Publications by authors named "Jan Jacobsen"

The ecological role of heritable phenotypic variation in free-living populations remains largely unknown. Knowledge of the genetic basis of functional ecological processes can link genomic and phenotypic diversity, providing insight into polymorphism evolution and how populations respond to environmental changes. By quantifying the marine diet of Atlantic salmon, we assessed how foraging behaviour changes along the ontogeny, and in relation to genetic variation in two loci with major effects on age at maturity (six6 and vgll3).

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The noradrenaline system attracts attention for its role in mood disorders and neurodegenerative diseases but the lack of well-validated methods impairs our understanding when assessing its function and release in vivo. This study combines simultaneous positron emission tomography (PET) and microdialysis to explore if [C]yohimbine, a selective antagonist radioligand of the α2 adrenoceptors, may be used to assess in vivo changes in synaptic noradrenaline during acute pharmacological challenges. Anesthetised Göttingen minipigs were positioned in a head holder in a PET/CT device.

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The Atlantic herring L has a vast geographical distribution and a complex population structure with a few very large migratory units and many small local populations. Each population has its own spawning ground and/or time, thereby maintaining their genetic integrity. Several herring populations migrate between common feeding grounds and over-wintering areas resulting in frequent mixing of populations.

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Introduction: The peripheral autonomic nervous system may be involved years before onset of motor symptoms in some patients with Parkinson's disease (PD). Specific imaging techniques to quantify the cholinergic nervous system in peripheral organs are an unmet need. We tested the hypothesis that patients with PD display decreased [F]FEOBV uptake in peripheral organs - a sign of parasympathetic denervation.

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Background: The autonomic nervous system is frequently affected in some neurodegenerative diseases, including Parkinson's disease and Dementia with Lewy bodies. In vivo imaging methods to visualize and quantify the peripheral cholinergic nervous system are lacking. By using [F]FEOBV PET, we here describe the peripheral distribution of the specific cholinergic marker, vesicular acetylcholine transporters (VAChT), in human subjects.

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Objective: Imaging activated glutamate N-methyl-D-aspartate receptor ion channels (NMDAR-ICs) using positron emission tomography (PET) has proved challenging due to low brain uptake, poor affinity and selectivity, and high metabolism and dissociation rates of candidate radioligands. The radioligand [ F]GE-179 is a known use-dependent marker of NMDAR-ICs. We studied whether interictal [ F]GE-179 PET would detect foci of abnormal NMDAR-IC activation in patients with refractory focal epilepsy.

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Article Synopsis
  • * Researchers injected either preformed a-syn fibrils (PFF) or soluble a-syn into rats and monitored their behavior while also using PET imaging and histological analysis to assess brain changes over time.
  • * Results showed that PFF injections led to a gradual decline in dopamine terminals and an increase in immune response in the brain, indicating that a-syn pathology develops progressively and disrupts synaptic function before significant cell death occurs.
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The positron emission tomography (PET) tracer [F]GE-179 binds to the phencyclidine (PCP) site in the open -methyl-D-aspartate receptor ion channel (NMDAR-IC). To demonstrate that PET can visualise increased [F]GE-179 uptake by active NMDAR-ICs and that this can be blocked by the PCP antagonist S-ketamine, 15 rats had an electrode unilaterally implanted in their ventral hippocampus. Seven rats had no stimulation, five received pulsed 400 µA supra-threshold 60 Hz stimulation alone, and three received intravenous S-ketamine injection prior to stimulation.

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The number of functionally active synapses provides a measure of neural integrity, with reductions observed in neurodegenerative disorders. [11C]UCB-J binds to synaptic vesicle 2A (SV2A) transmembrane protein located in secretory vesicles. We aimed to assess [11C]UCB-J PET as an in vivo biomarker of regional cerebral synaptic SV2A density in rat lesion models of neurodegeneration.

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Purpose: Loss of neuronal synapse function is associated with a number of brain disorders. The [C]UCB-J positron emission tomography (PET) tracer allows for in vivo examination of synaptic density, as it binds to synaptic vesicle glycoprotein 2A (SV2A) expressed in presynaptic terminals. Here, we characterise [C]UCB-J imaging in Göttingen minipigs.

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Background: No PET radioligand has yet demonstrated the capacity to map glutamate N-methyl-d-aspartate receptor ion channel (NMDAR-IC) function. [F]GE-179 binds to the phencyclidine (PCP) site in open NMDAR-ICs and potentially provides a use-dependent PET biomarker of these ion channels.

Objective: To show [F]GE-179 PET can detect increased NMDAR-IC activation during electrical deep brain stimulation (DBS) of pig hippocampus.

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The sex determination system of Atlantic herring Clupea harengus L., a commercially important fish, was investigated. Low coverage whole-genome sequencing of 48 females and 55 males and a genome-wide association study revealed two regions on chromosomes 8 and 21 associated with sex.

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Atlantic herring (Clupea harengus) is one of the most abundant fish species in the world. It is an important economical and nutritional resource, as well as a crucial part of the North Atlantic ecosystem. In 2016, a draft herring genome assembly was published.

