Håvard Jenssen

• Nainamalai, Varatharajan; Jenssen, Håvard; Rezaeitaleshmahalleh, Mostafa; Prophete, Djinaud; Gosnell, Jordan & Khan, Sarah [Vis alle 9 forfattere av denne artikkelen] (2025). A longitudinal analysis of morphological shape variation of spleen in patients with fontan surgery. Informatics in Medicine Unlocked (IMU). 57. doi: 10.1016/j.imu.2025.101665. Fulltekst i vitenarkiv
• Nainamalai, Varatharajan; Jenssen, Håvard; Boretto, Luca; Luthra, Nikhil André Kumar; Espinoza, Andreas & Pelanis, Egidijus [Vis alle 11 forfattere av denne artikkelen] (2025). Morphological changes on the human liver during minimally invasive surgery: Implications for image-guided interventions and surgical navigation. Surgical Endoscopy. ISSN 0930-2794. doi: 10.1007/s00464-025-12392-y. Fulltekst i vitenarkiv
• Jenssen, Håvard; Nainamalai, Varatharajan; Pelanis, Egidijus; Kumar, Rahul Prasanna; Abildgaard, Andreas & Kolrud, Finn Kristian [Vis alle 11 forfattere av denne artikkelen] (2025). Challenges and artificial intelligence solutions for clinically optimal hepatic venous vessel segmentation. Biomedical Signal Processing and Control. ISSN 1746-8094. 106. doi: 10.1016/j.bspc.2025.107822. Fulltekst i vitenarkiv Vis sammendrag

  Background : Liver vessel identification is crucial for clinical disease assessment and treatment planning, especially concerning local treatment of liver tumors. As artificial intelligence (AI) develops in radiology, opportunities arise to craft models adept at hepatic venous vessel segmentation, opening possibilities for creating patient-specific models of the liver anatomy quickly, despite the diverse features of CT images encountered in clinical settings. Objective: This research evaluates the performance of AI models combined with various pre-processing filters for liver vessel segmentation, emphasizing clinically relevant results. A novel evaluation method was introduced to offer more anatomically accurate assessments, moving beyond traditional metrics like the Dice score. Methods: Using open-source and proprietary datasets, we implemented residual UNet and Dense UNet in combination with smoothness and vesselness filters. We used a clinical evaluation approach focused on major and minor liver vessels, thereby underscoring the precision of AI outcomes. Results: The Dense UNet model with a specific pre-processing filter produced an average Dice score of 0.8144 in our internal dataset. For the public test dataset, the score was 0.7859. Both scores were higher than those not using pre-processing filters, 0.8052 and 0.7765. Clinical assessments showed 85% of AI predictions accurately identified all wanted vessel structures, though segmentation beyond the vessel borders did occur in half the predictions. Conclusion: This study highlights the effectiveness of AI in liver vessel segmentation, with the Dense UNet model combined with pre-processing filters showing high Dice scores and clinical accuracy.

• Mishra, Shyam Kumar; Yasir, Muhammad; Kuppusamy, Rajesh; Wong, Edgar H. H.; Hui, Alex & Sørensen, Kristian [Vis alle 10 forfattere av denne artikkelen] (2025). Antimicrobial activity of peptoids against Metallo-β-lactamase-producing Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and other WHO priority pathogens, including Candida auris. Journal of Applied Microbiology. ISSN 1364-5072. 136(3). doi: 10.1093/jambio/lxaf031. Fulltekst i vitenarkiv Vis sammendrag

  Aims The World Health Organization has identified ESKAPE bacteria and Candida auris as priority pathogens, emphasizing an urgent need for novel antimicrobials to combat them. This study aimed to explore the therapeutic potential of antimicrobial peptidomimetics, specifically peptoids with sequence-specific N-substituted glycines, against ESKAPEE pathogens, including metallo-β-lactamase (MBL) producers, as well as C. auris strains. Methods and results This study evaluated activity of the peptoids against the multidrug-resistant priority pathogens. The peptoid TM8 (with an N-decyl alkyl chain) demonstrated a geometric mean minimum inhibitory concentration (MIC) of 7.8 μg ml−1 against MBL-producing bacteria, and 5.5 μg ml−1 against C. auris. TM8 showed synergy with ciprofloxacin, enhancing its effectiveness 4-fold against NDM-1-producing Klebsiella pneumoniae. No antagonism was seen when TM8 was used with either conventional antibiotics or antifungals. Peptoids that had therapeutic indices below 3 were generally more hydrophobic, due to either alkyl chains or bromine. Scanning electron microscopy and live-dead staining assay on peptoid-treated C. auris confirmed morphological changes and killing activity, respectively. Furthermore, the peptoid could effectively inhibit biofilm formation by C. auris. Conclusion Peptoids demonstrated antibacterial activity against ESKAPEE, particularly against MBL-producing Gram-negative bacteria. Additionally, they exhibited antifungal and anti-biofilm activities against C. auris strains.

