Biomedical subjects

M Arvidsson

Publications and source records attributed to M Arvidsson.

13 recordsLinked to original sources

PubMed2006

Musculoskeletal disorders among female and male air traffic controllers performing identical and demanding computer work.

Operators with identical, demanding computer work (90 female and 97 male air traffic controllers) were found to have high prevalences of disorders (assessed by questionnaire and physical examination) in neck, shoulders and upper back. In spite of the identical work, the women displayed higher prevalences than the men (e.g. neck diagnoses 21% vs. 4%). Disorders in elbows, wrists and hands were less common, with similar rates in both genders. Generally, the psychosocial work environment (assessed by questionnaire) was found to be good, but with large inter-individual variation. Women experienced lower decision latitude than men, particularly regarding influence and freedom at work, but perceived higher social support. Physically, the work was characterized by relatively low angular velocities of upper arms (measured by inclinometry) and wrists (right: < 1 degrees/s during 19% of time, measuring by goniometry), dynamic muscular activities and high time fractions of rest in the trapezius and forearm extensor muscles (measuring by electromyography). There were only minor differences between the genders.

Accidents, Aviation↗

PubMed2004

A double-blind, placebo-controlled birch allergy vaccination study: inhibition of CD23-mediated serum-immunoglobulin E-facilitated allergen presentation.

BACKGROUND: The clinical efficacy of specific allergy vaccination (SAV), previously called specific immunotherapy is well documented. The working mechanism of this treatment is not completely known at present. Allergen-specific CD4+ T lymphocytes are activated at extremely low allergen concentrations in vivo possibly as a result of serum IgE-facilitated allergen presentation (S-FAP). Previously, we have shown that this process can be inhibited by long-term birch SAV sera. METHODS: In the present study, we have analysed sera from birch-allergic patients in a randomized double-blind, placebo-controlled clinical trial for their ability to mediate S-FAP. Birch-specific IgE levels were not changed after SAV. Bet v 1-specific IgE levels, however, were significantly decreased (P<0.05) and Bet v 1-specific IgG4 levels were strongly increased after SAV (P<0.001). None of these changes were observed in the placebo group. When the sera were tested for their ability to induce S-FAP, a complete abrogation of this effect was noted in the sera from patients receiving active treatment (P<0.001), but not in the control group. This inhibition of S-FAP seemed to be associated with the reduction in the ratio between Bet v 1-specific IgE and IgG4 antibodies in serum, but a clear correlation could not be demonstrated. CONCLUSION: In conclusion, the present study clearly shows that SAV leads to an inhibition of the S-FAP needed to obtain optimal T cell activation at the low allergen concentrations present in vivo. This novel mechanism may explain the increased allergen threshold levels found in allergen provocation tests and the reduction of late-phase reactions observed after SAV.

Allergens↗

PubMed2004

Haplotypes of the interleukin-4 receptor alpha chain gene associate with susceptibility to and severity of atopic asthma.

BACKGROUND: Development of asthma is likely to depend on a complex interaction between environmental and genetic factors. Several groups have suggested the gene of the IL-4 receptor alpha chain (IL4R) as a candidate gene for the development of asthma, although association with single polymorphisms has shown contradicting results. OBJECTIVE: We chose to analyse IL4R gene haplotypes and assess their possible relevance in susceptibility to asthma and to certain clinical phenotypes. METHODS: IL4R gene haplotypes were analysed, based on the three markers C-3223T, Q551R and I50V, using the expectation-maximization algorithm, in 170 atopic asthma patients and 350 controls, all adult Swedish Caucasians. RESULTS: Our data showed significantly higher levels of soluble IL-4R (sIL-4R) in asthma patients compared with controls (P<0.0001). Furthermore, we showed a significant association between the IL4R haplotype containing the alleles T-3223, V50 and R551 (TVR) of the IL4R gene, and susceptibility to atopic asthma, with a frequency of 6.5% in the patients compared with 1% in the controls (P<0.0005). A subgroup of patients with heterozygous or homozygous state for the T-3223, V50 and R551 alleles, also had lower levels of sIL-4R in their circulation compared with patients with homozygous state in the C-3223, I50 and Q551 alleles (P<0.05) and showed less severe asthma according to lung function test (P<0.05). Analysis of single markers showed the T-3223 IL4R allele to associate with lower serum levels of sIL-4 receptor (P<0.0001) and patients carrying the T allele also had more symptoms of active asthma (wheezing, P<0.01; coughing, P<0.05 and breathing difficulties, P<0.01). CONCLUSION: Our data suggest that asthmatic patients with low levels of sIL-4 receptor may represent a genetically distinct subgroup of atopic asthma. TVR haplotype analyses confirm the importance of IL4R as a candidate gene for susceptibility to asthma. This finding may have implications for the understanding of the pathogenesis of asthma and possibly for the development of more specific therapies.

Adolescent↗

PubMed2004

The effect of specific immunotherapy on the expression of costimulatory molecules in late phase reaction of the skin in allergic patients.

