the highest values of FMD before treatment. All three groups, particularly the controls, showed moderate unfavorable changes in the lipid profile in accordance with previous known effects of a second generation OC. Furthermore, there was an overall increase in some inflammatory markers (high sensitive C-reactive protein and TNF-alpha) and a decrease in one of the markers (vascular cell adhesion molecule-1). We conclude that amenorrheic athletes benefit from treatment with OC with respect to endothelial function. OC treatment is also associated with some modest alterations in the lipid profile and in markers of inflammation.

Athlete's Heart in Postmenopausal Former Elite Endurance Female Athletes

To investigate cardiac structure and function and exercise capacity in senior former elite athlete women.

Mitral Annular Disjunction in Advanced Myxomatous Mitral Valve Disease: Echocardiographic Detection and Surgical Correction

Mitral annular disjunction is a structural abnormality of the mitral annulus fibrosus described by pathologists in association with mitral leaflet prolapse and defined as a separation between the atrial wall-mitral valve (MV) junction and the left ventricular attachment allowing for hypermobility of the MV apparatus. The transesophageal echocardiographic characteristics of this abnormality have not been previously described. In patients undergoing MV repair for myxomatous MV degeneration and evaluated using a standardized transesophageal echocardiographic protocol, annular disjunction (mean value 10 +/- 3 mm) was seen at the base of the posterior leaflet in 98% of patients with advanced, and in 9% of patients with mild/moderate MV degeneration. There was a significant correlation between the magnitude of disjunction and the number of segments with prolapse/flail (r = 0.397, P = .001). We found annular disjunction to be a common component of MV apparatus in advanced MV degeneration. Its recognition on transesophageal echocardiography is important to facilitate optimal MV repair. The modification of the repair technique allows surgical correction of the annular disjunction, which seems to optimize long-term results in these challenging cases.

Forward Genetic Analysis of the Circadian Clock Separates the Multiple Functions of ZEITLUPE

The circadian system of Arabidopsis (Arabidopsis thaliana) includes feedback loops of gene regulation that generate 24-h oscillations. Components of these loops remain to be identified; none of the known components is completely understood, including ZEITLUPE (ZTL), a gene implicated in regulated protein degradation. ztl mutations affect both circadian and developmental responses to red light, possibly through ZTL interaction with PHYTOCHROME B (PHYB). We conducted a large-scale genetic screen that identified additional clock-affecting loci. Other mutants recovered include 11 new ztl alleles encompassing mutations in each of the ZTL protein domains. Each mutation lengthened the circadian period, even in dark-grown seedlings entrained to temperature cycles. A mutation of the LIGHT, OXYGEN, VOLTAGE (LOV)/Period-ARNT-Sim (PAS) domain was unique in retaining wild-type responses to red light both for the circadian period and for control of hypocotyl elongation. This uncoupling of ztl phenotypes indicates that interactions of ZTL protein with multiple factors must be disrupted to generate the full ztl mutant phenotype. Protein interaction assays showed that the ztl mutant phenotypes were not fully explained by impaired interactions with previously described partner proteins Arabidopsis S-phase kinase-related protein 1, TIMING OF CAB EXPRESSION 1, and PHYB. Interaction with PHYB was unaffected by mutation of any ZTL domain. Mutation of the kelch repeat domain affected protein binding at both the LOV/PAS and the F-box domains, indicating that interaction among ZTL domains leads to the strong phenotypes of kelch mutations. Forward genetics continues to provide insight regarding both known and newly discovered components of the circadian system, although current approaches have saturated mutations at some loci.

Progressive Vascular Smooth Muscle Cell Defects in a Mouse Model of Hutchinson-Gilford Progeria Syndrome

Children with Hutchinson-Gilford progeria syndrome (HGPS) suffer from dramatic acceleration of some symptoms associated with normal aging, most notably cardiovascular disease that eventually leads to death from myocardial infarction and/or stroke usually in their second decade of life. For the vast majority of cases, a de novo point mutation in the lamin A (LMNA) gene is the cause of HGPS. This missense mutation creates a cryptic splice donor site that produces a mutant lamin A protein, termed "progerin," which carries a 50-aa deletion near its C terminus. We have created a mouse model for progeria by generating transgenics carrying a human bacterial artificial chromosome that harbors the common HGPS mutation. These mice develop progressive loss of vascular smooth muscle cells in the medial layer of large arteries, in a pattern very similar to that seen in children with HGPS. This mouse model should prove valuable for testing experimental therapies for this devastating disorder and for exploring cardiovascular disease in general.

Mutant Nuclear Lamin A Leads to Progressive Alterations of Epigenetic Control in Premature Aging

The premature aging disease Hutchinson-Gilford Progeria Syndrome (HGPS) is caused by a mutant lamin A (LADelta50). Nuclei in cells expressing LADelta50 are abnormally shaped and display a loss of heterochromatin. To determine the mechanisms responsible for the loss of heterochromatin, epigenetic marks regulating either facultative or constitutive heterochromatin were examined. In cells from a female HGPS patient, histone H3 trimethylated on lysine 27 (H3K27me3), a mark for facultative heterochromatin, is lost on the inactive X chromosome (Xi). The methyltransferase responsible for this mark, EZH2, is also down-regulated. These alterations are detectable before the changes in nuclear shape that are considered to be the pathological hallmarks of HGPS cells. The results also show a down-regulation of the pericentric constitutive heterochromatin mark, histone H3 trimethylated on lysine 9, and an altered association of this mark with heterochromatin protein 1alpha (Hp1alpha) and the CREST antigen. This loss of constitutive heterochromatin is accompanied by an up-regulation of pericentric satellite III repeat transcripts. In contrast to these decreases in histone H3 methylation states, there is an increase in the trimethylation of histone H4K20, an epigenetic mark for constitutive heterochromatin. Expression of LADelta50 in normal cells induces changes in histone methylation patterns similar to those seen in HGPS cells. The epigenetic changes described most likely represent molecular mechanisms responsible for the rapid progression of premature aging in HGPS patients.