• Nainamalai, Varatharajan; Jenssen, Håvard; Suha, Khadiza Tun; Rezaeitaleshmahalleh, Mostafa; Wang, Min & Khan, Sarah [Vis alle 9 forfattere av denne artikkelen] (2024). Morphological Changes of Liver Among Post-Fontan Surgery Patients. Journal of Medical and Biological Engineering (JMBE). ISSN 1609-0985. 44(6), s. 871–882. doi: 10.1007/s40846-024-00910-7. Fulltekst i vitenarkiv
• Lone, Abdullah; Nielsen, Josefine Eilsø; Thulstrup, Peter W.; Lund, Reidar; Hansen, Paul Robert & Jenssen, Håvard (2022). Cyclic N-locked indolicidin analogues with antimicrobial activity: Effect of ring size and fatty acid acylation. European Journal of Medicinal Chemistry Reports. ISSN 2772-4174. 6. doi: 10.1016/j.ejmcr.2022.100080. Fulltekst i vitenarkiv
• Nielsen, Josefine Eilsø; Bjørnestad, Victoria Ariel; Pipich, Vitaliy; Jenssen, Håvard & Lund, Reidar (2020). Beyond structural models for the mode of action: How natural antimicrobial peptides affect lipid transport. Journal of Colloid and Interface Science. ISSN 0021-9797. 582, s. 793–802. doi: 10.1016/j.jcis.2020.08.094. Fulltekst i vitenarkiv Vis sammendrag

  Hypothesis: Most textbook models for antimicrobial peptides (AMP) mode of action are focused on structural effects and pore formation in lipid membranes, while these deformations have been shown to require high concentrations of peptide bound to the membrane. Even insertion of low amounts of peptides in the membrane is hypothesized to affect the transmembrane transport of lipids, which may play a key role in the peptide effect on membranes. Experiments: Here we combine state-of-the-art small angle X-ray/neutron scattering (SAXS/SANS) techniques to systematically study the effect of a broad selection of natural AMPs on lipid membranes. Our approach enables us to relate the structural interactions, effects on lipid exchange processes, and thermodynamic parameters, directly in the same model system. Findings: The studied peptides, indolicidin, aurein 1.2, magainin II, cecropin A and LL-37 all cause a general acceleration of essential lipid transport processes, without necessarily altering the overall structure of the lipid membranes or creating organized pore-like structures. We observe rapid scrambling of the lipid composition associated with enhanced lipid transport which may trigger lethal signaling processes and enhance ion transport. The reported membrane effects provide a plausible canonical mechanism of AMP-membrane interaction and can reconcile many of the previously observed effects of AMPs on bacterial membranes.

• Molchanova, Natalia; Nielsen, Josefine Eilsø; Sørensen, Kristian B; Krishna, Bala; Hansen, Paul Robert & Lund, Reidar [Vis alle 8 forfattere av denne artikkelen] (2020). Halogenation as a tool to tune antimicrobial activity of peptoids. Scientific Reports. 10(1). doi: 10.1038/s41598-020-71771-8. Fulltekst i vitenarkiv Vis sammendrag

  Abstract Antimicrobial peptides have attracted considerable interest as potential new class of antibiotics against multi-drug resistant bacteria. However, their therapeutic potential is limited, in part due to susceptibility towards enzymatic degradation and low bioavailability. Peptoids (oligomers of N -substituted glycines) demonstrate proteolytic stability and better bioavailability than corresponding peptides while in many cases retaining antibacterial activity. In this study, we synthesized a library of 36 peptoids containing fluorine, chlorine, bromine and iodine atoms, which vary by length and level of halogen substitution in position 4 of the phenyl rings. As we observed a clear correlation between halogenation of an inactive model peptoid and its increased antimicrobial activity, we designed chlorinated and brominated analogues of a known peptoid and its shorter counterpart. Short brominated analogues displayed up to 32-fold increase of the activity against S. aureus and 16- to 64-fold against E. coli and P. aeruginosa alongside reduced cytotoxicity. The biological effect of halogens seems to be linked to the relative hydrophobicity and self-assembly properties of the compounds. By small angle X-ray scattering (SAXS) we have demontrated how the self-assembled structures are dependent on the size of the halogen, degree of substitution and length of the peptoid, and correlated these features to their activity.

• Lone, Abdullah; Thomsen, Thomas T; Nielsen, Josefine Eilsø; Thulstrup, Peter W; Klitgaard, Rasmus N & Løbner-Olesen, Anders [Vis alle 9 forfattere av denne artikkelen] (2019). Structure-activity study of an all-D antimicrobial octapeptide D2D. Molecules. ISSN 1431-5157. 24(24). doi: 10.3390/molecules24244571. Fulltekst i vitenarkiv
• Nielsen, Josefine Eilsø; Lind, Tania Kjellerup; Lone, Abdullah; Gerelli, Yuri; Hansen, Paul Robert & Jenssen, Håvard [Vis alle 8 forfattere av denne artikkelen] (2019). A biophysical study of the interactions between the antimicrobial peptide indolicidin and lipid model systems. Biochimica et Biophysica Acta - Biomembranes. ISSN 0005-2736. 1861(7), s. 1355–1364. doi: 10.1016/j.bbamem.2019.04.003. Fulltekst i vitenarkiv Vis sammendrag