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Article Synopsis
  • Piscine orthoreovirus genotype 1 (PRV-1) is commonly found in farmed Atlantic salmon in northern Europe and has been detected in wild fish in Norway and Canada, but its impact on wild populations is not well understood.
  • A survey conducted on 1,130 wild salmonids across various countries revealed the first instances of PRV-1 in wild fish from Denmark, Sweden, Faroe Islands, and Ireland, with prevalence rates varying by region.
  • The study highlights the need for monitoring PRV-1 in wild fish populations, especially broodfish for restocking programs, due to the virus's geographical spread and genetic diversity.
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γ-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the nervous system acting mainly through GABA receptors. In the presence of high levels of GABA, an allosteric shift in the GABA receptors can change the affinity of benzodiazepine (BZD) ligands. Valproic acid (VPA) is an anticonvulsant that enhances the level of endogenous GABA in the brain.

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Degeneration of noradrenergic neurons may underlie the disabling nonmotor symptoms in patients with Parkinson disease (PD). Quantification of the loss of noradrenergic neurons by means of neuroimaging has been limited by the lack of radioligands that are selective for noradrenergic neurotransmission. The radioligand ()-C-2-(α-(2-methoxyphenoxy)benzyl)morpholine (C-MeNER) is a highly selective inhibitor of noradrenaline transporters, and PET studies suggest that this radioligand is suitable for quantitative neuroimaging of noradrenergic deficits in human brain in vivo.

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Unlabelled: Increasing evidence supports a decisive role for inflammation in the neurodegenerative process of Parkinson's disease (PD). The immune response in PD seems to involve, not only microglia, but also other immune cells infiltrated into the brain. Indeed, we observed here the infiltration of macrophages, specifically CD163+ macrophages, into the area of neurodegeneration in the 6-hydroxydopamine (6-OHDA) PD model.

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Balancing trophic and apoptotic cues is critical for development and regeneration of neuronal circuits. Here we identify SorCS2 as a proneurotrophin (proNT) receptor, mediating both trophic and apoptotic signals in conjunction with p75(NTR). CNS neurons, but not glia, express SorCS2 as a single-chain protein that is essential for proBDNF-induced growth cone collapse in developing dopaminergic processes.

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The identification of the novel, selective, orally bioavailable Sortilin inhibitor AF38469 is described. Structure-activity relationships and syntheses are reported, along with an X-ray crystal structure of the sortilin-AF38469 protein-inhibitor complex.

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Objectives: To examine vascular endothelial growth factor (VEGF), VEGF-receptor-(R)1, and R2 mRNA levels in renal cell carcinoma (RCC), a tumour generally refractory to most medical therapy, but for which a potentially useful therapeutic alternative is inhibition of angiogenesis.

Patients And Methods: VEGF, VEGF-R1 and -R2 mRNA levels were analysed using the quantitative reverse transcription-polymerase chain reaction. RNA was extracted from 84 conventional (clear cell) RCCs (cRCC), 20 papillary (pRCC), six chromophobe (chRCC), and 27 corresponding kidney cortex tissues, obtained from 110 patients in whom high-quality RNA was available from the tumours (53 women and 57 men, mean age 64.

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Article Synopsis
  • - The study compared various cation-exchange resins, such as Fractogel and MacroPrep, in terms of several chromatographic factors like pH dependence, efficiency, and particle size, specifically analyzing their performance with proteins like Anti-FVII Mab, aprotinin, and lysozyme.
  • - It was found that for proteins with a pI above the experimental pH, pH had little impact on retention, whereas the Anti-FVII Mab showed binding at pH 7.5 on multiple resins, and increased flow rates led to higher plate height in efficiency measurements.
  • - The research also highlighted the significant influence of salt concentration on binding strength and revealed that competitive binding from fermentation components lowered the dynamic binding
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Objective: To investigate the protein expression of vascular endothelial growth factor (VEGF) isoforms in relation to the clinical course in patients with different renal cell carcinoma (RCC) types, as angiogenesis is essential for tumour growth and metastasis.

Patients And Methods: Western blots were assayed of protein extracts from tumour and concomitant kidney cortex samples from 96 patients. The levels of VEGF189, VEGF165, and VEGF121 isoforms were correlated with clinicopathological characteristics and survival.

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Article Synopsis
  • A comparative study examined various chromatographic resins, including heparin and cation exchangers, analyzing factors like efficiency, binding strength, and capacity.
  • The experiments involved four different proteins, showing that pH had a minimal effect on retention for proteins with high isoelectric points, but certain resins had a notable decrease in retention as pH rose.
  • Results indicated that cation-exchange resins’ binding strength varied with ionic strength and protein type, with significant dynamic capacity utilized during operations, revealing potential substitutes for heparin resins in specific conditions.*
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Obesity is associated with an increased risk of certain cancers, including renal cell carcinoma. A possible mediator of this risk is insulin-like growth factor-1 (IGF-1). The authors evaluated the prognostic information of IGF-1, IGFBP-3, leptin, and prealbumin in sera sampled at diagnosis from 256 consecutive patients with renal cell carcinoma.

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