Endothelial Function in Post-menopausal Former Elite Athletes

To characterize endothelial function in postmenopausal former elite athletes in comparison to sedentary controls and to study the influence of hormone replacement therapy (HRT) on endothelial function in these groups of women.

Germ Line Insertions of Moloney Murine Leukemia Virus in the TLL Mouse Causes Site-specific Differences in Lymphoma/leukemia Frequency and Tumor Immunophenotype

Moloney murine leukemia virus (Mo-MLV) has proven valuable for studies of the pathogenesis of malignant lymphoma. Inoculation of newborn mice induces T cell lymphoma with 100% incidence. The TLL (T cell lymphoma/leukemia)-strain was previously established and was shown to spontaneously develop T cell lymphoma at high frequency.

Electromechanical Effects of Cardiac Resynchronization Therapy During Rest and Stress in Patients with Heart Failure

Haemodynamic and functional effects of cardiac resynchronization therapy (CRT) have been studied mostly at rest. CRT effects on left ventricular (LV) dyssynchrony and function during stress have not been evaluated in detail.

Characterization of Lamin Mutation Phenotypes in Drosophila and Comparison to Human Laminopathies

Lamins are intermediate filament proteins that make up the nuclear lamina, a matrix underlying the nuclear membrane in all metazoan cells that is important for nuclear form and function. Vertebrate A-type lamins are expressed in differentiating cells, while B-type lamins are expressed ubiquitously. Drosophila has two lamin genes that are expressed in A- and B-type patterns, and it is assumed that similarly expressed lamins perform similar functions. However, Drosophila and vertebrate lamins are not orthologous, and their expression patterns evolved independently. It is therefore of interest to examine the effects of mutations in lamin genes. Mutations in the mammalian lamin A/C gene cause a range of diseases, collectively called laminopathies, that include muscular dystrophies and premature aging disorders. We compared the sequences of lamin genes from different species, and we have characterized larval and adult phenotypes in Drosophila bearing mutations in the lam gene that is expressed in the B-type pattern. Larvae move less and show subtle muscle defects, and surviving lam adults are flightless and walk like aged wild-type flies, suggesting that lam phenotypes might result from neuromuscular defects, premature aging, or both. The resemblance of Drosophila lam phenotypes to human laminopathies suggests that some lamin functions may be performed by differently expressed genes in flies and mammals. Such still-unknown functions thus would not be dependent on lamin gene expression pattern, suggesting the presence of other lamin functions that are expression dependent. Our results illustrate a complex interplay between lamin gene expression and function through evolution.

On the Role of NR3A in Human NMDA Receptors

In the present paper we describe our on-going project investigating the functional roles of the N-methyl-D-aspartate (NMDA) receptor subunit NR3A. We find that NR3A mRNA is abundant both in embryonic and adult human brain, in contrast to the almost non-existing expression in adult rodent brain. Human NR3A (hNR3A) protein expression is particularly abundant in the cerebral cortex, as shown by western blot using NR3A-specific antibodies. Distribution of hNR3A in adult human brain shows a similar pattern as NR3A in post-natal rodent brain. We have previously reported that NR3A contains a glycine binding site, with similar affinity as the glycine binding site of NR1 subunits. This suggests that NR3A may replace one of the two NR1 subunits in native NMDA receptors. Cloning of hNR3A showed a human-specific polyproline-sequence in the intracellular C-terminus, that may bind to SH3-domains. We hypothesized that the significant differences in expression in the adult human and rodent brain could be due to an atypical interaction of hNR3A with the SH3 domain of the synaptic scaffolding protein PSD-95, that binds to NR2 subunits through its PDZ domains. However, using a number of different protein interaction assays, binding of PSD-95 to hNR3A could no be demonstrated either in vitro or in vivo. To identify intracellular signaling pathways for NR3A-containing NMDA receptors, we screened for proteins interacting with hNR3A and identified three proteins: plectin, CARP-1 and GPS2. The possible physiological roles of these interactions are discussed.

The NMDAR Subunit NR3A Interacts with Microtubule-associated Protein 1S in the Brain

When screening a brain cDNA library, we found that the N-methyl-D-aspartate receptor subunit NR3A binds to microtubule-associated protein (MAP) 1S/chromosome 19 open reading frame 5 (C19ORF5). The interaction was confirmed in vitro and in vivo, and binding of MAP1S was localized to the membrane-proximal part of the NR3A C-terminus. MAP1S belongs to the same family as MAP1A and MAP1B, and was found to be abundant in both postnatal and adult rat brain. In hippocampal neurons the distribution-pattern of MAP1S resembled that of beta-tubulin III, but a fraction of the protein colocalized with synaptic markers synapsin and postsynaptic density protein 95 (PSD95), in beta-tubulin III-negative filopodia-like protrusions. There was coexistance between MAP1S and NR3A immunoreactivity in neurite shafts and occasionally in filopodia-like processes. MAP1S potentially links NR3A to the cytoskeleton, and may stabilize NR3A-containing receptors at the synapse and regulate their movement between synaptic and extrasynaptic sites.

Decreased Flow-mediated Dilation is Present 1 Year After a Pre-eclamptic Pregnancy

Pre-eclamptic toxaemia is associated with inflammation and vascular endothelial dysfunction. As women who have had pre-eclamptic toxaemia are at an increased risk of cardiovascular disease, we hypothesized that these abnormalities are persistent.

