PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (30)
 

Clipboard (0)
None

Select a Filter Below

Year of Publication
1.  Whole Blood Transcriptional Profiling Reveals Deregulation of Oxidative and Antioxidative Defence Genes in Myelofibrosis and Related Neoplasms. Potential Implications of Downregulation of Nrf2 for Genomic Instability and Disease Progression 
PLoS ONE  2014;9(11):e112786.
The Philadelphia-negative chronic myeloproliferative neoplasms - essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) (MPNs) - have recently been shown to be associated with chronic inflammation, oxidative stress and accumulation of reactive oxygen species (ROS). Using whole blood transcriptional profiling, we report that several oxidative stress and anti-oxidative stress genes are significantly deregulated in MPNs. Among the twenty most up- and downregulated genes, ATOX1, DEFB122, GPX8, PRDX2, PRDX6, PTGS1, and SEPP1 were progressively upregulated from ET over PV to PMF, whereas AKR1B1, CYBA, SIRT2, TTN, and UCP2 were progressively downregulated in ET, PV and PMF (all FDR <0.05). The gene Nrf2, encoding the transcription factor nuclear factor erythroid 2-related factor 2 (NFE2L2 or Nrf2) was significantly downregulated in all MPNs. Nrf2 has a key role in the regulation of the oxidative stress response and modulates both migration and retention of hematopoietic stem cells (HSCs) in their niche. The patogenetic importance of Nrf2 depletion in the context of expansion of the hematopoietic progenitor pool in MPNs is discussed with particular focus upon the implications of concomitant downregulation of Nrf2 and CXCR4 for stem cell mobilization.
doi:10.1371/journal.pone.0112786
PMCID: PMC4232509  PMID: 25397683
2.  The ZFP-1(AF10)/DOT-1 Complex Opposes H2B Ubiquitination to Reduce Pol II Transcription 
Molecular cell  2013;50(6):894-907.
SUMMARY
The inhibition of transcriptional elongation plays an important role in gene regulation in metazoans, including C. elegans. Here, we combine genomic and biochemical approaches to dissect a role of ZFP-1, the C. elegans AF10 homolog, in transcriptional control. We show that ZFP-1 and its interacting partner DOT-1.1 have a global role in negatively modulating the level of polymerase II (Pol II) transcription on essential widely expressed genes. Moreover, the ZFP-1/DOT-1.1 complex contributes to progressive Pol II pausing on essential genes during development and to rapid Pol II pausing during stress response. The slowing down of Pol II transcription by ZFP-1/DOT-1.1 is associated with an increase in H3K79 methylation and a decrease in H2B monoubiquitination, which promotes transcription. We propose a model wherein the recruitment of ZFP-1/DOT-1.1 and deposition of H3K79 methylation at highly expressed genes initiates a negative feedback mechanism for the modulation of their expression.
doi:10.1016/j.molcel.2013.06.002
PMCID: PMC3784254  PMID: 23806335
3.  Ensiling and hydrothermal pretreatment of grass: consequences for enzymatic biomass conversion and total monosaccharide yields 
Background
Ensiling may act as a pretreatment of fresh grass biomass and increase the enzymatic conversion of structural carbohydrates to fermentable sugars. However, ensiling does not provide sufficient severity to be a standalone pretreatment method. Here, ensiling of grass is combined with hydrothermal treatment (HTT) with the aim of improving the enzymatic biomass convertibility and decrease the required temperature of the HTT.
Results
Grass silage (Festulolium Hykor) was hydrothermally treated at temperatures of 170, 180, and 190°C for 10 minutes. Relative to HTT treated dry grass, ensiling increased the solubilization of dry matter (DM) during HTT and gave increased glucan content, but lower lignin in the insoluble fiber fraction. Ensiling improved glucose yields in the enzymatic hydrolysis of the washed solid fiber fraction at the lower HTT temperatures. At 170°C glucose yield improved from 17 to 24 (w/w)% (45 to 57% cellulose convertibility), and at 180°C glucose yield improved from 22 to 29 (w/w)% (54 to 69% cellulose convertibility). Direct HTT of grass at 190°C gave the same high glucose yield as for grass silage (35 (w/w)% (77% cellulose convertibility)) and improved xylan yields (27% xylan convertibility). The effect of ensiling of grass prior to HTT improved the enzymatic conversion of cellulose for HTT at 170 and 180°C, but the increased glucose release did not make up for the loss of water soluble carbohydrates (WSC) during ensiling. Overall, sugar yields (C6 + C5) were similar for HTT of grass and grass silage at both 170 and 180°C, but at 190°C the overall sugar yield was better for HTT of dry grass.
Conclusions
This study unequivocally establishes that ensiling of grass as a biomass pretreatment method comes with a loss of WSC. The loss of WSC by ensiling is not necessarily compensated for by providing a lower temperature requirement for HTT for high enzymatic monosaccharide release. However, ensiling can be an advantageous storage method prior to grass processing.
doi:10.1186/1754-6834-7-95
PMCID: PMC4096529  PMID: 25024743
Silage; Ensiling; Combined pretreatment; Hydrothermal treatment; Grass; Enzymatic hydrolysis
4.  Predictors for an unsuccessful INtubation-SURfactant-Extubation procedure: a cohort study 
BMC Pediatrics  2014;14:155.
Background
The INtubation-SURfactant-Extubation (INSURE) is a procedure that is increasingly being used to treat the respiratory distress syndrome in preterm infants. The objective of this study was to identify predictors for an unsuccessful INSURE procedure.
Methods
The neonates included were less than 32 weeks’ gestation, treated with surfactant in the neonatal intensive care unit, and born 1998–2010. INSURE was defined as surfactant administration during intubation for less than 2 hours without the need for mechanical ventilation. INSURE success was defined as no re-intubation within 72 hours after INSURE, and INSURE failure was defined as re-intubation within 72 hours after INSURE. An unsuccessful INSURE procedure was either INSURE failure or mechanical ventilation for more than 24 hours immediately after surfactant administration. All predictors were defined a priori and were present before surfactant administration. Multivariate logistic regression was performed.
