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Dive into the research topics where Olov Norlén is active.

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Featured researches published by Olov Norlén.


British Journal of Surgery | 2013

Outcome after resection and radiofrequency ablation of liver metastases from small intestinal neuroendocrine tumours

Olov Norlén; Peter Stålberg; Jan Zedenius; Per Hellman

In patients with small intestinal neuroendocrine tumour (SI‐NET), liver resection or radiofrequency ablation (RFA) of liver metastases is performed for palliation of carcinoid syndrome, and in an effort to improve survival. Data are generally reported from case series, and no randomized trials have studied these treatments. The aim was to compare outcome after liver resection and/or RFA with that of non‐surgical treatment in patients with liver metastases from SI‐NET.


Apmis | 2005

The porA pseudogene of Neisseria gonorrhoeae--low level of genetic polymorphism and a few, mainly identical, inactivating mutations.

Magnus Unemo; Olov Norlén; Hans Fredlund

N. meningitidis is the only Neisseria species known to express two outer membrane porins, PorA and PorB. However, a porA pseudogene has been identified in N. gonorrhoeae. The present study investigated the prevalence and genetic polymorphism of this porA pseudogene in 87 different N. gonorrhoeae strains. The porA pseudogene was identified in all isolates. The pseudogene comprised 12 (5.5%), of which 10 were located in the promoter spacer, and 11 (1.0%) polymorphic nucleotide sites in the upstream segment containing the promoter region, i.e. the putative ‐10 and ‐35 sequences and the promoter spacer in‐between, and the hypothetical PorA coding sequence, respectively. A phylogenetic analysis of the upstream segment and the hypothetical coding sequence identified 36 sequence variants, of which 30 were not previously described. All strains comprised at least two identical confirmed inactivating deletions, of which one was located in the promoter region and one in the hypothetical PorA coding sequence. In conclusion, the porA pseudogene and its few inactivating mutations are widespread in the N. gonorrhoeae population and the homology with the N. meningitidis porA gene reflects their common evolutionary origin. The highly conserved N. gonorrhoeae porA pseudogene may reflect an evolutionary neutral molecular clock and may be a suitable genetic target for diagnosis of N. gonorrhoeae.


Journal of Pediatric Surgery | 2015

Risk of malignancy for each Bethesda class in pediatric thyroid nodules.

Olov Norlén; Amanda Charlton; Leba M. Sarkis; Tony Henwood; Albert Shun; Anthony J. Gill; Leigh Delbridge

PURPOSE The Bethesda classification for cytology is used to classify thyroid nodules into one of six categories, and for each category there is an implied cancer risk and also recommendation for management. Despite lack of data in children, the American thyroid association promotes the use of the same management guidelines as in adults. Our aim was to study the risk of malignancy for each Bethesda class in children with thyroid nodules. METHODOLOGY We included all patients ≤18years of age that had underwent a thyroid fine needle aspiration (FNA) at one of two centers between January 1998 and July 2013. FNA results were reclassified according to the Bethesda criteria. Histological, repeat cytological, radiological and clinical follow-up were recorded. RESULTS Fifty-six patients (66 nodules) underwent FNB. Mean age was 13.6 years. Numbers of nodules reported as BI-BVI were 7, 38, 11, 4, 3 and 3, respectively. Follow-up was achieved for 55 (83%) nodules. Twelve (18%) nodules were malignant by histology and revealed papillary (n=7), follicular (n=3) or insular thyroid cancer (n=2), The proportion of nodules with malignancy for BI-BVI was: 0%, 0%, 18%, 100%, 100% and 100%. CONCLUSION The rate of malignancy in thyroid nodules in children seems to be higher than reported in adults. The Bethesda criteria seem to accurately identify benign nodules, but other categories have a very high rate of malignancy and BIII nodules pose a particular challenge.


Annals of Surgery | 2015

No need to abandon focused parathyroidectomy : a multicenter study of long-term outcome after surgery for primary hyperparathyroidism.