Analysis of NR3A Receptor Subunits in Human Native NMDA Receptors

NR3A, representing the third class of NMDA receptor subunits, was first studied in rats, demonstrating ubiquitous expression in the developing central nervous system (CNS), but in the adult mainly expressed in spinal cord and some forebrain nuclei. Subsequent studies showed that rodent and non-human primate NR3A expression differs. We have studied the distribution of NR3A in the human CNS and show a widespread distribution of NR3A protein in adult human brain. NR3A mRNA and protein were found in all regions of the cerebral cortex, and also in the subcortical forebrain, midbrain and hindbrain. Only very low levels of NR3A mRNA and protein could be detected in homogenized adult human spinal cord, and in situ hybridization showed that expression was limited to ventral motoneurons. We found that NR3A is associated with NR1, NR2A and NR2B in adult human CNS, suggesting the existence of native NR1-NR2A/B-NR3A assemblies in adult human CNS. While NR1 and NR2A could only be efficiently solubilized by deoxycholate, NR3A was extracted by all detergents, suggesting that a large fraction is weakly anchored to cell membranes and other proteins. Using size exclusion chromatography we found that just as for NR1, a large fraction of NR3A exists as monomers and dimers, suggesting that these two glycine binding subunits behave similarly with regard to receptor assembly and trafficking.

Targeted Transgenic Expression of the Mutation Causing Hutchinson-Gilford Progeria Syndrome Leads to Proliferative and Degenerative Epidermal Disease

Hutchinson-Gilford progeria syndrome (HGPS) is a rare human genetic disorder characterized by striking progeroid features. Clinical findings in the skin include scleroderma, alopecia and loss of subcutaneous fat. HGPS is usually caused by a dominant-negative mutation in LMNA, a gene that encodes two major proteins of the inner nuclear lamina: lamin A and lamin C. We have generated tetracycline-inducible transgenic lines that carry a minigene of human LMNA under the control of a tet-operon. Two mouse lines were created: one carrying the wild-type sequence of LMNA and the other carrying the most common HGPS mutation. Targeted expression of the HGPS mutation in keratin-5-expressing tissues led to abnormalities in the skin and teeth, including fibrosis, loss of hypodermal adipocytes, structural defects in the hair follicles and sebaceous glands, and abnormal incisors. The severity of the defects was related to the level of expression of the transgene in different mouse lines. These transgenic mice appear to be good models for studies of the molecular mechanisms of skin abnormalities in HGPS and other related disorders.

Improved Fibrinolytic Activity During Exercise May Be an Effect of the Adipocyte-derived Hormones Leptin and Adiponectin

Physical activity is associated with improved fibrinolytic activity and reduced risk for cardiovascular disease. High levels of leptin and low levels of adiponectin, both adipocyte-derived hormones, or adipokines, are related to dysfibrinolysis and risk for cardiovascular disease. In this study, we explored if improved fibrinolytic activity during exercise could be linked to changes in leptin and adiponectin levels.

Effects of Cardiac Resynchronization Therapy on Coronary Blood Flow: Evaluation by Transthoracic Doppler Echocardiography

Relatively limited and conflicting data are available on the effects of cardiac resynchronization therapy (CRT) on coronary blood flow (CBF).

Cardiac Resynchronization Therapy During Rest and Exercise: Comparison of Two Optimization Methods

Optimal exercise programming of cardiac resynchronization therapy (CRT) devices is unknown. We aimed to: (i) investigate variations in optimal atrioventricular (AV) and interventricular (VV) delays from rest to exercise, assessed by both echocardiography and an automated intracardiac electrogram (IEGM) method; (ii) evaluate the acute haemodynamic impact of CRT optimization performed during exercise.

Sex-related Differences in the Associations Between Hyperleptinemia, Insulin Resistance and Dysfibrinolysis

The adipocyte-derived hormone leptin is associated with insulin resistance and reduced fibrinolytic status--or dysfibrinolysis--in humans. As leptin associates differentially to the development of cardiovascular disease and diabetes in men and women, we hypothesized that leptin and insulin sensitivity are related to dysfibrinolysis in a sex-dependent manner. Thirty-two men and 40 women were recruited from the Monitoring of trends and determinants in Cardiovascular disease (MONICA) population sample, representing the highest and lowest quartiles of fasting insulin levels. Lipids, fibrinolytic status [plasminogen activator inhibitor 1 (PAI-1) activity, tissue plasminogen activator (tPA) mass and activity, and tPA-PAI complex], leptin, testosterone and sex-hormone-binding globulin were measured. Insulin sensitivity was estimated using the euglycaemic clamp technique. Body composition was determined by bioimpedance. Determinants for circulating levels of fibrinolytic factors were explored in a multivariate linear regression analysis. Levels of fibrinolytic variables and estimated insulin sensitivity did not differ between men and women. Leptin was independently associated with reduced fibrinolytic status (high PAI-1 activity, low tPA activity, high tPA mass, and high tPA-PAI complex) in men (P < 0.001-0.002). In women, fat mass and/or insulin sensitivity were related to these factors (P < 0.001-0.03), and leptin only to reduced tPA activity (P = 0.002). Hyperleptinemia, dysfibrinolysis, insulin sensitivity and androgenicity associate differentially in men and women.

Left Atrial Velocity Vector Imaging for the Detection and Quantification of Left Ventricular Diastolic Function in Type 2 Diabetes

Left ventricular (LV) diastolic dysfunction (DD) is diagnosed by Doppler echocardiography (DE) and Tissue Doppler imaging (TDI). Velocity vector imaging (VVI) evaluates myocardial deformation (strain). We studied left atrial (LA) deformation and volumes by VVI in relation to established Doppler-derived indices of LV diastolic function in diabetic patients.

Differential Expression of A-type and B-type Lamins During Hair Cycling

Multiple genetic disorders caused by mutations that affect the proteins lamin A and C show strong skin phenotypes. These disorders include the premature aging disorders Hutchinson-Gilford progeria syndrome and mandibuloacral dysplasia, as well as restrictive dermopathy. Prior studies have shown that the lamin A/C and B proteins are expressed in skin, but little is known about their normal expression in the different skin cell-types and during the hair cycle. Our immunohistochemical staining for lamins A/C and B in wild-type mice revealed strong expression in the basal cell layer of the epidermis, the outer root sheath, and the dermal papilla during all stages of the hair cycle. Lower expression of both lamins A/C and B was seen in suprabasal cells of the epidermis, in the hypodermis, and in the bulb of catagen follicles. In addition, we have utilized a previously described mouse model of Hutchinson-Gilford progeria syndrome and show here that the expression of progerin does not result in pronounced effects on hair cycling or the expression of lamin B.

