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Dive into the research topics where Lars Peter Nielsen is active.

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Featured researches published by Lars Peter Nielsen.


The Journal of Infectious Diseases | 2009

Incidence, Clinical Presentation, and Outcome of Progressive Multifocal Leukoencephalopathy in HIV-Infected Patients during the Highly Active Antiretroviral Therapy Era: A Nationwide Cohort Study

Frederik Neess Engsig; Ann-Brit Eg Hansen; Lars Haukali Omland; Gitte Kronborg; Jan Gerstoft; Alex Lund Laursen; Court Pedersen; Christian Backer Mogensen; Lars Peter Nielsen; Niels Obel

BACKGROUND Human immunodeficiency virus (HIV) infection predisposes to progressive multifocal leukoencephalopathy (PML). Here, we describe the incidence, presentation, and prognosis of PML in HIV-1-infected patients during the period before highly active antiretroviral therapy (HAART) (1995-1996) and during the early HAART (1997-1999) and late HAART (2000-2006) periods. METHODS Patients from a nationwide population-based cohort of adult HIV-1-infected individuals were included. We calculated incidence rates of PML and median survival times after diagnosis. We also described neurological symptoms at presentation and follow-up. RESULTS Among 4,649 patients, we identified 47 patients with PML. The incidence rates were 3.3, 1.8, and 1.3 cases per 1000 person-years at risk in 1995-1996, 1997-1999, and 2000-2006, respectively. The risk of PML was significantly associated with low CD4(+) cell count, and 47% of cases were diagnosed by means of brain biopsy or polymerase chain reaction analysis for JC virus. The predominant neurological symptoms at presentation were coordination disturbance, cognitive defects, and limb paresis. Thirty-five patients died; the median survival time was 0.4 years (95% confidence interval [CI], 0.0-0.7) in 1995-1996 and 1.8 years (95% CI, 0.6-3.0) in both 1997-1999 and 2000-2006. CD4(+) cell count >50 cells/microL at diagnosis of PML was significantly associated with reduced mortality. CONCLUSIONS The incidence of PML in HIV-infected patients decreased after the introduction of HAART. Survival after PML remains poor. In the management of PML, the main focus should be on prophylactic measures to avoid immunodeficiency.


PLOS Pathogens | 2010

Oseltamivir–Resistant Pandemic H1N1/2009 Influenza Virus Possesses Lower Transmissibility and Fitness in Ferrets

Susu Duan; David A. Boltz; Patrick Seiler; Jiang Li; Karoline Bragstad; Lars Peter Nielsen; Richard J. Webby; Robert G. Webster; Elena A. Govorkova

The neuraminidase (NA) inhibitor oseltamivir offers an important immediate option for the control of influenza, and its clinical use has increased substantially during the recent H1N1 pandemic. In view of the high prevalence of oseltamivir-resistant seasonal H1N1 influenza viruses in 2007–2008, there is an urgent need to characterize the transmissibility and fitness of oseltamivir-resistant H1N1/2009 viruses, although resistant variants have been isolated at a low rate. Here we studied the transmissibility of a closely matched pair of pandemic H1N1/2009 clinical isolates, one oseltamivir-sensitive and one resistant, in the ferret model. The resistant H275Y mutant was derived from a patient on oseltamivir prophylaxis and was the first oseltamivir-resistant isolate of the pandemic virus. Full genome sequencing revealed that the pair of viruses differed only at NA amino acid position 275. We found that the oseltamivir-resistant H1N1/2009 virus was not transmitted efficiently in ferrets via respiratory droplets (0/2), while it retained efficient transmission via direct contact (2/2). The sensitive H1N1/2009 virus was efficiently transmitted via both routes (2/2 and 1/2, respectively). The wild-type H1N1/2009 and the resistant mutant appeared to cause a similar disease course in ferrets without apparent attenuation of clinical signs. We compared viral fitness within the host by co-infecting a ferret with oseltamivir-sensitive and -resistant H1N1/2009 viruses and found that the resistant virus showed less growth capability (fitness). The NA of the resistant virus showed reduced substrate-binding affinity and catalytic activity in vitro and delayed initial growth in MDCK and MDCK-SIAT1 cells. These findings may in part explain its less efficient transmission. The fact that the oseltamivir-resistant H1N1/2009 virus retained efficient transmission through direct contact underlines the necessity of continuous monitoring of drug resistance and characterization of possible evolving viral proteins during the pandemic.