  The naturally occurring peptide indolicidin from bovine neutrophils exhibits strong biological activity against a broad spectrum of microorganisms. This is believed to arise from selective interactions with the negatively charged cytoplasmic lipid membrane found in bacteria. We have investigated the peptide interaction with supported lipid model membranes using a combination of complementary surface sensitive techniques: neutron reflectometry (NR), atomic force microscopy (AFM), and quartz crystal microbalance with dissipation monitoring (QCM-D). The data are compared with small-angle X-ray scattering (SAXS) results obtained with lipid vesicle/peptide solutions. The peptide membrane interaction is shown to be significantly concentration dependent. At low concentrations, the peptide inserts at the outer leaflet in the interface between the headgroup and tail core. Insertion of the peptide results in a slight decrease in the lipid packing order of the bilayer, although not sufficient to cause membrane thinning. By increasing the indolicidin concentration well above the physiologically relevant conditions, a deeper penetration of the peptide into the bilayer and subsequent lipid removal take place, resulting in a slight membrane thinning. The results suggest that indolicidin induces lipid removal and that mixed indolicidin-lipid patches form on top of the supported lipid bilayers. Based on the work presented using model membranes, indolicidin seems to act through the interfacial activity model rather than through the formation of stable pores.

• Jenssen, Håvard; Gutteberg, tore jarl & Lejon, Tore Sigvard (2006). MODELLING THE ANTI-HSV ACTIVITY OF SMALL, CATIONIC PEPTIDES USING AMINO ACID DESCRIPTORS. Journal of Peptide Research. ISSN 1397-002X. 66, s. 48–56. Fulltekst i vitenarkiv
• Jenssen, Håvard; Gutteberg, tore jarl; Rekdal, Øystein & Lejon, Tore Sigvard (2006). Prediction of activity, synthesis and biological testing of anti-HSV active peptides. Chemical Biology and Drug Design (CB&DD). ISSN 1747-0277. 68, s. 58–66. Fulltekst i vitenarkiv
• Jenssen, Håvard; Gutteberg, Tore Jarl & Lejon, Tore Sigvard (2005). Modelling of anti-HSV activity of lactoferricin analogues using amino acid descriptors. Journal of Peptide Science. ISSN 1075-2617. 11(2), s. 97–103. Fulltekst i vitenarkiv
• Hunter, HN; Demcoe, AR; Jenssen, Håvard; Gutteberg, Tore Jarl & Vogel, HJ (2005). Human lactoferricin is partially folded in aqueous solution and is better stabilized in a membrane mimetic solvent. Antimicrobial Agents and Chemotherapy. ISSN 0066-4804. 49(8), s. 3387–3395. Fulltekst i vitenarkiv
• Samuelsen, Ørjan; Haukland, Hanne; Jenssen, Håvard; Kramer, M; Sandvik, K & Ulvatne, Hilde [Vis alle 7 forfattere av denne artikkelen] (2005). Induced resistance to the antimicrobial peptide lactoferricin B in Staphylococcus aureus. FEBS Letters. ISSN 0014-5793. 579. Fulltekst i vitenarkiv
• Jenssen, Håvard; Andersen, Jeanette Hammer; Uhlin-Hansen, Lars; Gutteberg, Tore Jarl & Rekdal, Øystein (2004). Anti-HSV activity of lactoferricin analogues is only partly related to their affinity for heparan sulfate. Antiviral Research. ISSN 0166-3542. 61, s. 101–109. Fulltekst i vitenarkiv
• Andersen, Jeanette Hammer; Jenssen, Håvard; Sandvik, K & Gutteberg, Tore Jarl (2004). The anti-HSV activity of lactoferrin and lactoferricin is dependent on the presence of heparan sulphate at the cell surface. Journal of Medical Virology. ISSN 0146-6615. 74, s. 262–271. Fulltekst i vitenarkiv

Se alle arbeider i NVA

• Jenssen, Håvard (2025). Self-assembling peptoid-based antimicrobial nanomaterials. Nanomedicine. ISSN 1743-5889. doi: 10.1080/17435889.2025.2469482. Fulltekst i vitenarkiv
• Jenssen, Håvard; Berg, Anders & Krogh, Halldor (2007). Ekspedisjonen Tangaroa / regi: Håvard Jenssen og Anders Berg ; produsent: Håvard Jenssen ; musikk: Halldor Krogh. Fulltekst i vitenarkiv Vis sammendrag

  TV-dokumentar om seilas med balsaflåte i Thor Heyerdahls fotspor 60 år seinere.

• Røsler, Alexander; Jenssen, Håvard & Krogh, Halldor (2005). Makten og æren / manus og regi: Alexander Røsler ; foto og klipp: Håvard Jenssen ; musikk av Halldor Krogh ; kommentar lest av Nils Nordberg ; produsent Kjell Eriksen. Fulltekst i vitenarkiv Vis sammendrag

  Dokumentarfilm om general Carl Gustav Fleischer

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