Results
In total, 322 neonates were included: 31% (n = 100) had INSURE success, 10% (n = 33) had INSURE failure, 49% (n = 158) needed mechanical ventilation for more than 24 hours, and the remaining 10% (n = 31) needed mechanical ventilation for less than 24 hours. Predictors for INSURE failure were low gestational age and hemoglobin below 8.5 mmol/l. Predictors for mechanical ventilation for more than 24 hours were low gestational age, Apgar at 5 minutes below 7, oxygen need above 50%, CO2 pressure above 7 kPa (~53 mmHg), pH below 7.3, lactate above 2.5 mmol/l, need for inotropes, and surfactant administration shortly after birth, whereas preeclampsia reduced the risk.
Conclusions
We identified specific predictors associated with an unsuccessful INSURE procedure. Keeping high-risk neonates with one or several predictors intubated and treated with mechanical ventilation after surfactant may prevent a re-intubation procedure.
doi:10.1186/1471-2431-14-155
PMCID: PMC4072617  PMID: 24947477
Respiratory distress syndrome; Pulmonary surfactants; Premature neonates; Mechanical ventilation; Continuous positive airway pressure
5.  Socio-occupational class, region of birth and maternal age: influence on time to detection of cryptorchidism (undescended testes): a Danish nationwide register study 
BMC Urology  2014;14:23.
Background
Cryptorchidism (undescended testes) is associated with poor male fertility, but can be alleviated and fertility preserved to some degree by early detection and treatment. Here we assess the influence of socio-occupational class, geographical region, maternal age and birth cohort on time to detection and correction of cryptorchidism.
Methods
All boys born in Denmark, 1981 to 1987 or 1988 to 1994, with a diagnosis of cryptorchidism were identified in nationwide registers. The boys were followed for a diagnosis until their 16th birthday. The age at first diagnosis was noted and used as proxy for time to detection of cryptorchidism. Parental employment in the calendar year preceding birth was grouped into one of five socio-occupational classes. Geographical region was defined by place of birth in one of 15 Danish counties. Detection rate ratios of cryptorchidism were analyzed as a function of parental socio-occupational group, county, maternal age and birth cohort by use of Poisson regression.
Results
Some 6,059 boys in the early and 5,947 boys in the late cohort received a diagnosis of cryptorchidism. Time to detection was independent of parental socio-occupational group and maternal age but differed slightly between geographical regions. A similar pattern was obtained for surgical correction after a diagnosis. Age at diagnosis decreased by 2.7 years from the early to the late cohort.
Conclusions
These results indicate that childhood socio-occupational inequality in detection and correction of cryptorchidism would play a negligible role in male infertility in a life course perspective. Geographical region may have exerted some influence, especially for the oldest cohort.
doi:10.1186/1471-2490-14-23
PMCID: PMC4016268  PMID: 24581337
Cryptorchidism; Fertility; Diagnosis; Orchiopexy; Geography; Register; Public health
6.  Transcriptional Profiling of Whole Blood Identifies a Unique 5-Gene Signature for Myelofibrosis and Imminent Myelofibrosis Transformation 
PLoS ONE  2014;9(1):e85567.
Identifying a distinct gene signature for myelofibrosis may yield novel information of the genes, which are responsible for progression of essential thrombocythemia and polycythemia vera towards myelofibrosis. We aimed at identifying a simple gene signature – composed of a few genes - which were selectively and highly deregulated in myelofibrosis patients. Gene expression microarray studies have been performed on whole blood from 69 patients with myeloproliferative neoplasms. Amongst the top-20 of the most upregulated genes in PMF compared to controls, we identified 5 genes (DEFA4, ELA2, OLFM4, CTSG, and AZU1), which were highly significantly deregulated in PMF only. None of these genes were significantly regulated in ET and PV patients. However, hierarchical cluster analysis showed that these genes were also highly expressed in a subset of patients with ET (n = 1) and PV (n = 4) transforming towards myelofibrosis and/or being featured by an aggressive phenotype. We have identified a simple 5-gene signature, which is uniquely and highly significantly deregulated in patients in transitional stages of ET and PV towards myelofibrosis and in patients with PMF only. Some of these genes are considered to be responsible for the derangement of bone marrow stroma in myelofibrosis. Accordingly, this gene-signature may reflect key processes in the pathogenesis and pathophysiology of myelofibrosis development.
doi:10.1371/journal.pone.0085567
PMCID: PMC3890316  PMID: 24454890
7.  Professional Continuous Glucose Monitoring in Subjects with Type 1 Diabetes: Retrospective Hypoglycemia Detection 
Background
An important task in diabetes management is detection of hypoglycemia. Professional continuous glucose monitoring (CGM), which produces a glucose reading every 5 min, is a powerful tool for retrospective identification of unrecognized hypoglycemia. Unfortunately, CGM devices tend to be inaccurate, especially in the hypoglycemic range, which limits their applicability for hypoglycemia detection. The objective of this study was to develop an automated pattern recognition algorithm to detect hypoglycemic events in retrospective, professional CGM.
Methods
Continuous glucose monitoring and plasma glucose (PG) readings were obtained from 17 data sets of 10 type 1 diabetes patients undergoing insulin-induced hypoglycemia. The CGM readings were automatically classified into a hypoglycemic group and a nonhypoglycemic group on the basis of different features from CGM readings and insulin injection. The classification was evaluated by comparing the automated classification with PG using sample-based and event-based sensitivity and specificity measures.
Results
With an event-based sensitivity of 100%, the algorithm produced only one false hypoglycemia detection. The sample-based sensitivity and specificity levels were 78% and 96%, respectively.
