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Gudjonsson, Olafur
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Publications (10 of 10) Show all publications
Juratli, T. A., Jones, P. S., Wang, N., Subramanian, M., Aylwin, S. J. B., Odia, Y., . . . Brastianos, P. K. (2019). Targeted treatment of papillary craniopharyngiomas harboring BRAF V600E mutations. Cancer, 125(17), 2910-2914
Open this publication in new window or tab >>Targeted treatment of papillary craniopharyngiomas harboring BRAF V600E mutations
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2019 (English)In: Cancer, ISSN 0008-543X, E-ISSN 1097-0142, Vol. 125, no 17, p. 2910-2914Article in journal, Editorial material (Other academic) Published
Abstract [en]

Papillary craniopharyngiomas (PCPs) are characterized by the presence of BRAF V600E mutations, which are emerging as a useful guide for diagnosis and treatment decision making. The ongoing multicenter phase 2 Alliance A071601 trial is evaluating the efficacy of BRAF and mitogen-activated protein kinase kinase (MEK) inhibitors for patients with PCPs. With continued successful responses, it is proposed that BRAF (and MEK) inhibitors be evaluated for the neoadjuvant treatment of patients with PCPs.

Place, publisher, year, edition, pages
WILEY, 2019
National Category
Cancer and Oncology
Identifiers
urn:nbn:se:uu:diva-396181 (URN)10.1002/cncr.32197 (DOI)000476048400001 ()31314136 (PubMedID)
Available from: 2019-10-31 Created: 2019-10-31 Last updated: 2019-10-31Bibliographically approved
Ölander, C., Gudjonsson, O., Kinnefors, A., Laurell, G. & Edfeldt, L. (2018). Complications in translabyrinthine surgery of vestibular schwannoma. Acta Oto-Laryngologica, 138(7), 639-645
Open this publication in new window or tab >>Complications in translabyrinthine surgery of vestibular schwannoma
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2018 (English)In: Acta Oto-Laryngologica, ISSN 0001-6489, E-ISSN 1651-2251, Vol. 138, no 7, p. 639-645Article in journal (Refereed) Published
Abstract [en]

Objective: To evaluate the risk of complications associated with tumor size and patient's age in translabyrinthine vestibular schwannoma surgery. Methods: 700 patients with vestibular schwannoma primarily underwent translabyrinthine surgery between 1988 and 2014. Pre- and postoperative data were collected in a database and incidence of the postoperative complications cerebrospinal fluid leakage, meningitis, intracranial hemorrhage (ICH), facial nerve function and mortality were assessed and related to the tumor size and patient's age and retrospectively evaluated. Results: The tumor size significantly influenced the incidence of ICH and facial nerve dysfunction whereas age was correlated to facial nerve outcome. Conclusions: The translabyrinthine approach is a safe surgical procedure with relatively low risks of complications. The tumor size was significantly associated with a higher risk of ICH and facial nerve dysfunction whereas age only influenced the facial nerve outcome.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
Keywords
Translabyrinthine surgery, complications, tumor size, age
National Category
Neurology Otorhinolaryngology
Identifiers
urn:nbn:se:uu:diva-356818 (URN)10.1080/00016489.2018.1427887 (DOI)000432629200008 ()29361875 (PubMedID)
Available from: 2018-08-16 Created: 2018-08-16 Last updated: 2018-08-16Bibliographically approved
Li, H., Edin, F., Hayashi, H., Gudjonsson, O., Danckwardt-Lillieström, N., Engqvist, H., . . . Xia, W. (2017). Guided Growth of Auditory Neurons: Bioactive Particles Towards Gapless Neural - Electrode Interface. Biomaterials, 122, 1-9
Open this publication in new window or tab >>Guided Growth of Auditory Neurons: Bioactive Particles Towards Gapless Neural - Electrode Interface
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2017 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 122, p. 1-9Article in journal (Refereed) Published
Abstract [en]

Cochlear implant (CI) is a successful device to restore hearing. Despite continuous development, frequency discrimination is poor in CI users due to an anatomical gap between the auditory neurons and CI electrode causing current spread and unspecific neural stimulation. One strategy to close this anatomical gap is guiding the growth of neuron dendrites closer to CI electrodes through targeted slow release of neurotrophins. Biodegradable calcium phosphate hollow nanospheres (CPHSs) were produced and their capacity for uptake and release of neurotrophins investigated using I-125-conjugated glia cell line-derived neurotrophic factor (GDNF). The CPHSs were coated onto CI electrodes and loaded with neurotrophins. Axon guidance effect of slow-released neurotrophins from the CPHSs was studied in an in vitro 3D culture model. CPHS coating bound and released GDNF with an association rate constant 6.3 x 10(3) M(-1)s(-1) and dissociation rate 2.6 x 10(-5) s(-1), respectively. Neurites from human vestibulocochlear ganglion explants found and established physical contact with the GDNF-loaded CPHS coating on the CI electrodes placed 0.7 mm away. Our results suggest that neurotrophin delivery through CPHS coating is a plausible way to close the anatomical gap between auditory neurons and electrodes. By overcoming this gap, selective neural activation and the fine hearing for CI users become possible.