BACKGROUND: Specific immunotherapy (SIT) modulates immune responses to allergens resulting in improvement of allergic symptoms. However, the mechanisms behind the clinical changes are not clear. Participation of costimulatory molecules on antigen-presenting cells and T cells in the process of antigen recognition is suggested to be of essential importance. The SIT effect on expression of costimulatory molecules has not been earlier examined. METHODS: Forty-one birch-allergic patients were treated with SIT or placebo. After 1 year of treatment skin biopsies were obtained 24 h following allergen challenge. Sections were stained with antibodies against: EG2 (eosinophils), CD4 (T cells), CD68 (macrophages), CD1a (Langerhans cells), CD28 (on T cells) and costimulatory molecules (CD80, CD86). RESULTS: Following allergen challenge number of the CD4(+) and CD68(+) cells increased significantly (P=0.002, 0.0001, respectively) in the placebo, but not in the SIT-treated patients. The difference between groups was significant (P=0.003, 0.01, respectively). The numbers of EG2(+) cells increased significantly in both groups. CD80(+) cell numbers increased in the placebo (P=0.01) but not in the SIT group. The number of CD86(+) cells increased in both groups (placebo, P=0.001; SIT, P=0.01) but significantly less in the SIT group (P=0.05). The numbers of CD28(+) cells increased in the placebo (P=0.001) but remained unchanged in the SIT group. The difference between the groups was significant (P=0.05). CONCLUSION: There were lower numbers of cells expressing costimulatory molecules in SIT-treated than in placebo-treated patients. Decreased costimulation may lead to diminished immune response following allergen exposure. This could be an important factor contributing to the clinical improvement after SIT.

Adult↗

PubMed2002

Asthma and asthma-like disorder, a 5-year follow-up study.

Consecutive adult patients (n = 70) referred for investigation of suspected asthma were reinvestigated after 5 years with the same diagnostic procedures (airway symptom score, spirometry, methacholine test) as used at the initial investigation. The same diagnostic criteria for asthma, asthma-like disorder (current asthma-like symptoms but negative asthmatests)and chronicobstructive pulmonary disease (COPD) were used at both visits. At the first visit 39/70 patients (56%) fulfilled the asthma criteria, 21/70 (27%) fulfilled the asthma-like criteria and 5/70 (7%) the COPD criteria. Due to lack of current symptoms 5/70 (7%) could not be classified. 5/70 patients (7%) were smokers, however, in the majority (72%) smoke was not tolerated as it induced asthma-like symptoms. At the investigation, 5 years later, 30/39 patients (76%) still fulfilled the asthma criteria and 12/21 patients (57%) still fulfilled the asthma-like criteria. At the 5-year investigation, 10% of patients in the asthma group now fulfilled the asthma-like criteria and 10% of patients in the asthma-like group fulfilled the asthma criteria. It is concluded that asthma as well an asthma-like syndrome may persist for 5 years or more. It is also concluded thatthe two disorders are closely related as patients in the asthma group over time could move into the diagnostic criteria ofthe asthma-like disorder and vice versa.

Adolescent↗

PubMed2000

NURR1 mutations in cases of schizophrenia and manic-depressive disorder.

Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.

Alleles↗

PubMed1999

Activity of the Nurr1 carboxyl-terminal domain depends on cell type and integrity of the activation function 2.

Nurr1, a member of the nuclear hormone receptor superfamily, was recently demonstrated to be of critical importance in the developing central nervous system, where it is required for the generation of midbrain dopamine cells. Nuclear receptors encompass a transcriptional activation function (activation function 2; AF2) within their carboxyl-terminal domains important for ligand-induced transcriptional activation. Since a Nurr1 ligand remains to be identified, the role of the Nurr1 AF2 region in transcriptional activation is unclear. However, here we show that the Nurr1 AF2 contributes to constitutive activation independent of exogenously added ligands in human embryo kidney 293 cells and in neural cell lines. Extensive mutagenesis indicated a crucial role of the AF2 core region for transactivation but also identified unique features differing from previously characterized receptors. In addition, Nurr1 did not appear to interact with, and was not stimulated by, several previously identified coactivators such as the steroid receptor coactivator 1. In contrast, adenovirus protein E1A, stably expressed in 293 cells, was shown to contribute to AF2-dependent activation. Finally, while the AF2 core of RXR is required for ligand-induced transcriptional activation by Nurr1-RXR heterodimers, the functional integrity of Nurr1 AF2 core is not critical. These results establish that the ligand binding domain of Nurr1 has intrinsic capacity for transcriptional activation depending on cell type and mode of DNA binding. Furthermore, these results are consistent with the possibility that gene expression in the central nervous system can be modulated by an as yet unidentified ligand interacting with the ligand binding domain of Nurr1.

Adenovirus E1A Proteins↗

PubMed1999

Fate of mesencephalic AHD2-expressing dopamine progenitor cells in NURR1 mutant mice.