Conclusions
The automated pattern recognition algorithm provides a new approach for detecting unrecognized hypoglycemic events in professional CGM data. The tool may assist physicians and diabetologists in conducting a more thorough evaluation of the diabetes patient’s glycemic control and in initiating necessary measures for improving glycemic control.
PMCID: PMC3692225  PMID: 23439169
continuous glucose monitoring; diabetes; hypoglycemia; machine learning; retrospective
8.  The Wobbler Mouse Model of Amyotrophic Lateral Sclerosis (ALS) Displays Hippocampal Hyperexcitability, and Reduced Number of Interneurons, but No Presynaptic Vesicle Release Impairments 
PLoS ONE  2013;8(12):e82767.
Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. It is a fatal degenerative disease, best recognized for its debilitating neuromuscular effects. ALS however also induces cognitive impairments in as many as 50% of affected individuals. Moreover, many ALS patients demonstrate cortical hyperexcitability, which has been shown to precede the onset of clinical symptoms. The wobbler mouse is a model of ALS, and like ALS patients the wobbler mouse displays cortical hyperexcitability. Here we investigated if the neocortical aberrations of the wobbler mouse also occur in the hippocampus. Consequently, we performed extracellular field excitatory postsynaptic potential recordings in the CA1 region of the hippocampus on acute brain slices from symptomatic (P45-P60) and presymptomatic (P17-P21) wobbler mice. Significant increased excitation of hippocampal synapses was revealed by leftward shifted input/output-curves in both symptomatic and presymptomatic wobbler mice, and substantiated by population spike occurrence analyses, demonstrating that the increased synaptic excitation precedes the onset of visible phenotypic symptoms in the mouse. Synaptic facilitation tested by paired-pulse facilitation and trains in wobbler and control mice showed no differences, suggesting the absence of presynaptic defects. Immunohistochemical staining revealed that symptomatic wobbler mice have a lower number of parvalbumin positive interneurons when compared to controls and presymptomatic mice. This study reveals that the wobbler mouse model of ALS exhibits hippocampal hyperexcitability. We suggest that the hyperexcitability could be caused by increased excitatory synaptic transmission and a concomitant reduced inhibition due to a decreased number of parvalbumin positive interneurons. Thus we substantiate that wobbler brain impairments are not confined to the motor cortex, but extend to the hippocampus. Importantly, we have revealed more details of the early pathophysiology in asymptomatic animals, and studies like the present may facilitate the development of novel treatment strategies for earlier intervention in ALS patients in the future.
doi:10.1371/journal.pone.0082767
PMCID: PMC3859636  PMID: 24349357
9.  Atomic-level simulation of current–voltage relationships in single-file ion channels 
The Journal of General Physiology  2013;141(5):619-632.
The difficulty in characterizing ion conduction through membrane channels at the level of individual permeation events has made it challenging to elucidate the mechanistic principles underpinning this fundamental physiological process. Using long, all-atom simulations enabled by special-purpose hardware, we studied K+ permeation across the KV1.2/2.1 voltage-gated potassium channel. At experimentally accessible voltages, which include the physiological range, the simulated permeation rate was substantially lower than the experimentally observed rate. The current–voltage relationship was also nonlinear but became linear at much higher voltages. We observed permeation consistent with a “knock-on” mechanism at all voltages. At high voltages, the permeation rate was in accordance with our previously reported KV1.2 pore-only simulations, after the simulated voltages from the previous study were recalculated using the correct method, new insight into which is provided here. Including the voltage-sensing domains in the simulated channel brought the linear current–voltage regime closer to the experimentally accessible voltages. The simulated permeation rate, however, still underestimated the experimental rate, because formation of the knock-on intermediate occurred too infrequently. Reducing the interaction strength between the ion and the selectivity filter did not increase conductance. In complementary simulations of gramicidin A, similar changes in interaction strength did increase the observed permeation rate. Permeation nevertheless remained substantially below the experimental value, largely because of infrequent ion recruitment into the pore lumen. Despite the need to apply large voltages to simulate the permeation process, the apparent voltage insensitivity of the permeation mechanism suggests that the direct simulation of permeation at the single-ion level can provide fundamental physiological insight into ion channel function. Notably, our simulations suggest that the knock-on permeation mechanisms in KV1.2 and KcsA may be different.
doi:10.1085/jgp.201210820
PMCID: PMC3639580  PMID: 23589581
10.  Data quality in the Danish National Acute Leukemia Registry: a hematological data resource 
Clinical Epidemiology  2013;5:335-344.
Background
The Danish National Acute Leukemia Registry (DNLR) has documented coverage of above 98.5%. Less is known about the quality of the recorded data.
Objective
To describe the present coverage of the DNLR, its completeness, and accuracy of individual variables for acute myeloid leukemia (AML). Furthermore, as a second measure of true coverage of the DNLR, to estimate AML incidence in Denmark from DNLR data and compare it to incidence reported from other AML registries.
Patients and methods
By the end of December 2011, the DNLR (established January 2000) included detailed data on a large, well-defined, and nonselected Danish population of 2,665 AML patients. We estimated positive predictive values (PPVs) and completeness for 30 variables, which included patient and disease characteristics, treatment, and treatment outcomes. We identified 260 AML patients (10% of all AML patients recorded in the DNLR). We used information from medical records as the gold standard.
Results
Using the Danish National Registry of Patients as a reference, the coverage of the DNLR was 99.6%. The PPVs of the individual variables ranged from 89.4% to 100%. The completeness of individual variables varied between 60.7% and 100%. Stratification by time of registration in the DNLR (before 2006 versus 2006 and later) revealed higher PPVs and lower frequencies of missing data from 2006. Sex-adjusted incidence rates were 6.2/100,000 person-years (95% confidence interval 5.8–6.6) in males and 4.9/100,000 person-years (95% confidence interval 4.5–5.4) in females. Yearly incidence rates of AML were higher than the incidence rates reported from Sweden (4.5 and 4.2/100,000) and the US (4.5 and 3.1/100,000 in Caucasians).