Olov Norlén; Kuan Chi Wang; Yeng Kwang Tay; William Rainey Johnson; Simon Grodski; Meei J. Yeung; Jonathan W. Serpell; Stan B. Sidhu; Mark S. Sywak; Leigh Delbridge

OBJECTIVE The aim of this study was to investigate long-term outcomes after focused parathyroidectomy (FPTX) and open 4-gland parathyroid exploration (OPTX) for primary hyperparathyroidism (pHPT). BACKGROUND Concerns about increased long-term recurrence rates after FPTX in conjunction with decreased operative times for OPTX have led some groups to abandon FPTX in favor of routine 4-gland exploration. METHODS This is a multicenter retrospective cohort study of patients undergoing parathyroidectomy for pHPT from 1990 to 2013. The patient cohort was divided into 2 groups, FPTX and OPTX, based on intention-to-treat analysis. The primary outcome measure was the persistence of pHPT. Secondary outcome measures were differences in the long-term recurrence rate of persisting pHPT and surgical complications. RESULTS A total of 4569 patients (3585 females) were included. The overall persistence and recurrence rates were 2.2% and 0.9%, respectively, after a median follow-up of 6.5 years. There were 2531 FPTX cases and 2038 OPTX cases. The initial persistence rate was higher for FPTX than for OPTX (2.7% vs 1.7%, P = 0.036); however, the long-term recurrence rate was not different (5-year 0.6% vs 0.4%, log-rank P = 0.08). Complications were more common in OPTX than in FPTX (7.6% vs 3.6%, P < 0.001). CONCLUSIONS FPTX was associated with fewer operative complications and an equivalent rate of long-term recurrence than with OPTX. Although initial persistence rates were higher after FPTX than after OPTX, most were readily resolved with subsequent early reoperation. FPTX should not be abandoned in patients with positive preoperative localization.


The Journal of Clinical Endocrinology and Metabolism | 2016

Multiple and Secondary Hormone Secretion in Patients With Metastatic Pancreatic Neuroendocrine Tumours

Joakim Crona; Olov Norlén; Pantelis Antonodimitrakis; Staffan Welin; Peter Stålberg; Barbro Eriksson

CONTEXT As a group, neuroendocrine tumors (NETs) secrete many different peptide hormones, yet heretofore each NET patient is typically thought to produce at most one hormone that causes a distinct hormonal syndrome. A minority of patients have multiple hormones at diagnosis and may also develop secondary hormone secretion at a later stage. OBJECTIVES The objectives of the study were to determine the frequency and to describe the impact of multiple and secondary hormone secretion in sporadic gasteroenteropancreatic NET patients. DESIGN, SETTING, AND PARTICIPANTS This was a retrospective analysis of patients (n = 972) with gasteroenteropancreatic NET treated at Uppsala University Hospital, Uppsala, Sweden. Patients with the secretion of multiple hormones at diagnosis and/or those developing secondary hormone secretion during the disease course were identified and studied in further detail. RESULTS In pancreatic NETs (PNETs), a total of 19 of 323 patients (6%) had secretion of multiple hormones at diagnosis, and 14 of 323 (4%) had secondary changes during the disease course. These phenomena occurred exclusively in patients with an advanced disease stage, and secondary hormones were detected in a close time span with progressive disease. Patients with secondary insulin hypersecretion had increased morbidity as well as reduced survival (P < .002). In contrast, multiple and secondary hormone secretion was rarely seen in NETs of the small intestine with 0 and 1 of 603 cases, respectively. CONCLUSION Diversity of PNET hormone secretion either at diagnosis or during the disease course occurred in a minority of patients (9.3%). These phenomena had a major impact on patient outcome both through increased morbidity and mortality. Our results support that patients with metastatic PNETs should be monitored for clinical symptoms of secondary hormone secretion during the disease course.


British Journal of Surgery | 2014

Long-term outcome after parathyroidectomy for lithium-induced hyperparathyroidism

Olov Norlén; Stan B. Sidhu; Mark S. Sywak; Leigh Delbridge

The accepted management of lithium‐associated hyperparathyroidism (LiHPT) is open four‐gland parathyroid exploration (OPTX). This approach has recently been the subject of controversy. A recent study has shown very high long‐term recurrence rates after OPTX, whereas some have promoted unilateral focused parathyroidectomy as appropriate management. The aim was to evaluate long‐term outcomes after surgery for LiHPT and to assess the accuracy of preoperative imaging.