Increased Expression of the Hutchinson-Gilford Progeria Syndrome Truncated Lamin A Transcript During Cell Aging

Most cases of the segmental progeroid syndrome, Hutchinson-Gilford progeria syndrome (HGPS), are caused by a de novo dominant mutation within a single codon of the LMNA gene. This mutation leads to the increased usage of an internal splice site that generates an alternative lamin A transcript with an internal deletion of 150 nucleotides, called lamin A Delta 150. The LMNA gene encodes two major proteins of the inner nuclear lamina, lamins A and C, but not much is known about their expression levels. Determination of the overall expression levels of the LMNA gene transcripts is an important step to further the understanding of the HGPS. In this study, we have performed absolute quantification of the lamins A, C and A Delta 150 transcripts in primary dermal fibroblasts from HGPS patients and unaffected age-matched and parent controls. We show that the lamin A Delta 150 transcript is present in unaffected controls but its expression is >160-fold lower than that in samples from HGPS patients. Analysis of transcript expression during in vitro aging shows that although the levels of lamin A and lamin C transcripts remain unchanged, the lamin A Delta 150 transcript increases in late passage cells from HGPS patients and parental controls. This study provides a new method for LMNA transcript analysis and insights into the expression of the LMNA gene in HGPS and normal cells.

The Brichos Domain of Prosurfactant Protein C Can Hold and Fold a Transmembrane Segment

Prosurfactant protein C (proSP-C) is a 197-residue integral membrane protein, in which the C-terminal domain (CTC, positions 59-197) is localized in the endoplasmic reticulum (ER) lumen and contains a Brichos domain (positions 94-197). Mature SP-C corresponds largely to the transmembrane (TM) region of proSP-C. CTC binds to SP-C, provided that it is in nonhelical conformation, and can prevent formation of intracellular amyloid-like inclusions of proSP-C that harbor mutations linked to interstitial lung disease (ILD). Herein it is shown that expression of proSP-C (1-58), that is, the N-terminal propeptide and the TM region, in HEK293 cells results in virtually no detectable protein, while coexpression of CTC in trans yields SDS-soluble monomeric proSP-C (1-58). Recombinant human (rh) CTC binds to cellulose-bound peptides derived from the nonpolar TM region, but not the polar cytosolic part, of proSP-C, and requires >/=5-residues for maximal binding. Binding of rhCTC to a nonhelical peptide derived from SP-C results in alpha-helix formation provided that it contains a long TM segment. Finally, rhCTC and rhCTC Brichos domain shows very similar substrate specificities, but rhCTC(L188Q), a mutation linked to ILD is unable to bind all peptides analyzed. These data indicate that the Brichos domain of proSP-C is a chaperone that induces alpha-helix formation of an aggregation-prone TM region.

Multiple Vector Impedance Measurements During Biventricular Pacing: Feasibility and Possible Implications for Hemodynamic Monitoring

Intracardiac impedance (ICZ) has been known to reflect contractile capacity of the heart, and a strong relationship has been documented between stroke volume and ICZ. In this pilot study, conducted in heart failure patients during implantation of a biventricular device, we investigated acute changes in multiple vector ICZ signals during different pacing modes, and whether ICZ can be used to monitor hemodynamic variations.

Assessment of Left Ventricular Structure and Function in Preeclampsia by Echocardiography and Cardiovascular Biomarkers

To assess left ventricular (LV) structure and function in preeclampsia, a serious vascular-related pregnancy disorder, by Doppler tissue imaging (DTI) in combination with the levels of cardiovascular biomarkers.

Evidence for the Involvement of Lamins in Aging

The molecular mechanisms that cause physiological aging are still not completely understood, most likely because of the complex nature of the aging process. Recent discoveries on segmental progeroid syndromes emphasize the importance of studying rare diseases to discover more common mechanisms. Since the identification of mutations in the LMNA gene that causes the segmental progeroid syndrome, Hutchinson-Gilford progeria syndrome (HGPS), there has been an increasing interest in the potential role for lamins in the normal aging process. Recent data provide support for the shared mechanisms between natural and pathological aging, and show that further studies of HGPS and segmental progeroid syndromes will be of use in solving the aging puzzle. In this review, we summarize the recent findings and discuss the existing evidence for an important functional link between lamins and the aging process. In addition, we discuss the evidence for a mechanism in which defects in lamins result in genomic instability and senescence.

Alteration of PHYA Expression Change Circadian Rhythms and Timing of Bud Set in Populus

In many temperate woody species, dormancy is induced by short photoperiods. Earlier studies have shown that the photoreceptor phytochrome A (phyA) promotes growth. Specifically, Populus plants that over-express the oat PHYA gene (oatPHYAox) show daylength-independent growth and do not become dormant. However, we show that oatPHYAox plants could be induced to set bud and become cold hardy by exposure to a shorter, non-24 h diurnal cycle that significantly alters the relative position between endogenous rhythms and perceived light/dark cycles. Furthermore, we describe studies in which the expression of endogenous Populus tremula x P. tremuloides PHYTOCHROME A (PttPHYA) was reduced in Populus trees by antisense inhibition. The antisense plants showed altered photoperiodic requirements, resulting in earlier growth cessation and bud formation in response to daylength shortening, an effect that was explained by an altered innate period that leads to phase changes of clock-associated genes such as PttCO2. Moreover, gene expression studies following far-red light pulses show a phyA-mediated repression of PttLHY1 and an induction of PttFKF1 and PttFT. We conclude that the level of PttPHYA expression strongly influences seasonally regulated growth in Populus and is central to co-ordination between internal clock-regulated rhythms and external light/dark cycles through its dual effect on the pace of clock rhythms and in light signaling.