Conclusion
With few exceptions, there were high values for PPVs and completeness of recorded data. Data accuracy and completeness have improved since the registry was established. The estimated incidence may indicate that the DNLR truly is more complete than other registries. In conclusion, the DNLR is a valuable resource for clinical research of AML.
doi:10.2147/CLEP.S48411
PMCID: PMC3770716  PMID: 24039451
acute myeloid leukemia; incidence; registration completeness; validation studies
12.  Ensiling of wheat straw decreases the required temperature in hydrothermal pretreatment 
Background
Ensiling is a well-known method for preserving green biomasses through anaerobic production of organic acids by lactic acid bacteria. In this study, wheat straw is subjected to ensiling in combination with hydrothermal treatment as a combined pretreatment method, taking advantage of the produced organic acids.
Results
Ensiling for 4 weeks was accomplished in a vacuum bag system after addition of an inoculum of Lactobacillus buchneri and 7% w/w xylose to wheat straw biomass at 35% final dry matter. Both glucan and xylan were preserved, and the DM loss after ensiling was less than 0.5%. When comparing hydrothermally treated wheat straw (170, 180 and 190°C) with hydrothermally treated ensiled wheat straw (same temperatures), several positive effects of ensiling were revealed. Glucan was up-concentrated in the solid fraction and the solubilisation of hemicellulose was significantly increased.
Subsequent enzymatic hydrolysis of the solid fractions showed that ensiling significantly improved the effect of pretreatment, especially at the lower temperatures of 170 and 180°C.
The overall glucose yields after pretreatments of ensiled wheat straw were higher than for non-ensiled wheat straw hydrothermally treated at 190°C, namely 74-81% of the theoretical maximum glucose in the raw material, which was ~1.8 times better than the corresponding yields for the non-ensiled straw pretreated at 170 or 180°C. The highest overall conversion of combined glucose and xylose was achieved for ensiled wheat straw hydrothermally treated at 180°C, with overall glucose yield of 78% and overall conversion yield of xylose of 87%.
Conclusions
Ensiling of wheat straw is shown to be an effective pre-step to hydrothermal treatment, and can give rise to a welcomed decrease of process temperature in hydrothermal treatments, thereby potentially having a positive effect on large scale pretreatment costs.
doi:10.1186/1754-6834-6-116
PMCID: PMC3751596  PMID: 23945109
Silage; Ensiling; Combined pretreatment; Hydrothermal treatment; Wheat straw; Enzymatic hydrolysis
13.  Mitochondrial Haplogroups Modify the Risk of Developing Hypertrophic Cardiomyopathy in a Danish Population 
PLoS ONE  2013;8(8):e71904.
Hypertrophic cardiomyopathy (HCM) is a genetic disorder caused by mutations in genes coding for proteins involved in sarcomere function. The disease is associated with mitochondrial dysfunction. Evolutionarily developed variation in mitochondrial DNA (mtDNA), defining mtDNA haplogroups and haplogroup clusters, is associated with functional differences in mitochondrial function and susceptibility to various diseases, including ischemic cardiomyopathy. We hypothesized that mtDNA haplogroups, in particular H, J and K, might modify disease susceptibility to HCM. Mitochondrial DNA, isolated from blood, was sequenced and haplogroups identified in 91 probands with HCM. The association with HCM was ascertained using two Danish control populations. Haplogroup H was more prevalent in HCM patients, 60% versus 46% (p = 0.006) and 41% (p = 0.003), in the two control populations. Haplogroup J was less prevalent, 3% vs. 12.4% (p = 0.017) and 9.1%, (p = 0.06). Likewise, the UK haplogroup cluster was less prevalent in HCM, 11% vs. 22.1% (p = 0.02) and 22.8% (p = 0.04). These results indicate that haplogroup H constitutes a susceptibility factor and that haplogroup J and haplogroup cluster UK are protective factors in the development of HCM. Thus, constitutive differences in mitochondrial function may influence the occurrence and clinical presentation of HCM. This could explain some of the phenotypic variability in HCM. The fact that haplogroup H and J are also modifying factors in ischemic cardiomyopathy suggests that mtDNA haplotypes may be of significance in determining whether a physiological hypertrophy develops into myopathy. mtDNA haplotypes may have the potential of becoming significant biomarkers in cardiomyopathy.
doi:10.1371/journal.pone.0071904
PMCID: PMC3734310  PMID: 23940792
14.  MT-CYB mutations in hypertrophic cardiomyopathy 
Mitochondrial dysfunction is a characteristic of heart failure. Mutations in mitochondrial DNA, particularly in MT-CYB coding for cytochrome B in complex III (CIII), have been associated with isolated hypertrophic cardiomyopathy (HCM). We hypothesized that MT-CYB mutations might play an important causal or modifying role in HCM. The MT-CYB gene was sequenced from DNA isolated from blood from 91 Danish HCM probands. Nonsynonymous variants were analyzed by bioinformatics, molecular modeling and simulation. Two germline-inherited, putative disease-causing, nonsynonymous variants: m.15024G>A; p.C93Y and m.15482T>C; p.S246P were identified. Modeling showed that the p.C93Y mutation leads to disruption of the tertiary structure of Cytb by helix displacement, interfering with protein–heme interaction. The p.S246P mutation induces a diproline structure, which alters local secondary structure and induces a kink in the protein backbone, interfering with macromolecular interactions. These molecular effects are compatible with a leaky phenotype, that is, limited but progressive mitochondrial dysfunction. In conclusion, we find that rare, putative leaky mtDNA variants in MT-CYB can be identified in a cohort of HCM patients. We propose that further patients with HCM should be examined for mutations in MT-CYB in order to clarify the role of these variants.
doi:10.1002/mgg3.5
PMCID: PMC3893158  PMID: 24498601
Cardiomyopathy; DNA sequencing; genetic disorders; hypertrophy; mitochondria
15.  PICK1 Deficiency Impairs Secretory Vesicle Biogenesis and Leads to Growth Retardation and Decreased Glucose Tolerance 
PLoS Biology  2013;11(4):e1001542.