Surgery | 2014

Peritoneal carcinomatosis from small intestinal neuroendocrine tumors: Clinical course and genetic profiling

Olov Norlén; Katarina Edfeldt; Göran Åkerström; Gunnar Westin; Per Hellman; Peyman Björklund; Peter Stålberg

BACKGROUND One-fifth of all patients with small-intestinal neuroendocrine tumors (SI-NETs) present with or develop peritoneal carcinomatosis (PC). Our aim was to determine the prognosis and genetic profiles of tumors in patients with PC compared with tumors in patients without PC. METHODS We included SI-NET patients (cases with PC, n = 73, and controls without PC, n = 468) who underwent operation between 1985 and 2012. The Lyon prognostic index was used to correlate the amount of PC to survival. DNA samples from patients with (n = 8) and without (n = 7) PC were analyzed with a single-nucleotide polymorphism array (HumanOmni2.5 BeadChip, Illumina) to investigate genetic disparities between groups. RESULTS Patients with PC had poorer survival (median 5.1 years) than controls (11.1 years). An advanced postoperative Lyon prognostic index was a negative prognostic marker for survival by multivariable analysis (P = .042). Patients with and without PC clustered differently based on loss of heterozygosity and copy number variation data from single-nucleotide polymorphism array of the primary tumors (P = .042). CONCLUSION SI-NET patients with PC have poor survival, which diminishes with increasing PC load after surgery. Clustering based on copy number variation and loss of heterozygosity data suggests different genotypes in primary tumors comparing patients with and without PC.


JAMA Oncology | 2017

Association of a Prophylactic Surgical Approach to Stage IV Small Intestinal Neuroendocrine Tumors With Survival

Kosmas Daskalakis; Andreas Karakatsanis; Ola Hessman; Heather Stuart; Staffan Welin; Eva Tiensuu Janson; Kjell Öberg; Per Hellman; Olov Norlén; Peter Stålberg

Importance Primary tumor resection and mesenteric lymph node dissection in asymptomatic patients with stage IV small intestinal neuroendocrine tumors (SI-NETs) are controversial. Objective To determine the association of locoregional surgery (LRS) performed at diagnosis with outcomes in patients with asymptomatic SI-NETs and distant metastases. Design, Setting, and Participants This cohort study included asymptomatic patients with stage IV SI-NETs diagnosed from January 1, 1985, through December 31, 2015, and identified using the prospective database of SI-NETs from Uppsala University Hospital, Uppsala, Sweden. Patients included were treated at a tertiary referral center and followed up until May 31, 2016, with data from the Swedish National Patient Register. The 363 patients with stage IV SI-NETs without abdominal symptoms were divided between those who underwent prophylactic up-front surgery within 6 months from diagnosis combined with oncologic treatment (hereafter referred to as LRS group [n = 161]) and those who underwent nonsurgical treatment or delayed surgery as needed combined with oncologic treatment (hereafer referred to as delayed LRS group [n = 202]). Exposures Prophylactic up-front surgery within 6 months from diagnosis combined with oncologic treatment vs nonsurgical treatment or delayed surgery as needed combined with oncologic treatment. Main Outcomes and Measures Overall survival (OS), length of hospital stay (LOS), postoperative morbidity and mortality, and reoperation rates measured from baseline. Propensity score matching was performed between the 2 groups. Results The 363 patients included 173 women (47.7%) and 190 men (52.3%), with a mean (SD) age at diagnosis of 62.4 (11.1) years. Two isonumerical groups with 91 patients in each resulted after propensity score matching. The LRS and delayed LRS groups were comparable in median OS (7.9 years [range, 5.1-10.7 years] vs 7.6 years [range, 5.8-9.5 years]; hazard ratio [HR], 0.98; 95% CI, 0.70-1.37; log-rank P = .93) and cancer-specific survival (7.7 years [range, 4.5-10.8 years] vs 7.6 years [range, 5.6-9.7 years]; HR, 0.99; 95% CI, 0.71-1.40; log-rank P = .99). No difference was found in 30-day mortality (0 patients in both matched groups) or postoperative morbidity (2 [2.2%] vs 1 [1.1%]; P > .99), median LOS (73 days [range, 2-270 days] vs 76 days [range, 0-339 days]; P = .64) or LOS due to local tumor-related symptoms (7.0 days [range, 0-90 days] vs 11.5 days [range, 0-69 days]; P = .81), or incisional hernia repairs (4 patients [4.4%] in both groups; P > .99). Patients in the LRS group underwent more reoperative procedures (13 [14.3%]) compared with those in the delayed LRS group (3 [3.3%]) owing to intestinal obstruction (P < .001). Conclusions and Relevance Prophylactic up-front LRS conferred no survival advantage in asymptomatic patients with stage IV SI-NETs. Delayed surgery as needed was comparable in all examined outcomes and was associated with fewer reoperations for intestinal obstruction. The value of a priori LRS in the presence of distant metastases is challenged and needs to be elucidated in a randomized clinical study.