National Category
Medical and Health Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-276334 (URN)10.1016/j.biomaterials.2016.12.020 (DOI)000394472500001 ()28107660 (PubMedID)
Funder
Swedish Research Council, 2013-5419
Available from: 2016-03-07 Created: 2016-02-11 Last updated: 2018-02-08Bibliographically approved
Vlachogiannis, P., Gudjonsson, O., Montelius, A., Grusell, E., Isacsson, U., Nilsson, K. & Blomquist, E. (2017). Hypofractionated high-energy proton-beam irradiation is an alternative treatment for WHO grade I meningiomas. Acta Neurochirurgica, 159(12), 2391-2400
Open this publication in new window or tab >>Hypofractionated high-energy proton-beam irradiation is an alternative treatment for WHO grade I meningiomas
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2017 (English)In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940, Vol. 159, no 12, p. 2391-2400Article in journal (Refereed) Published
Abstract [en]

Radiation treatment is commonly employed in the treatment of meningiomas. The aim of this study was to evaluate the effectiveness and safety of hypofractionated high-energy proton therapy as adjuvant or primary treatment for WHO grade I meningiomas. A total of 170 patients who received irradiation with protons for grade I meningiomas between 1994 and 2007 were included in the study. The majority of the tumours were located at the skull base (n = 155). Eighty-four patients were treated post subtotal resection, 42 at tumour relapse and 44 with upfront radiotherapy after diagnosis based on the typical radiological image. Irradiation was given in a hypofractionated fashion (3-8 fractions, usually 5 or 6 Gy) with a mean dose of 21.9 Gy (range, 14-46 Gy). All patients were planned for follow-up with clinical controls and magnetic resonance imaging scans at 6 months and 1, 2, 3, 5, 7 and 10 years after treatment. The median follow-up time was 84 months. Age, gender, tumour location, Simpson resection grade and target volume were assessed as possible prognostic factors for post-irradiation tumour progression and radiation related complications. The actuarial 5- and 10-year progression-free survival rates were 93% and 85% respectively. Overall mortality rate was 13.5%, while disease-specific mortality was 1.7% (3/170 patients). Older patients and patients with tumours located in the middle cranial fossa had a lower risk for tumour progression. Radiation-related complications were seen in 16 patients (9.4%), with pituitary insufficiency being the most common. Tumour location in the anterior cranial fossa was the only factor that significantly increased the risk of complications. Hypofractionated proton-beam radiation therapy may be used particularly in the treatment of larger World Health Organisation grade I meningiomas not amenable to total surgical resection. Treatment is associated with high rates of long-term tumour growth control and acceptable risk for complications.

Keywords
Meningioma, Benign meningioma, Proton beam irradiation, Hypofractionation
National Category
Neurology
Identifiers
urn:nbn:se:uu:diva-342199 (URN)10.1007/s00701-017-3352-4 (DOI)000415354800024 ()29064038 (PubMedID)
Available from: 2018-02-20 Created: 2018-02-20 Last updated: 2018-02-20Bibliographically approved
Rostami, E., Nyström, P. W., Libard, S., Wikström, J., Casar Borota, O. & Gudjonsson, O. (2017). Recurrent papillary craniopharyngioma with BRAFV600E mutation treated with neoadjuvant-targeted therapy.. Acta Neurochirurgica, 159(11), 2217-2221
Open this publication in new window or tab >>Recurrent papillary craniopharyngioma with BRAFV600E mutation treated with neoadjuvant-targeted therapy.
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2017 (English)In: Acta Neurochirurgica, ISSN 0001-6268, E-ISSN 0942-0940, Vol. 159, no 11, p. 2217-2221Article in journal (Refereed) Published
Abstract [en]

Craniopharyngiomas are histologically benign but locally aggressive tumors in the sellar region that may cause devastating neurological and endocrine deficits. They tend to recur following surgery with high morbidity; hence, postoperative radiotherapy is recommended following sub-total resection. BRAFV600E mutation is the principal oncogenic driver in the papillary variant of craniopharyngiomas. Recently, a dramatic tumor reduction has been reported in a patient with BRAFV600E mutated, multiply recurrent papillary craniopharyngioma using a combination therapy of BRAF inhibitor dabrafenib and MEK inhibitor trametinib. Here, we report on near-radical reduction of a growing residual BRAFV600E craniopharyngioma using the same neoadjuvant therapy.