Two lipid membrane sculpting BAR domain proteins, PICK1 and ICA69, play a key role early in the biogenesis of peptide hormone secretory vesicles and are critical for normal growth and metabolic homeostasis.
Secretory vesicles in endocrine cells store hormones such as growth hormone (GH) and insulin before their release into the bloodstream. The molecular mechanisms governing budding of immature secretory vesicles from the trans-Golgi network (TGN) and their subsequent maturation remain unclear. Here, we identify the lipid binding BAR (Bin/amphiphysin/Rvs) domain protein PICK1 (protein interacting with C kinase 1) as a key component early in the biogenesis of secretory vesicles in GH-producing cells. Both PICK1-deficient Drosophila and mice displayed somatic growth retardation. Growth retardation was rescued in flies by reintroducing PICK1 in neurosecretory cells producing somatotropic peptides. PICK1-deficient mice were characterized by decreased body weight and length, increased fat accumulation, impaired GH secretion, and decreased storage of GH in the pituitary. Decreased GH storage was supported by electron microscopy showing prominent reduction in secretory vesicle number. Evidence was also obtained for impaired insulin secretion associated with decreased glucose tolerance. PICK1 localized in cells to immature secretory vesicles, and the PICK1 BAR domain was shown by live imaging to associate with vesicles budding from the TGN and to possess membrane-sculpting properties in vitro. In mouse pituitary, PICK1 co-localized with the BAR domain protein ICA69, and PICK1 deficiency abolished ICA69 protein expression. In the Drosophila brain, PICK1 and ICA69 co-immunoprecipitated and showed mutually dependent expression. Finally, both in a Drosophila model of type 2 diabetes and in high-fat-diet-induced obese mice, we observed up-regulation of PICK1 mRNA expression. Our findings suggest that PICK1, together with ICA69, is critical during budding of immature secretory vesicles from the TGN and thus for vesicular storage of GH and possibly other hormones. The data link two BAR domain proteins to membrane remodeling processes in the secretory pathway of peptidergic endocrine cells and support an important role of PICK1/ICA69 in maintenance of metabolic homeostasis.
Author Summary
Regulated secretion of peptide hormones, such as growth hormone (GH) and insulin, represents a fundamental process in controlling physiological homeostasis. In endocrine cells, hormone-containing vesicles bud from the Golgi apparatus to enable storage and regulated release into the blood stream. Here we show that two proteins with a lipid membrane-shaping BAR domain, PICK1 and ICA69, work together in the pituitary gland and the pancreas to facilitate the budding of early secretory vesicle from the Golgi apparatus. The physiological significance of our findings was borne out by showing that mice and Drosophila flies lacking the PICK1 encoding gene have marked growth retardation. PICK1-deficient mice showed increased fat accumulation, reduced body weight and length, as well as reduced glucose clearance from the blood stream. Consistent with these findings, we observed a severe reduction in GH storage in the pituitary and impaired secretion of both insulin and GH in response to physiological stimuli. Finally, we found that PICK1 expression levels were raised in a fly model of type 2 diabetes and in high-fat-diet-induced obese mice. These results indicate that alteration of PICK1 expression might play a role in pathophysiological processes of metabolic diseases and/or in a protective compensatory mechanism.
doi:10.1371/journal.pbio.1001542
PMCID: PMC3635866  PMID: 23630454
16.  The roles of STP and LTP in synaptic encoding 
PeerJ  2013;1:e3.
Long-term potentiation (LTP), a cellular model of learning and memory, is generally regarded as a unitary phenomenon that alters the strength of synaptic transmission by increasing the postsynaptic response to the release of a quantum of neurotransmitter. LTP, at CA3-CA1 synapses in the hippocampus, contains a stimulation-labile phase of short-term potentiation (STP, or transient LTP, t-LTP) that decays into stable LTP. By studying the responses of populations of neurons to brief bursts of high-frequency afferent stimulation before and after the induction of LTP, we found that synaptic responses during bursts are potentiated equally during LTP but not during STP. We show that STP modulates the frequency response of synaptic transmission whereas LTP preserves the fidelity. Thus, STP and LTP have different functional consequences for the transfer of synaptic information.
doi:10.7717/peerj.3
PMCID: PMC3629019  PMID: 23638365
Short-term potentiation; Long-term potentiation; Synaptic transmission; Hippocampal slices; CA1; Schaffer collaterals; Synaptic encoding and decoding; Learning and memory
17.  Consequences of mitral valve prolapse on chordal tension: Ex vivo and in vivo studies in large animal models 
doi:10.1016/j.jtcvs.2011.08.035
PMCID: PMC3220755  PMID: 21955468
Mitral valve prolapse; animal study; biomechanics; chordal tension
18.  Saddle-shaped mitral valve annuloplasty rings improve leaflet coaptation geometry 
Objectives
The mitral valve annulus naturally conforms to a saddle shape in systole. This configuration is believed to put the leaflets into a lower-energy equilibrium with the annulus and subvalvular apparatus. Conventional flat annuloplasty rings restrict posterior leaflet motion, which may result in a “monocusp” valve, affecting valvular stress distribution. It is hypothesized that saddle-shaped annuloplasty rings cause less distortion of the physiologic leaflet geometry than do flat rings.
Methods
Twelve pigs were studied in an acute setting with 3-dimensional echocardiography and sonomicrometry before and after implantation of rigid flat (n = 5) and saddle-shaped (n = 7) annuloplasty rings. The rings were true sized to the annulus with equal anterior–posterior and commissure–commissure circumferential dimensions. The saddle-shaped rings had an annular height to commissural width ratio of 15%.