Annals of Surgical Oncology | 2014

Bethesda III thyroid nodules: the role of ultrasound in clinical decision making.

Olov Norlén; Aleksandra Popadich; Schelto Kruijff; Anthony J. Gill; Leba M. Sarkis; Leigh Delbridge; Mark S. Sywak; Stan B. Sidhu

BackgroundAssessment for thyroid nodules includes ultrasound (US) and cytology according to the Bethesda classification. There is no firm consensus regarding clinical management for nodules classified as Bethesda III. Our aim was investigate the value of US to predict malignancy in these nodules.MethodsPatients with Bethesda III nodules who underwent thyroid surgery from July 2011 to July 2013 were included. Inclusion criteria mandated that US were available for review by two observers blinded to each other’s results and histological outcome. The nodules were scrutinized with six US criteria: hypoechoic attenuation (HA), irregular margins (IM), taller than wide, microcalcifications (MC), loss of halo, and increased central vascularity. Disagreements between observers were solved by consensus.ResultsThere were 141 patients (121 women) with a mean age of 55 years. Mean nodule size was 25 mm. The malignancy rate was 13 %. Interobserver ratios were moderate to very strong for all six predictors (kappa = 0.60–0.94). However, only HA, IM, and MC were predictors of malignancy by univariate analysis (all p < 0.002). Logistic regression revealed an odds ratio of malignancy versus no malignancy for HA 4.8, IM 3.3, and MC 4.0 (all p < 0.05). The positive and negative predictive value for malignancy when having one or more of these three criteria was 22 % and 98 %, respectively.ConclusionHA, IM, and MC were predictors of malignancy in Bethesda III nodules. In addition, the negative predictive value for any of these three criteria was high; a nodule that lacks all of these three criteria is thus unlikely to be malignant.


Neuroendocrinology | 2017

DcR3, TFF3 and Midkine are Novel Serum Biomarkers in Small Intestinal Neuroendocrine Tumors.

Katarina Edfeldt; Kosmas Daskalakis; Christofer Bäcklin; Olov Norlén; Eva Tiensuu Janson; Gunnar Westin; Per Hellman; Peter Stålberg

Small intestinal neuroendocrine tumors (SI-NETs) are amine- and peptide-producing neoplasms. Most patients display metastases at the time of diagnosis; they have an unpredictable individual disease course and the tumors are often therapy resistant. Chromogranin A and 5-hydroxyindoleacetic acid are the biomarkers clinically used most often today, but there is a great need for novel diagnostic and prognostic biomarkers and new therapeutic targets. Sixty-nine biomarkers were screened in serum from 23 SI-NET patients and 23 healthy controls using the multiplex proximity ligation assay (PLA). A refined method, the proximity extension assay (PEA), was used to analyze 76 additional biomarkers. Statistical testing and multivariate classification were performed. Immunohistochemistry and ELISA were performed in an extended cohort. Using PLA, 19 biomarkers showed a significant difference in serum concentrations between patients and controls, and PEA revealed a difference in the concentrations of 17 proteins. Multivariate classification analysis revealed decoy receptor 3 (DcR3), trefoil factor 3 (TFF3), and midkine to be good biomarkers for the disease, which was confirmed by ELISA analysis. All 3 biomarkers were expressed in tumor tissue. DcR3 concentrations were elevated in patients with stage IV disease. High concentrations of DcR3 and TFF3 were correlated to poor survival. DcR3, TFF3, and midkine exhibited elevated serum concentrations in SI-NET patients compared to healthy controls, and DcR3 and TFF3 were associated with poor survival. DcR3 seems to be a marker for liver metastases, while TFF3 and midkine may be new diagnostic biomarkers for SI-NETs.

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Stan B. Sidhu

Royal North Shore Hospital

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