Keywords
BRAFV600E, Craniopharyngioma, RAF-inhibitor
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-333691 (URN)10.1007/s00701-017-3311-0 (DOI)000412754600027 ()28918496 (PubMedID)
Available from: 2017-11-16 Created: 2017-11-16 Last updated: 2018-01-08Bibliographically approved
Ryttlefors, M., Danfors, T., Latini, F., Montelius, A., Blomquist, E. & Gudjonsson, O. (2016). Long-term evaluation of the effect of hypofractionated high-energy proton treatment of benign meningiomas by means of (11)C-L-methionine positron emission tomography. European Journal of Nuclear Medicine and Molecular Imaging, 43(8), 1432-1443
Open this publication in new window or tab >>Long-term evaluation of the effect of hypofractionated high-energy proton treatment of benign meningiomas by means of (11)C-L-methionine positron emission tomography
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2016 (English)In: European Journal of Nuclear Medicine and Molecular Imaging, ISSN 1619-7070, E-ISSN 1619-7089, Vol. 43, no 8, p. 1432-1443Article in journal (Refereed) Published
Abstract [en]

PURPOSE: To determine if (11)C-L-methionine PET is a useful tool in the evaluation of the long-term effect of proton beam treatment in patients with meningioma remnant.

METHODS: Included in the study were 19 patients (4 men, 15 women) with intracranial meningioma remnants who received hypofractionated high-energy proton beam treatment. Patients were examined with (11)C-L-methionine PET and MRI prior to treatment and after 6 months, and 1, 2, 3, 5, 7 and 10 years. Temporal changes in methionine uptake ratio, meningioma volume, meningioma regrowth and clinical symptoms throughout the follow-up period were evaluated.

RESULTS: In 17 patients the tumour volume was unchanged throughout the follow-up. The methionine uptake ratio on PET decreased over the years in most patients. In two patients the tumour remnant showed progression on MRI. In these patients, prior to the volume increase on MRI, the methionine uptake ratio increased. One patient experienced transient clinical symptoms and showed radiological evidence of a radiation-induced reaction close to the irradiated field.

CONCLUSION: Proton beam treatment is a safe and effective treatment for achieving long-term growth arrest in meningioma remnants. Follow-up with (11)C-L-methionine PET may be a valuable adjunct to, but not a replacement for, standard radiological follow-up.

Keywords
Meningioma; Proton beam treatment; Stereotactic irradiation; C-11-L-Methionine; Positron emission tomography
National Category
Cancer and Oncology Surgery Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:uu:diva-291472 (URN)10.1007/s00259-016-3310-z (DOI)000378005000007 ()26819102 (PubMedID)
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2017-11-30Bibliographically approved
Cai, Y., Edin, F., Jin, Z., Alexsson, A., Gudjonsson, O., Liu, W., . . . Li, H. (2016). Strategy towards independent electrical stimulation from cochlear implants: Guided auditory neuron growth on topographically modified nanocrystalline diamond. Acta Biomaterialia, 31, 211-220
Open this publication in new window or tab >>Strategy towards independent electrical stimulation from cochlear implants: Guided auditory neuron growth on topographically modified nanocrystalline diamond
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2016 (English)In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 31, p. 211-220Article in journal (Refereed) Published
Abstract [en]

Cochlear implants (CI) have been used for several decades to treat patients with profound hearing loss. Nevertheless, results vary between individuals, and fine hearing is generally poor due to the lack of discrete neural stimulation from the individual receptor hair cells. A major problem is the deliverance of independent stimulation signals to individual auditory neurons. Fine hearing requires significantly more stimulation contacts with intimate neuron/electrode interphases from ordered axonal re-growth, something current CI technology cannot provide.

Here, we demonstrate the potential application of micro-textured nanocrystalline diamond (NCD) surfaces on CI electrode arrays. Such textured NCD surfaces consist of micrometer-sized nail-head-shaped pillars (size 5 5 lm2) made with sequences of micro/nano-fabrication processes, including sputtering, photolithography and plasma etching.

The results show that human and murine inner-ear ganglion neurites and, potentially, neural progenitor cells can attach to patterned NCD surfaces without an extracellular matrix coating. Microscopic methods revealed adhesion and neural growth, specifically along the nail-head-shaped NCD pillars in an ordered manner, rather than in non-textured areas. This pattern was established when the inter-NCD pillar distance varied between 4 and 9 lm.

The findings demonstrate that regenerating auditory neurons show a strong affinity to the NCD pillars, and the technique could be used for neural guidance and the creation of new neural networks. Together with the NCD’s unique anti-bacterial and electrical properties, patterned NCD surfaces could provide designed neural/electrode interfaces to create independent electrical stimulation signals in CI electrode arrays for the neural population.