Changes in Diurnal Patterns Within the Populus Transcriptome and Metabolome in Response to Photoperiod Variation

Changes in seasonal photoperiod provides an important environmental signal that affects the timing of winter dormancy in perennial, deciduous, temperate tree species, such as hybrid aspen (Populus tremula x Populus tremuloides). In this species, growth cessation, cold acclimation and dormancy are induced in the autumn by the detection of day-length shortening that occurs at a given critical day length. Important components in the detection of such day-length changes are photoreceptors and the circadian clock, and many plant responses at both the gene regulation and metabolite levels are expected to be diurnal. To directly examine this expectation and study components in these events, here we report transcriptomic and metabolomic responses to a change in photoperiod from long to short days in hybrid aspen. We found about 16% of genes represented on the arrays to be diurnally regulated, as assessed by our pre-defined criteria. Furthermore, several of these genes were involved in circadian-associated processes, including photosynthesis and primary and secondary metabolism. Metabolites affected by the change in photoperiod were mostly involved in carbon metabolism. Taken together, we have thus established a molecular catalog of events that precede a response to winter.

MAP1B Binds to the NMDA Receptor Subunit NR3A and Affects NR3A Protein Concentrations

Incorporation of the N-methyl-d-aspartate receptor (NMDAR) subunit NR3A into functional NMDARs results in reduced channel conductance and Ca(2+) permeability. To further investigate the function of NR3A, we have set out to characterize its intracellular binding partners. Here, we report a novel protein interaction between NR3A and microtubule associated-protein (MAP) 1B, which both are localized to dendritic shafts and filopodia. NR3A protein levels were increased in MAP1B deficient (-/-) mice, with a corresponding decrease in NR1 levels, but the fraction of filopodia immunoreactive for NR3A was equal in cells from -/- and wild type (WT) mice. NR3A has previously been shown to interact with another member of the MAP1 family, MAP1S. We showed that MAP1S binds to microtubules in a similar manner as MAP1B, and suggest that MAP1S and MAP1B both are involved in regulating trafficking of NR3A-containing NMDAR.

Circadian Clock Components Regulate Entry and Affect Exit of Seasonal Dormancy As Well As Winter Hardiness in Populus Trees

This study addresses the role of the circadian clock in the seasonal growth cycle of trees: growth cessation, bud set, freezing tolerance, and bud burst. Populus tremula x Populus tremuloides (Ptt) LATE ELONGATED HYPOCOTYL1 (PttLHY1), PttLHY2, and TIMING OF CAB EXPRESSION1 constitute regulatory clock components because down-regulation by RNA interference of these genes leads to altered phase and period of clock-controlled gene expression as compared to the wild type. Also, both RNA interference lines show about 1-h-shorter critical daylength for growth cessation as compared to the wild type, extending their period of growth. During winter dormancy, when the diurnal variation in clock gene expression stops altogether, down-regulation of PttLHY1 and PttLHY2 expression compromises freezing tolerance and the expression of C-REPEAT BINDING FACTOR1, suggesting a role of these genes in cold hardiness. Moreover, down-regulation of PttLHY1 and PttLHY2 causes a delay in bud burst. This evidence shows that in addition to a role in daylength-controlled processes, PttLHY plays a role in the temperature-dependent processes of dormancy in Populus such as cold hardiness and bud burst.

Magnetic Resonance Imaging and Ultrasonography in Diagnosis of Pelvic Vein Thrombosis During Pregnancy

Pelvic deep vein thrombosis (DVT) is difficult to diagnose during pregnancy. In a two-center trial, we evaluated the agreement between ultrasonography and magnetic resonance imaging (MRI) in diagnosing the extent of DVT into the pelvic veins during pregnancy.

Polycomb Target Genes Are Silenced in Multiple Myeloma

Multiple myeloma (MM) is a genetically heterogeneous disease, which to date remains fatal. Finding a common mechanism for initiation and progression of MM continues to be challenging. By means of integrative genomics, we identified an underexpressed gene signature in MM patient cells compared to normal counterpart plasma cells. This profile was enriched for previously defined H3K27-tri-methylated genes, targets of the Polycomb group (PcG) proteins in human embryonic fibroblasts. Additionally, the silenced gene signature was more pronounced in ISS stage III MM compared to stage I and II. Using chromatin immunoprecipitation (ChIP) assay on purified CD138+ cells from four MM patients and on two MM cell lines, we found enrichment of H3K27me3 at genes selected from the profile. As the data implied that the Polycomb-targeted gene profile would be highly relevant for pharmacological treatment of MM, we used two compounds to chemically revert the H3K27-tri-methylation mediated gene silencing. The S-adenosylhomocysteine hydrolase inhibitor 3-Deazaneplanocin (DZNep) and the histone deacetylase inhibitor LBH589 (Panobinostat), reactivated the expression of genes repressed by H3K27me3, depleted cells from the PRC2 component EZH2 and induced apoptosis in human MM cell lines. In the immunocompetent 5T33MM in vivo model for MM, treatment with LBH589 resulted in gene upregulation, reduced tumor load and increased overall survival. Taken together, our results reveal a common gene signature in MM, mediated by gene silencing via the Polycomb repressor complex. The importance of the underexpressed gene profile in MM tumor initiation and progression should be subjected to further studies.