PLOS ONE | 2013

The Short- and Long-Term Risk of Stroke after Herpes Zoster - A Nationwide Population-Based Cohort Study

Nandini Sreenivasan; Saima Basit; Jan Wohlfahrt; Björn Pasternak; Tina Noergaard Munch; Lars Peter Nielsen; Mads Melbye

Background and Objective Varicella zoster virus (VZV) is known to cause VZV vasculopathy, which may be associated with stroke. A recent study found an increased risk of stroke within one year of herpes zoster. We aimed to investigate the short and long-term effects of herpes zoster on the risk of stroke. Methods Using Danish national registers, we constructed a cohort consisting of all Danish adults ≥18 years old between 1995 and 2008 (n = 4.6 million; person-years of follow-up = 52.9 million). Individual-level information on prescriptions for herpes zoster antiviral treatment and diagnoses of stroke was obtained from national registers. We compared the risk of stroke in persons who had received the specific dosage of acyclovir for herpes zoster with persons who had never received antiviral treatment by Poisson regression. Results During follow-up, 2.5% received treatment for herpes zoster and 5.0% were diagnosed with stroke. Individuals who had received medication had a 127% (95% CI 83–182%) increased risk the first two weeks, 17% (CI 9–24%) between two weeks and one year, and 5% (2–9%) after the first year. The increased risk was greatest in the youngest age group (<40). To control for healthcare-seeking behaviour, we conducted parallel analyses investigating the risk of selected fractures after herpes zoster and found no similar increased risks. Conclusions This large nationwide cohort study found an increased risk of stroke after treatment for herpes zoster. Although the short-term risk was particularly high, we cannot rule out the possibility of a small but important long-term risk.


Clinical Endocrinology | 1999

Muscle mass and function in thyrotoxic patients before and during medical treatment

Helene Nørrelund; Karen Yde Hove; Eva Brems‐Dalgaard; Anne Grethe Jurik; Lars Peter Nielsen; Søren Nielsen; Steen Nielsen; Jens Otto Lunde Jørgensen; Jørgen Weeke; Niels Møller

Development of muscle weakness and atrophy are well known complications of thyrotoxicosis, although little is known about its clinical course. The present longitudinal study was therefore undertaken to monitor muscle mass and strength before and during treatment of hyperthyroidism.


Respiratory Medicine | 1999

Salmeterol reduces the need for inhaled corticosteroid in steroid-dependent asthmatics.

Lars Peter Nielsen; B. Pedersen; P. Faurschou; F. Madsen; J.T.R. Wilcke; Ronald Dahl

Previous results have demonstrated addition of long-acting beta2-adrenergic agonists to be beneficial in asthma patients already receiving inhaled corticosteroid. The purpose of this study was to determine, qualitatively as well as quantitatively, the steroid-sparing properties of salmeterol in stable asthma patients receiving maintenance inhaled corticosteroids (800-1600 microg day(-1)). In these patients, the daily dose of beclomethasone dipropionate was reduced by 200 microg each week until asthma deteriorated, with the minimal acceptable dose (MAD) being defined as the dose one step above deterioration (sensitivity period). Following this, patients received three times the MAD for 2 weeks. Patients were randomized to receive either salmeterol 50 microg twice daily or placebo and the MAD was again determined (treatment period). Forced expiratory volume in 1 sec (FEV1) was measured each week. Morning and evening peak expiratory flow (PEF), symptom score and use of bronchodilator were recorded each day. Fifteen patients received salmeterol and 19 placebo. The MAD was significantly lower in the salmeterol group compared with placebo during the treatment period (P<0.01). A 50% reduction of the MAD was achieved by more patients treated with salmeterol than placebo (P = 0.001). Salmeterol caused a significantly greater reduction in daytime symptom score and use of as-needed beta2-agoinist therapy between sensitivity and treatment periods compared with placebo (P<0.05 for both). The results demonstrate, that the addition of salmeterol to corticosteroid treatment offers a clinically relevant potential for reduction of inhaled corticosteroid dose in steroid sensitive asthmatics.


Journal of Virological Methods | 2011

A simple method for the parallel deep sequencing of full influenza A genomes

Marie-Louise Kampmann; Sarah L. Fordyce; María C. Ávila-Arcos; Morten Rasmussen; Lars Peter Nielsen; M. Thomas P. Gilbert

Given the major threat of influenza A to human and animal health, and its ability to evolve rapidly through mutation and reassortment, tools that enable its timely characterization are necessary to help monitor its evolution and spread. For this purpose, deep sequencing can be a very valuable tool. This study reports a comprehensive method that enables deep sequencing of the complete genomes of influenza A subtypes using the Illumina Genome Analyzer IIx (GAIIx). By using this method, the complete genomes of nine viruses were sequenced in parallel, representing the 2009 pandemic H1N1 virus, H5N1 virus from human and H1N1 virus from swine, on a single lane of a GAIIx flow cell to an average depth of 122-fold. This technique can be applied to cultivated and uncultivated virus.


American Journal of Rhinology | 1997

A comparison of aqueous suspensions of budesonide nasal spray (128 micrograms and 256 micrograms once daily) and fluticasone propionate nasal spray (200 micrograms once daily) in the treatment of adult patients with seasonal allergic rhinitis.