Results
Saddle-shaped rings maintained both leaflets operational (P <.01). Flat rings made the posterior leaflet immobile and the anterior leaflet aligned flat along the annulus in systole, effectively resulting in monoleaflet function. The average distance from the papillary muscle tips to the posterior annulus decreased by 2.4 ± 0.4 mm after flat ring implantation (P <.01).
Conclusions
Saddle-shaped annuloplasty rings provide better leaflet coaptation geometry than do flat rings by not hoisting the papillary muscles toward the posterior annulus through the commissural chordae, allowing greater leaflet mobility. This entails a potentially beneficial impact on valvular stress distribution that could affect durability of the repaired valve.
doi:10.1016/j.jtcvs.2011.01.022
PMCID: PMC3224846  PMID: 21329946
19.  Phthalates and Perfluorooctanesulfonic Acid in Human Amniotic Fluid: Temporal Trends and Timing of Amniocentesis in Pregnancy 
Environmental Health Perspectives  2012;120(6):897-903.
Background: Measures of prenatal environmental exposures are important, and amniotic fluid levels may directly reflect fetal exposures during hypothesized windows of vulnerability.
Objectives: We aimed to detect various phthalate metabolites and perfluorooctanesulfonic acid (PFOS) in human amniotic fluid, to study temporal exposure trends, and to estimate potential associations with gestational week of amniocentesis and maternal age and parity at amniocentesis.
Methods: We studied 300 randomly selected second-trimester amniotic fluid samples from a Danish pregnancy-screening biobank covering 1980 through 1996. We used only samples from male offspring pregnancies. We assayed the environmental pollutants by liquid chromatography/triple quadrupole mass spectrometry and analyzed data using generalized linear regression models.
Results: We detected the di(2-ethylhexyl) phthalate (DEHP) metabolite mono(2-ethyl-5-carboxypentyl) phthalate (5cx-MEPP) at a median concentration of 0.27 ng/mL [interquartile range (IQR): 0.20–0.37 ng/mL], the diisononyl phthalate (DiNP) metabolite mono(4-methyl-7-carboxyheptyl) phthalate (7cx-MMeHP) at 0.07 ng/mL (IQR: 0.05–0.11 ng/mL), and PFOS at 1.1 ng/mL (IQR: 0.66–1.60 ng/mL). An increase of 1 calendar year was associated with 3.5% lower [95% confidence interval (CI): –4.8%, –2.1%] 5cx-MEPP levels and with 7.1% higher (95% CI: 5.3%, 9.0%) 7cx-MMeHP levels. For each later gestational week of amniocentesis, 5cx-MEPP was 9.9% higher (95% CI: 4.8%, 15.2%), 7cx-MMeHP was 8.6% higher (95: CI: 2.7%, 14.9%), and PFOS was 9.4% higher (95: CI: 3.3%, 15.9%). We observed no associations with maternal age or parity.
Conclusions: Measured metabolite levels appeared to parallel decreasing DEHP exposure and increasing DiNP exposure during the study period. The environmental pollutant levels were positively associated with later gestational age at amniocentesis during pregnancy weeks 12–22.
doi:10.1289/ehp.1104522
PMCID: PMC3385442  PMID: 22398305
amniocentesis; amniotic fluid; biobank; biomonitoring; perfluorinated compounds; phthalates; pregnancy; temporal trend
20.  Flaxseed dietary fibers lower cholesterol and increase fecal fat excretion, but magnitude of effect depend on food type 
Background
Dietary fibers have been proposed to play a role in cardiovascular risk as well as body weight management. Flaxseeds are a good source of dietary fibers, and a large proportion of these are water-soluble viscous fibers.
Method
Here, we examine the effect of flaxseed dietary fibers in different food matrices on blood lipids and fecal excretion of fat and energy in a double-blind randomized crossover study with 17 subjects. Three different 7-d diets were tested: a low-fiber control diet (Control), a diet with flaxseed fiber drink (3/day) (Flax drink), and a diet with flaxseed fiber bread (3/day) (Flax bread). Total fat and energy excretion was measured in feces, blood samples were collected before and after each period, and appetite sensation registered 3 times daily before main meals.
Results
Compared to control, Flax drink lowered fasting total-cholesterol and LDL-cholesterol by 12 and 15%, respectively, (p < 0.01), whereas Flax bread only produced a reduction of 7 and 9%, respectively (p < 0.05). Fecal fat and energy excretion increased by 50 and 23% with Flax drink consumption compared to control (p < 0.05), but only fecal fat excretion was increased with Flax bread compared to control (p < 0.05).
Conclusion
Both Flax drink and Flax bread resulted in decreased plasma total and LDL-cholesterol and increased fat excretion, but the food matrix and/or processing may be of importance. Viscous flaxseed dietary fibers may be a useful tool for lowering blood cholesterol and potentially play a role in energy balance.
Trial Registration
ClinicalTrials.gov: NCT00953004
doi:10.1186/1743-7075-9-8
PMCID: PMC3307491  PMID: 22305169
Flaxseed; dietary fiber; fat excretion; cholesterol
21.  The risk of cryptorchidism among sons of women working in horticulture in Denmark: a cohort study 
Environmental Health  2011;10:100.
Background
Androgens are crucial for normal testicular descent. Studies show that some pesticides have estrogenic or antiandrogenic effects, and that female workers exposed to pesticides have increased risk of having a boy with cryptorchidism. The main objective of the present study was to investigate whether pregnant women exposed to pesticides due to their work in horticulture experience excess risk of having sons with cryptorchidism.
Methods
We conducted a cohort study of pregnant women working in horticulture using four cohorts including one cohort established with data from the departments of occupational medicine in Jutland and Funen and three existing mother-child cohorts (n = 1,468). A reference group was established from the entire Danish population of boys born in the period of 1986-2007 (n = 783,817). Nationwide Danish health registers provided information on birth outcome, cryptorchidism diagnosis and orchiopexy. The level of occupational exposure to pesticides was assessed by expert judgment blinded towards outcome status. Risk of cryptorchidism among exposed horticulture workers compared to the background population and to unexposed horticulture workers was assessed by Cox regression models.