Radionuclide Angiographic Determination of Regional Left Ventricular Systolic Function During Rest and Exercise in Patients with Nonischemic Cardiomyopathy Treated with Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) can improve global left ventricular (LV) function. However, limited data are available on regional LV contractility at rest and during exercise. The aim of the present study was to prospectively investigate the effects of CRT on regional LV ejection fraction (EF), global LVEF, and dyssynchrony, during rest and exercise, using radionuclide angiography. A total of 32 consecutive patients with heart failure and nonischemic cardiomyopathy underwent technetium-99m radionuclide angiography with bicycle exercise immediately after CRT implantation (during spontaneous rhythm and after CRT activation) and 3 months later. The regional EF was assessed in the interventricular septum and the lateral wall (LW). Intraventricular dyssynchrony was evaluated using Fourier phase analysis. During spontaneous rhythm, the EF was severely depressed in the septum compared to in the LW. CRT improved septal EF at rest and during exercise both at baseline (p <0.001) and after 3 months (p <0.05). The basal LW EF decreased during CRT (p <0.05, both at rest and during exercise). LV dyssynchrony decreased both at baseline and during follow-up, and the global LVEF showed improvement only at 3 months (p <0.001). In conclusion, in patients with nonischemic cardiomyopathy, CRT affects regional LV function by increasing the septal EF and reducing LW contractility, both at rest and during exercise. This was associated with an improvement in global LVEF and dyssynchrony.

The Feasibility of Velocity Vector Imaging by Transesophageal Echocardiography for Assessment of Elastic Properties of the Descending Aorta in Aortic Valve Disease

Velocity vector imaging (VVI) is a novel two-dimensional speckle-based imaging technique for evaluation of tissue deformation. The aim of this study was to determine the feasibility and variability of VVI for the assessment of aortic strain, distensibility, and stiffness in patients with aortic valve disease.

Endothelin-1 and Brain Natriuretic Peptide Plasma Levels Decrease After Aortic Surgery

Endothelin-1 (ET-1) and B-type natriuretic peptide (BNP) have been reported to be involved in numerous cardiovascular diseases. The study aim was to monitor the circulating plasma levels of these peptides in patients affected by aortic disease, and to identify any changes in such levels after surgical treatment.

Impaired Splicing of Fibronectin is Associated with Thoracic Aortic Aneurysm Formation in Patients with Bicuspid Aortic Valve

Thoracic aortic aneurysm is a common complication in patients with bicuspid aortic valve (BAV). Alternatively spliced extra domain A (EDA) of fibronectin (FN) has an essential role in tissue repair. Here we analyze the expression of FN spliceforms in dilated and nondilated ascending aorta of tricuspid aortic valve (TAV) and BAV patients.

Health Effects on Leaders and Co-workers of an Art-based Leadership Development Program

There are very few evaluations of the effectiveness of leadership development programs. The purpose of the study was to examine whether an art-based leadership program may have a more beneficial effect than a conventional one on leaders' and their corresponding subordinates' mental and biological stress.

Effects of Cardiac Resynchronization Therapy on Myocardial Contractile Reserve During Exercise

Myocardial contractile reserve (MCR) is a marker of myocardial viability. The impact of cardiac resynchronization therapy (CRT) on MCR during exercise has been little studied. Our aim was to investigate the effects of CRT on global and regional MCR by exercise echocardiography.

Partners in Time: EARLY BIRD Associates with ZEITLUPE and Regulates the Speed of the Arabidopsis Clock

The circadian clock of the model plant Arabidopsis (Arabidopsis thaliana) is made up of a complex series of interacting feedback loops whereby proteins regulate their own expression across day and night. early bird (ebi) is a circadian mutation that causes the clock to speed up: ebi plants have short circadian periods, early phase of clock gene expression, and are early flowering. We show that EBI associates with ZEITLUPE (ZTL), known to act in the plant clock as a posttranslational mediator of protein degradation. However, EBI is not degraded by its interaction with ZTL. Instead, ZTL counteracts the effect of EBI during the day and increases it at night, modulating the expression of key circadian components. The partnership of EBI with ZTL reveals a novel mechanism involved in controlling the complex transcription-translation feedback loops of the clock. This work highlights the importance of cross talk between the ubiquitination pathway and transcriptional control for regulation of the plant clock.

Upregulation of the 5-lipoxygenase Pathway in Human Aortic Valves Correlates with Severity of Stenosis and Leads to Leukotriene-induced Effects on Valvular Myofibroblasts

The development of aortic valve stenosis is not only associated with calcification and extracellular matrix remodeling, but also with inflammation. The aim of this study was to determine the role of proinflammatory signaling through the leukotriene (LT) pathway in aortic stenosis.

Full Genome Re-sequencing Reveals a Novel Circadian Clock Mutation in Arabidopsis

Map based cloning in Arabidopsis thaliana can be a difficult and time-consuming process, specifically if the phenotype is subtle and scoring labour intensive. Here, we have re-sequenced the 120-Mb genome of a novel Arabidopsis clock mutant early bird (ebi-1) in Wassilewskija (Ws-2). We demonstrate the utility of sequencing a backcrossed line in limiting the number of SNPs considered. We identify a SNP in the gene AtNFXL-2 as the likely cause of the ebi-1 phenotype.

Long-term Outcome of Percutaneous Transluminal Septal Myocardial Ablation in Hypertrophic Obstructive Cardiomyopathy: a Scandinavian Multicenter Study

Single-center reports on percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy have shown considerable differences in outcome.

Delegation Within Municipal Health Care

To describe how registered nurses (RNs) perceive delegation to unlicensed personnel (UP) in a municipal healthcare context in Sweden.

Bicuspid Aortic Valve Leaflet Morphology in Relation to Aortic Root Morphology: a Study of 300 Patients Undergoing Open-heart Surgery

There is an ongoing discussion regarding the mechanism of aortic dilatation in bicuspid aortic valve (BAV) disease, that is, is this a hemodynamic effect or related to an inborn weakness of the aortic wall? This study evaluated the possibility of BAV morphology being related to ascending aorta morphology as such a correlation would strengthen the idea that hemodynamic alterations cause the dilatation of the aorta.