Martin A. Stern; Ronald Dahl; Lars Peter Nielsen; Bente Pedersen; Camilla Schrewelius

The efficacy of aqueous suspensions of budesonide nasal spray and fluticasone propionate nasal spray, in the treatment of seasonal allergic rhinitis, was compared in a large, placebo-controlled, two-center study. A 1-week baseline period was followed by a 4- to 6-week treatment period during which 635 adult patients, aged 18–72 years, were randomized to receive either placebo, budesonide 128 μg, or 256 μg once daily, or fluticasone propionate, 200 μg once daily. Nasal and eye symptoms, overall treatment efficacy and safety assessments were made during the study period. Combined, as well as individual, nasal symptoms were significantly improved in all three active treatment groups compared with placebo therapy. Treatment with 256 μg/day of budesonide was found to be significantly more effective in reducing the sneezing score compared with 200 μg/day of fluticasone propionate. Analysis of symptom scores on days when the pollen count was greater than 10 grains/m3 revealed 256 μg/day of budesonide therapy to be significantly more effective in reducing combined symptom scores as well as the individual scores for sneezing and runny nose, compared with 200 μg/day fluticasone propionate. The higher dose of budesonide (256 μg/day) was also more effective than the lower dose (128 μg/day) in reducing sneezing scores and statistical significance was almost reached for the reduction in combined symptom and runny nose scores. Substantial or total control of symptoms was achieved by 31.4%, 85.3%, 88.4%, and 81.9% of patients receiving placebo, 128 μg/day of budesonide, 256 μg/day of budesonide, and 200 μg/day of fluticasone propionate, respectively. The incidence of adverse events was low in all treatment groups. In conclusion, both budesonide and fluticasone propionate treatments were effective and well-tolerated in the treatment of seasonal allergic rhinitis. However, 256 μg/day of budesonide tended to be more effective than 200 μg/day of fluticasone propionate and 128 μg/day of budesonide, especially when patients were exposed to a higher pollen load.


Emerging Infectious Diseases | 2012

Serious Invasive Saffold Virus Infections in Children, 2009

Alex Christian Yde Nielsen; Blenda Böttiger; Jytte Banner; Thomas Hoffmann; Lars Peter Nielsen

This virus might have caused previously unexplained cerebral infections and deaths in children.


Allergy | 2008

Eosinophil markers in seasonal allergic rhinitis : Intranasal fluticasone propionate inhibits local and systemic increases during the pollen season

Lars Peter Nielsen; T. Bjerke; M. B. Christensen; M. Skamling; C. G. B. Peterson; Niels Mygind; Ronald Dahl

Background The purpose was to study activation markers of the eosinophil granulocytes in seasonal allergic rhinitis, and the impact of topical steroid therapy thereupon.


Scandinavian Journal of Infectious Diseases | 2012

Late presenters, repeated testing, and missed opportunities in a Danish nationwide HIV cohort

Marie Helleberg; Frederik Neess Engsig; Gitte Kronborg; Alex Lund Laursen; Gitte Pedersen; Olav Larsen; Lars Peter Nielsen; Janne Jensen; Jan Gerstoft; Niels Obel

Abstract Background: We aimed to estimate the incidence and predictors of late presentation among human immunodeficiency virus (HIV)-infected individuals in Denmark. Methods: Incidence rates (IR) of presentation with advanced HIV (CD4 < 200 cells/μl and/or acquired immune deficiency syndrome (AIDS)) and late presentation (CD4 < 350 cells/μl and/or AIDS) were calculated per 100,000 population aged 16–60 y. Mortality rate ratios (MRR) were estimated using Poisson regression analysis. Results: Three thousand and twenty-seven individuals were diagnosed with HIV in 1995–2009; 34.7% presented with advanced HIV and 51.2% were late presenters. The IR of HIV was stable (6.2/100,000 population), but IR of presentation with advanced HIV declined during the study period from 2.2 (95% confidence interval (CI) 1.8–2.8) to 1.1 (95% CI 0.8–1.5). Age >50 y, heterosexuals of non-Danish origin, ‘other’ route of transmission, and diagnosis before 2002 were associated with an increased risk of presenting with advanced HIV, whereas a negative HIV test prior to diagnosis was associated with a significantly reduced risk. A total of 414 individuals (40.0%) had attended a hospital 1–3 y before presenting with advanced HIV. After 2002 the proportion of men who have sex with men with a negative HIV test prior to diagnosis increased (incidence rate ratio (IRR) 1.3, 95% CI 1.1–1.6), coinciding with a reduction in IR of presentation with advanced HIV. Mortality rates were increased the first 2 y following presentation with advanced HIV (MRR 5.9, 95% CI 3.6–9.4 and MRR 2.5, 95% CI 1.4–4.1, respectively). Conclusion: In a setting with a low HIV prevalence, the rate of presentation with advanced HIV can potentially be reduced by repeated HIV testing of individuals with a continuous high risk of transmission and by adhering to guidelines for targeted HIV testing.

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Ronald Dahl

Odense University Hospital

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Niels Obel

Copenhagen University Hospital

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Court Pedersen

Odense University Hospital

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Jan Gerstoft

University of Copenhagen

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Gitte Kronborg

Copenhagen University Hospital

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Sarah Mollerup

University of Copenhagen

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Tobias Mourier

University of Copenhagen

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