Results
Pesticide exposed women employed in horticulture had a hazard ratio (HR) of having cryptorchid sons of 1.39 (95% CI 0.84; 2.31) and a HR of orchiopexy of 1.34 (0.72; 2.49) compared to the background population. Analysis divided into separate cohorts revealed a significantly increased risk of cryptorchidism in cohort 2: HR 2.58 (1.07;6.20) and increased risk of orchiopexy in cohort 4: HR 2.76 (1.03;7.35), but no significant associations in the other cohorts. Compared to unexposed women working in horticulture, pesticide exposed women had a risk of having sons with cryptorchidism of 1.34 (0.30; 5.96) and of orchiopexy of 1.93 (0.24;15.4).
Conclusions
The data are compatible with a slightly increased risk of cryptorchidism in sons of women exposed to pesticides by working in horticulture.
doi:10.1186/1476-069X-10-100
PMCID: PMC3250937  PMID: 22082298
Gardener; greenhouse; male genital malformation; occupational hazard; pesticide; reproduction
22.  The KCNE genes in hypertrophic cardiomyopathy: a candidate gene study 
Background
The gene family KCNE1-5, which encode modulating β-subunits of several repolarising K+-ion channels, has been associated with genetic cardiac diseases such as long QT syndrome, atrial fibrillation and Brugada syndrome. The minK peptide, encoded by KCNE1, is attached to the Z-disc of the sarcomere as well as the T-tubules of the sarcolemma. It has been suggested that minK forms part of an "electro-mechanical feed-back" which links cardiomyocyte stretching to changes in ion channel function. We examined whether mutations in KCNE genes were associated with hypertrophic cardiomyopathy (HCM), a genetic disease associated with an improper hypertrophic response.
Results
The coding regions of KCNE1, KCNE2, KCNE3, KCNE4, and KCNE5 were examined, by direct DNA sequencing, in a cohort of 93 unrelated HCM probands and 188 blood donor controls.
Fifteen genetic variants, four previously unknown, were identified in the HCM probands. Eight variants were non-synonymous and one was located in the 3'UTR-region of KCNE4. No disease-causing mutations were found and no significant difference in the frequency of genetic variants was found between HCM probands and controls. Two variants of likely functional significance were found in controls only.
Conclusions
Mutations in KCNE genes are not a common cause of HCM and polymorphisms in these genes do not seem to be associated with a propensity to develop arrhythmia
doi:10.1186/1477-5751-10-12
PMCID: PMC3204304  PMID: 21967835
23.  A Conserved PHD Finger Protein and Endogenous RNAi Modulate Insulin Signaling in Caenorhabditis elegans 
PLoS Genetics  2011;7(9):e1002299.
Insulin signaling has a profound effect on longevity and the oxidative stress resistance of animals. Inhibition of insulin signaling results in the activation of DAF-16/FOXO and SKN-1/Nrf transcription factors and increased animal fitness. By studying the biological functions of the endogenous RNA interference factor RDE-4 and conserved PHD zinc finger protein ZFP-1 (AF10), which regulate overlapping sets of genes in Caenorhabditis elegans, we identified an important role for these factors in the negative modulation of transcription of the insulin/PI3 signaling-dependent kinase PDK-1. Consistently, increased expression of pdk-1 in zfp-1 and rde-4 mutants contributed to their reduced lifespan and sensitivity to oxidative stress and pathogens due to the reduction in the expression of DAF-16 and SKN-1 targets. We found that the function of ZFP-1 in modulating pdk-1 transcription was important for the extended lifespan of the age-1(hx546) reduction-of-function PI3 kinase mutant, since the lifespan of the age-1; zfp-1 double mutant strain was significantly shorter compared to age-1(hx546). We further demonstrate that overexpression of ZFP-1 caused an increased resistance to oxidative stress in a DAF-16–dependent manner. Our findings suggest that epigenetic regulation of key upstream signaling components in signal transduction pathways through chromatin and RNAi may have a large impact on the outcome of signaling and expression of numerous downstream genes.
Author Summary
Reduced activity of the insulin-signaling pathway genes has been associated with a longer lifespan and increased resistance to oxidative stress in animals due to the activation of important transcription factors, which act as master regulators and affect large networks of genes. The ability to manipulate insulin signaling and reduce its activity may allow activation of oxidative-stress response programs in pathological conditions, such as neuronal degeneration, where oxidative stress plays a significant role. Here, we describe a new way of inhibiting insulin signaling that exists in the nematode Caenorhabditis elegans. We find that transcription of one of the insulin-signaling genes is inhibited by mechanisms involving chromatin and RNA interference, a silencing process that depends on short RNAs. We demonstrate that mutants deficient in RNA interference are more susceptible to stress due to increased insulin signaling and that increased dosage of a chromatin-binding protein repressing insulin signaling and promoting RNA interference leads to better survival of nematodes grown under oxidative stress conditions. Since there is a clear homolog of this chromatin-binding protein in mammals, it may also act to promote resistance to oxidative stress in human cells such as neurons.