A Previously Functional Tetracycline-regulated Transactivator Fails to Target Gene Expression to the Bone

The tetracycline-controlled transactivator system is a powerful tool to control gene expression in vitro and to generate consistent and conditional transgenic in vivo model organisms. It has been widely used to study gene function and to explore pathological mechanisms involved in human diseases. The system permits the regulation of the expression of a target gene, both temporally and quantitatively, by the application of tetracycline or its derivative, doxycycline. In addition, it offers the possibility to restrict gene expression in a spatial fashion by utilizing tissue-specific promoters to drive the transactivator.

Stem Cell Depletion in Hutchinson-Gilford Progeria Syndrome

Hutchinson-Gilford progeria syndrome (HGPS or progeria) is a very rare genetic disorder with clinical features suggestive of premature aging. Here, we show that induced expression of the most common HGPS mutation (LMNA c.1824C>T, p.G608G) results in a decreased epidermal population of adult stem cells and impaired wound healing in mice. Isolation and growth of primary keratinocytes from these mice demonstrated a reduced proliferative potential and ability to form colonies. Downregulation of the epidermal stem cell maintenance protein p63 with accompanying activation of DNA repair and premature senescence was the probable cause of this loss of adult stem cells. Additionally, upregulation of multiple genes in major inflammatory pathways indicated an activated inflammatory response. This response has also been associated with normal aging, emphasizing the importance of studying progeria to increase the understanding of the normal aging process.

Plant Cell Responses to Cold Are All About Timing

Changes in temperature present the cells of plants with particular challenges. Fortunately, many changes in temperature can be anticipated due to the rhythms of day/night and the seasons. To anticipate changes in the environment most organisms have a circadian clock to optimize daily and seasonal timing of gene expression, metabolism, physiology and cell biology. Circadian clocks comprised positive and negative feedback loops which ensure an internal period of approximately 24 hours. We describe the role of the circadian clock in modulating cellular cold signalling networks to prepare the cell for the onset of winter.

Unraveling Divergent Gene Expression Profiles in Bicuspid and Tricuspid Aortic Valve Patients with Thoracic Aortic Dilatation: the ASAP Study

Thoracic aortic aneurysm (TAA) is a common complication in patients with a bicuspid aortic valve (BAV), the most frequent congenital heart disorder. For unknown reasons TAA occurs at a younger age, with a higher frequency in BAV patients than in patients with a tricuspid aortic valve (TAV), resulting in an increased risk for aortic dissection and rupture. To investigate the increased TAA incidence in BAV patients, we obtained tissue biopsy samples from nondilated and dilated aortas of 131 BAV and TAV patients. Global gene expression profiles were analyzed from controls and from aortic intima-media and adventitia of patients (in total 345 samples). Of the genes found to be differentially expressed with dilation, only a few (<4%) were differentially expressed in both BAV and TAV patients. With the use of gene set enrichment analysis, the cell adhesion and extracellular region gene ontology sets were identified as common features of TAA in both BAV and TAV patients. Immune response genes were observed to be particularly overexpressed in the aortic media of dilated TAV samples. The divergent gene expression profiles indicate that there are fundamental differences in TAA etiology in BAV and TAV patients. Immune response activation solely in the aortic media of TAV patients suggests that inflammation is involved in TAA formation in TAV but not in BAV patients. Conversely, genes were identified that were only differentially expressed with dilation in BAV patients. The result has bearing on future clinical studies in which separate analysis of BAV and TAV patients is recommended.

Low and High Expressing Alleles of the LMNA Gene: Implications for Laminopathy Disease Development

Today, there are at least a dozen different genetic disorders caused by mutations within the LMNA gene, and collectively, they are named laminopathies. Interestingly, the same mutation can cause phenotypes with different severities or even different disorders and might, in some cases, be asymptomatic. We hypothesized that one possible contributing mechanism for this phenotypic variability could be the existence of high and low expressing alleles in the LMNA locus. To investigate this hypothesis, we developed an allele-specific absolute quantification method for lamin A and lamin C transcripts using the polymorphic rs4641(C/T)LMNA coding SNP. The contribution of each allele to the total transcript level was investigated in nine informative human primary dermal fibroblast cultures from Hutchinson-Gilford progeria syndrome (HGPS) and unaffected controls. Our results show differential expression of the two alleles. The C allele is more frequently expressed and accounts for ∼70% of the lamin A and lamin C transcripts. Analysis of samples from six patients with Hutchinson-Gilford progeria syndrome showed that the c.1824C>T, p.G608G mutation is located in both the C and the T allele, which might account for the variability in phenotype seen among HGPS patients. Our method should be useful for further studies of human samples with mutations in the LMNA gene and to increase the understanding of the link between genotype and phenotype in laminopathies.

Myocardial Recovery in Peri-partum Cardiomyopathy After Continuous Flow Left Ventricular Assist Device

Left ventricular assist devices (LVADs) offer effective therapy for severe heart failure (HF) as bridge to transplantation or destination therapy. Rarely, the sustained unloading provided by the LVAD has led to cardiac reverse remodelling and recovery, permitting explantation of the device. We describe the clinical course of a patient with severe peri-partum cardiomyopathy (PPCM) rescued with a continuous flow LVAD, who experienced recovery and explantation. We discuss assessment of and criteria for recovery.

Impaired Endothelial Function and Elevated Levels of Pentraxin 3 in Early-onset Preeclampsia

To study endothelial function in relation to anti-angiogenic biomarkers and the inflammatory process in preeclampsia.

Derived and Displayed Power Consumption, Flow, and Pulsatility over a Range of HeartMate II Left Ventricular Assist Device Settings

Continuous-flow left ventricular assist devices/systems (LVADs/LVASs) reduce symptoms and mortality in severe heart failure. The impeller or centrifugal designs provide challenges in assessing and titrating pump speed (revolutions per minute [RPM]), flow, and native heart pulsatility, and contribution to cardiac output. The Thoratec HeartMate II (HM II) LVAS is the most commonly used LVAD worldwide. The user sets the RPM and the monitor provides online data on RPM, power consumption, flow, and pulsatility. These parameters are routinely used by clinicians to assess native heart function and to optimize pump settings. However, little is known about their reliability, reproducibility, and variability. Therefore, we assessed HM II controller parameters and concurrent echocardiography during titrations of RPM to low and high values. We found that data displayed on the monitor and logged in the controller are consistent for power consumption and for flow at settings above 8,000 RPM but inconsistent and unreliable for flow at or below 8,000 RPM and for pulsatility throughout a range of common settings and specifically at 9,000 RPM. These findings have implications for clinicians attempting to optimize settings and assess pump and native heart function.