The orphan nuclear receptor NURR1 was previously demonstrated to be required for the generation of mesencephalic dopamine (DA) cells. However, even in the absence of NURR1, which is normally expressed as cells become postmitotic, neuronal differentiation is induced and expression of several genes detected in developing dopamine cells appears normal during early stages of development. These include the homeobox transcription factors engrailed and Ptx-3 as well as aldehyde dehydrogenase 2, here defined as the earliest marker identified in developing DA cells, expressed already in mitotic DA progenitors. We have used the expression of these dopaminergic markers, retrograde axonal tracing, and apoptosis analyses to study the fate of the DA progenitor cells in the absence of NURR1. We conclude that NURR1 plays a critical role in the maturation, migration, striatal target area innervation, and survival of differentiating mesencephalic DA cells.

Aldehyde Dehydrogenase↗

PubMed1999

Exercise-induced respiratory symptoms are not always asthma.

Eighty-eight patients with a history of exercise-induced respiratory symptoms performed a maximal exercise test in order to study the reasons for stopping the test. There was a wide range of percentage maximal fall in peak expiratory flow (PEF), from minus 3% to 63%, mean 11%, recorded 0-30 min, mean 12 min after the break. In the controls the maximal decrease was 0-16%, mean 6%. Diagnostic criteria for asthma were fulfilled by 48 patients (55%). Of these patients 42% had a fall in PEF > or = 15% (exercise-induced asthma). Of the non-asthma patients 10% had a fall > or = 15%. The most common reason for stopping the exercise in the asthma group was breathing troubles (46%), the most common reason in the non-asthma group was chest pain/discomfort (35%). In about 20% of the patients dizziness and/or pricking sensations in arms or legs indicated hyperventilation as an additional reason for stopping the exercise. It is concluded that other kinds of reaction, than bronchial obstruction such as breathing troubles not directly related to bronchial obstruction and chest pain, may be important factors that can restrict physical capacity in patients with exercise-induced respiratory symptoms.

Adolescent↗

PubMed1998

Low symptomatic load in Crohn's disease with surgery and medicine as complementary treatments.

BACKGROUND: The treatment of Crohn's disease has changed owing to the recognition of its chronicity. Medical maintenance treatment and limited resections have evolved as major concepts of management, regarded as complementary, and both aim at reducing the symptoms. METHODS: We investigated the symptomatic load in Crohn's disease as reflected in a cross-sectional study of the symptom index, physicians' assessment, and the patients' perception of health. A cohort of 212 patients from the primary catchment area and 125 referred patients were studied. RESULTS: Of catchment area patients, 83% were receiving medication, and the annual rate of abdominal surgery was 5.7%. Corresponding figures for the referred patients were 82% and 10.3%. According to the symptom index, 87% of catchment area patients were in remission or had only mild symptoms; according to the physicians' assessment, 90% were. The patients' median perception of health was 90% of perfect health according to the visual analogue scale. The figures were similar for referred patients, except that referrals were considered more diseased by the physician. CONCLUSION: The great majority of patients with Crohn's disease are able to live in remission or experience only mild symptoms.

Adult↗

PubMed1997

Stroop and mood/memory measures in the study of unconscious "oneness".

Adaptive behavior following subliminal stimulation with "Mommy and I are One" (MIO) is a poorly understood finding. Positive mood may explain adaptive behavior, but we replicated an earlier finding that effects can also include negative mood. Color naming in a Stroop paradigm was slower on "symbiosis" words (Cohen's d = .19 to .56). Perhaps a "oneness" structure if primed has different affective correlates in different participants.

Affect↗

PubMed1995

Evaluation of volume selection methods in in vivo MRS. Design of a new test phantom.

In vivo MR spectroscopy (MRS) requires some kind of volume selection method to be able to measure the signal from a selected part of the body. To be able to interpret the spectra correctly, the quality of the volume selection must be investigated for each new MRS application using phantom measurements. A new phantom, especially suitable for precision measurements of the volume selection performance, is presented. It contains a small, remotely controlled signal source placed inside a larger vessel. This principle can be applied to various body regions, coil types and nuclei. The measurement conditions are close to the clinical situation. The phantom does not have to be repositioned during a signal profile measurement and the signal contribution from each point along the profile is determined regarding sign and amplitude.

Brain↗

PubMed1994

Posterolateral lumbar fusion. Outcome of 71 consecutive operations after 4 (2-7) years.

We report the outcome of 71 consecutive posterolateral lumbar fusions without spinal instrumentation. The indication for the operation was spondylolysis-olisthesis, degenerative disc disease/facet joint arthrosis, or pain after prior laminectomy. Concerning pain relief, 29/43 patients with spondylolysis-olisthesis were classified as good. The corresponding figures in the group with degenerative disc disease and/or facet joint arthrosis were 8/16 patients and in the group with pain post-laminectomy, 6/12 patients. No surgical complications were noted. In the total material 54 patients had a solid fusion, as defined by radiographic osseous trabecular bridging at all intended levels. One-level fusions tended to heal solidly in a higher frequency than two-level fusions. For the spondylolysis-olisthesis group, healed fusion correlated with a good clinical result. Such a correlation could not be verified for the other diagnostic groups. We conclude that non-instrumented posterolateral lumbar fusion is a valid method for treating low-grade spondylolysis-olisthesis, especially when the aim is to fuse a single level. Improved patient selection methods are required in fusion for degenerative disc disease and pain after laminectomy.

Adolescent↗