doi:10.1371/journal.pgen.1002299
PMCID: PMC3183084  PMID: 21980302
24.  Integrative Analysis of the Caenorhabditis elegans Genome by the modENCODE Project 
Gerstein, Mark B. | Lu, Zhi John | Van Nostrand, Eric L. | Cheng, Chao | Arshinoff, Bradley I. | Liu, Tao | Yip, Kevin Y. | Robilotto, Rebecca | Rechtsteiner, Andreas | Ikegami, Kohta | Alves, Pedro | Chateigner, Aurelien | Perry, Marc | Morris, Mitzi | Auerbach, Raymond K. | Feng, Xin | Leng, Jing | Vielle, Anne | Niu, Wei | Rhrissorrakrai, Kahn | Agarwal, Ashish | Alexander, Roger P. | Barber, Galt | Brdlik, Cathleen M. | Brennan, Jennifer | Brouillet, Jeremy Jean | Carr, Adrian | Cheung, Ming-Sin | Clawson, Hiram | Contrino, Sergio | Dannenberg, Luke O. | Dernburg, Abby F. | Desai, Arshad | Dick, Lindsay | Dosé, Andréa C. | Du, Jiang | Egelhofer, Thea | Ercan, Sevinc | Euskirchen, Ghia | Ewing, Brent | Feingold, Elise A. | Gassmann, Reto | Good, Peter J. | Green, Phil | Gullier, Francois | Gutwein, Michelle | Guyer, Mark S. | Habegger, Lukas | Han, Ting | Henikoff, Jorja G. | Henz, Stefan R. | Hinrichs, Angie | Holster, Heather | Hyman, Tony | Iniguez, A. Leo | Janette, Judith | Jensen, Morten | Kato, Masaomi | Kent, W. James | Kephart, Ellen | Khivansara, Vishal | Khurana, Ekta | Kim, John K. | Kolasinska-Zwierz, Paulina | Lai, Eric C. | Latorre, Isabel | Leahey, Amber | Lewis, Suzanna | Lloyd, Paul | Lochovsky, Lucas | Lowdon, Rebecca F. | Lubling, Yaniv | Lyne, Rachel | MacCoss, Michael | Mackowiak, Sebastian D. | Mangone, Marco | McKay, Sheldon | Mecenas, Desirea | Merrihew, Gennifer | Miller, David M. | Muroyama, Andrew | Murray, John I. | Ooi, Siew-Loon | Pham, Hoang | Phippen, Taryn | Preston, Elicia A. | Rajewsky, Nikolaus | Rätsch, Gunnar | Rosenbaum, Heidi | Rozowsky, Joel | Rutherford, Kim | Ruzanov, Peter | Sarov, Mihail | Sasidharan, Rajkumar | Sboner, Andrea | Scheid, Paul | Segal, Eran | Shin, Hyunjin | Shou, Chong | Slack, Frank J. | Slightam, Cindie | Smith, Richard | Spencer, William C. | Stinson, E. O. | Taing, Scott | Takasaki, Teruaki | Vafeados, Dionne | Voronina, Ksenia | Wang, Guilin | Washington, Nicole L. | Whittle, Christina M. | Wu, Beijing | Yan, Koon-Kiu | Zeller, Georg | Zha, Zheng | Zhong, Mei | Zhou, Xingliang | Ahringer, Julie | Strome, Susan | Gunsalus, Kristin C. | Micklem, Gos | Liu, X. Shirley | Reinke, Valerie | Kim, Stuart K. | Hillier, LaDeana W. | Henikoff, Steven | Piano, Fabio | Snyder, Michael | Stein, Lincoln | Lieb, Jason D. | Waterston, Robert H.
Science (New York, N.Y.)  2010;330(6012):1775-1787.
We systematically generated large-scale data sets to improve genome annotation for the nematode Caenorhabditis elegans, a key model organism. These data sets include transcriptome profiling across a developmental time course, genome-wide identification of transcription factor–binding sites, and maps of chromatin organization. From this, we created more complete and accurate gene models, including alternative splice forms and candidate noncoding RNAs. We constructed hierarchical networks of transcription factor–binding and microRNA interactions and discovered chromosomal locations bound by an unusually large number of transcription factors. Different patterns of chromatin composition and histone modification were revealed between chromosome arms and centers, with similarly prominent differences between autosomes and the X chromosome. Integrating data types, we built statistical models relating chromatin, transcription factor binding, and gene expression. Overall, our analyses ascribed putative functions to most of the conserved genome.
doi:10.1126/science.1196914
PMCID: PMC3142569  PMID: 21177976
25.  Parental occupational exposure to endocrine disrupting chemicals and male genital malformations: A study in the danish national birth cohort study 
Environmental Health  2011;10:3.
Background
Sex hormones closely regulate development of the male genital organs during fetal life. The hypothesis that xenobiotics may disrupt endogenous hormonal signalling has received considerable scientific attention, but human evidence is scarce.
Objectives
We analyse occurrence of hypospadias and cryptorchidism according to maternal and paternal occupational exposure to possible endocrine disrupting chemicals.
Methods
We conducted a follow-up study of 45,341 male singleton deliveries in the Danish National Birth Cohort during 1997-2009. Information on work during pregnancy was obtained by telephone interviews around gestational week 16. Parents' job titles were classified according to DISCO-88. A job exposure matrix for endocrine disrupting chemicals (EDCs) was implemented to assess occupational exposures. The Medical Birth and National Hospital Register provided data on congenital anomalies diagnosed at birth or during follow-up, which ended in 2009. Crude and adjusted hazard ratios (HR) were obtained from Cox regression models.
Results
Among all pregnancies, 6.3% were classified as possibly or probably exposed to EDCs. The most prevalent occupations conferring possible exposure were cleaners, laboratory technicians, hairdressers and agricultural workers (58% of all potentially exposed). The final cumulative incidence of cryptorchidism in boys was 2.2% (1002 cases), and of hypospadias 0.6% (262 cases). The occurrence of hypospadias increased when mothers were probably [HRa = 1.8 (95% CI 1.0-2.6)] or possibly exposed to one or more EDCs [HRa = 2.6 (95% CI 1.8-3.4). Possible paternal exposure to heavy metals increased the risk of hypospadias [HRa 2.2 (95% CI: 1.0-3.4)] and cryptorchidism [HRa 1.9 (95% CI: 1.1-2.7)]. None of the exposure groups reached statistical significance.
Conclusion
The study provides some but limited evidence that occupational exposure to possible endocrine disrupting chemicals during pregnancy increases the risk of hypospadias.
doi:10.1186/1476-069X-10-3
PMCID: PMC3033238  PMID: 21235764

Results 1-25 (30)