The Dynamic Nature of Bud Dormancy in Trees: Environmental Control and Molecular Mechanisms

In tree species native to temperate and boreal regions, the activity-dormancy cycle is an important adaptive trait both for survival and growth. We discuss recent research on mechanisms controlling the overlapping developmental processes that define the activity-dormancy cycle, including cessation of apical growth, bud development, induction, maintenance and release of dormancy, and bud burst. The cycle involves an extensive reconfiguration of metabolism. Environmental control of the activity-dormancy cycle is based on perception of photoperiodic and temperature signals, reflecting adaptation to prevailing climatic conditions. Several molecular actors for control of growth cessation have been identified, with the CO/FT regulatory network and circadian clock having important coordinating roles in control of growth and dormancy. Other candidate regulators of bud set, dormancy and bud burst have been identified, such as dormancy-associated MADS-box factors, but their exact roles remain to be discovered. Epigenetic mechanisms also appear to factor in control of the activity-dormancy cycle. Despite evidence for gibberellins as negative regulators in growth cessation, and ABA and ethylene in bud formation, understanding of the roles that plant growth regulators play in controlling the activity-dormancy cycle is still very fragmentary. Finally, some of the challenges for further research in bud dormancy are discussed.

Changes in Global Longitudinal Strain During Rest and Exercise in Patients Treated with Cardiac Resynchronization Therapy

Relatively few data have been reported on prospective changes in global longitudinal strain (GLS) following cardiac resynchronization therapy (CRT), and none are available on GLS during physical exercise. We investigated the effects of CRT on GLS, assessed by speckle tracking two-dimensional (2D) echocardiography, at rest and during exercise after a mid-term follow-up. Twenty consecutive CRT patients (45% ischaemic) were assessed prospectively by speckle tracking 2D echocardiography before implant (at rest) and at mid-term follow-up (during rest and bicycle exercise). GLS, septum and lateral wall longitudinal strain, left ventricular ejection fraction (LVEF), and conventional functional variables were evaluated at baseline and follow-up. All patients completed the study protocol at rest. Exercise images were available in 90% of the patients. At follow-up, GLS improved at rest from -7.1 ± 2.6% to -9.1 ± 4.5% (P<0.01), with a further increase to -11 ± 5.1% during exercise (P<0.001). Longitudinal strain increased at rest both in the septum and in the lateral wall, with an additional increase during exercise in the lateral wall (P<0.05). GLS correlated with LVEF both at rest (r= -0.55 and r= -0.91 at baseline and 3 months, respectively; P<0.05) and during exercise (r= -0.89, P<0.05). Improvement in GLS during rest and exercise can be observed in CRT patients at mid-term follow-up and seems to correlate with changes in LVEF. GLS may be a valuable method to assess left ventricular function during rest and exercise.

Arterial Structure and Function in Mild Primary Hyperparathyroidism is Not Directly Related to Parathyroid Hormone, Calcium, or Vitamin D

Elevated levels of calcium and parathyroid hormone (PTH), characteristics of primary hyperparathyroidism (PHPT), may be associated with cardiovascular morbidity and mortality in the general population. We evaluated the possible vascular effects of these risk factors in patients with mild PHPT by using standard methods and new imaging techniques.

A Simple and Efficient Transient Transformation for Hybrid Aspen (Populus Tremula × P. Tremuloides)

The genus Populus is accepted as a model system for molecular tree biology. To investigate gene functions in Populus spp. trees, generating stable transgenic lines is the common technique for functional genetic studies. However, a limited number of genes have been targeted due to the lengthy transgenic process. Transient transformation assays complementing stable transformation have significant advantages for rapid in vivo assessment of gene function. The aim of this study is to develop a simple and efficient transient transformation for hybrid aspen and to provide its potential applications for functional genomic approaches.

Expression of the Hutchinson-Gilford Progeria Mutation During Osteoblast Development Results in Loss of Osteocytes, Irregular Mineralization, and Poor Biomechanical Properties

Hutchinson-Gilford progeria syndrome (HGPS) is a very rare genetic disorder that is characterized by multiple features of premature aging and largely affects tissues of mesenchymal origin. In this study, we describe the development of a tissue-specific mouse model that overexpresses the most common HGPS mutation (LMNA, c.1824C>T, p.G608G) in osteoblasts. Already at the age of 5 weeks, HGPS mutant mice show growth retardation, imbalanced gait and spontaneous fractures. Histopathological examination revealed an irregular bone structure, characterized by widespread loss of osteocytes, defects in mineralization, and a hypocellular red bone marrow. Computerized tomography analysis demonstrated impaired skeletal geometry and altered bone structure. The skeletal defects, which resemble the clinical features reported for bone disease in HGPS patients, was associated with an abnormal osteoblast differentiation. The osteoblast-specific expression of the HGPS mutation increased DNA damage and affected Wnt signaling. In the teeth, irregular dentin formation, as was previously demonstrated in human progeria cases, caused severe dental abnormalities affecting the incisors. The observed phenotype also shows similarities to reported bone abnormalities in aging mice and may therefore help to uncover general principles of the aging process.

Real-time Imaging Required for Optimal Echocardiographic Assessment of Aortic Valve Calcification

Aortic valve calcification (AVC), even without haemodynamic significance, may be prognostically import as an expression of generalized atherosclerosis, but techniques for echocardiographic assessment are essentially unexplored.

Waiting
simple hit counter