National Category
Medical Materials Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-266956 (URN)10.1016/j.actbio.2015.11.021 (DOI)000370086100019 ()26593784 (PubMedID)
Funder
EU, FP7, Seventh Framework Programme, 603029
Available from: 2015-11-14 Created: 2015-11-14 Last updated: 2017-12-01Bibliographically approved
Rodriguez-Lorenzo, A., Rydevik Mani, M., Thor, A., Gudjonsson, O., Marklund, N., Olerud, C. & Ekberg, T. (2014). Fibula osteo-adipofascial flap for reconstruction of a cervical spine and posterior pharyngeal wall defect. Microsurgery, 34(4), 314-318
Open this publication in new window or tab >>Fibula osteo-adipofascial flap for reconstruction of a cervical spine and posterior pharyngeal wall defect
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2014 (English)In: Microsurgery, ISSN 0738-1085, E-ISSN 1098-2752, Vol. 34, no 4, p. 314-318Article in journal (Refereed) Published
Abstract [en]

When reconstructing combined defects of the cervical spine and the posterior pharyngeal wall the goals are bone stability along with continuity of the aerodigestive tract. We present a case of a patient with a cervical spine defect, including C1 to C3, associated with a posterior pharyngeal wall defect after excision of a chordoma and postoperative radiotherapy. The situation was successfully solved with a free fibula osteo-adipofascial flap. The reconstruction with a fibula osteo-adipofascial flap provided several benefits in comparison with a fibula osteo-cutaneous flap in our case, including an easier insetting of the soft tissue component at the pharyngeal level and less bulkiness of the flap allowing our patient to resume normal deglutition.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-216206 (URN)10.1002/micr.22217 (DOI)000333808000012 ()24375861 (PubMedID)
Available from: 2014-01-20 Created: 2014-01-20 Last updated: 2018-05-25Bibliographically approved
Nyberg, G., Kinnefors, A., Gudjonsson, O., Svedberg, A., Edfeldt, L. & Rask-Andersen, H. (2007). Hjärnstamsimplantat kan återge hörsel. Behandling av dövhet vid dubbelsidiga akustikusneurinom: Brain stem implant can restore hearing. Treatment of deafness in bilateral acoustic neuroma. Läkartidningen, 104(47), 3553-3556
Open this publication in new window or tab >>Hjärnstamsimplantat kan återge hörsel. Behandling av dövhet vid dubbelsidiga akustikusneurinom: Brain stem implant can restore hearing. Treatment of deafness in bilateral acoustic neuroma
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2007 (Swedish)In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 104, no 47, p. 3553-3556Article in journal (Refereed) Published
Abstract [en]

Auditory brain stem implant (ABI) is a method to restore some hearing in patients with bilateral acoustic neuroma (vestibular schwannoma) or neurofibromatosis type 2 (NF 2). The ABI device may re-establish some hearing improving patient lip reading, awareness of sound and facilitate speech production after onset of total deafness. Today ABI is an established technique for treatment of deafness in patients with NF 2, with a low complication rate. New indications are inner ear malformations with lacking auditory nerve and severe calcification of the cochlea in children. Additional improvements in technical design and more knowledge about the microanatomy and function of the central auditory pathways, including the cochlear nucleus, will most likely lead to still better results in the near future.

Abstract [sv]

Neurofibromatos typ 2 (NF 2) är en sjukdom som i de flesta fall, förr eller senare, leder till total dövhet.

Behandling med hjärnstamsimplantat är ett sätt att återställa viss hörsel hos många patienter med denna sjukdom.

Med hjärnstamsimplantat omformas ljud till elektriska signaler som stimulerar hörselkärnan direkt i hjärnstammen.

Med hjärnstamsimplantat kan patienten uppfatta omgivningsljud, få förbättrad läppavläsning och därmed lättare vidmakthålla röstläge, betoning och artikulation när den egna rösten inte kan förnimmas.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:uu:diva-15363 (URN)18203590 (PubMedID)
Available from: 2008-02-20 Created: 2008-02-20 Last updated: 2017-12-08Bibliographically approved
Gudjonsson, O., Bergstrom, M., Kristjansson, S., Wu, F., Nyberg, G., Fasth, K.-J. & Langstrom, B. (2001). Analysis of 76Br-BrdU in DNA of brain tumors after av PET study does not support its use as a proliferation marker. Nuclear Medicine and Biology, 28, 59
Open this publication in new window or tab >>Analysis of 76Br-BrdU in DNA of brain tumors after av PET study does not support its use as a proliferation marker
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2001 (English)In: Nuclear Medicine and Biology, Vol. 28, p. 59-Article in journal (Refereed) Published
Identifiers
urn:nbn:se:uu:diva-56138 (URN)
Note
Adress: Långström B, Univ Uppsala, Inst Chem, Box 531, S-75121 Uppsala, SwedenAvailable from: 2008-06-17 Created: 2008-06-17 Last updated: 2011-01-14
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