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Biomedical subjects

Gunnar Andersson

Publications and source records attributed to Gunnar Andersson.

12 recordsLinked to original sources
PubMed2006

Effects of growth differentiation factor-5 on the intervertebral disc--in vitro bovine study and in vivo rabbit disc degeneration model study.

STUDY DESIGN: In vitro studies on the effects of recombinant human growth and differentiation factor-5 (rhGDF-5) on matrix metabolism of bovine intervertebral disc cells and an in vivo study on the effect of rhGDF-5 in the rabbit anular puncture model. OBJECTIVE: To determine the reparative capacity of rhGDF-5 on the intervertebral disc. SUMMARY OF BACKGROUND DATA: The in vitro and in vivo effects of rhGDF-5, a crucial protein in the developing musculoskeletal system, on repair of the degenerated intervertebral disc remain unidentified. METHODS: In vitro, bovine nucleus pulposus and anulus fibrosus cells were cultured with or without rhGDF-5 (100 or 200 ng/mL). On days 7, 14, and 21, the contents of deoxyribonucleic acid and proteoglycan, and the synthesis of proteoglycan and collagen were assessed. In vivo, 16 adolescent New Zealand white rabbits received anular punctures in 2 lumbar discs. Four weeks later, phosphate buffered saline or rhGDF-5 (10 ng, 1 and 100 mug) was injected into the nucleus pulposus. The rabbits were followed up for 16 weeks for disc height, magnetic resonance imaging, and histologic grading. RESULTS: In vitro, rhGDF-5 increased the deoxyribonucleic acid and proteoglycan contents of both cell types significantly after day 14. rhGDF-5 at 200 ng/mL significantly stimulated proteoglycan synthesis (nucleus pulposus: +138%, anulus fibrosus: +24%) and collagen synthesis (nucleus pulposus: +95%, anulus fibrosus: +23%) at day 21. In vivo, the injection of rhGDF-5 resulted in a restoration of disc height, improvement of magnetic resonance imaging scores, and histologic grading scores with statistical significance (P < 0.05-0.001). CONCLUSION: A single injection of rhGDF-5 has a reparative capacity on intervertebral discs, presumably based on its effects to enhance extracellular matrix production in vitro.

Animals↗
PubMed2006

Osteogenic protein-1 injection into a degenerated disc induces the restoration of disc height and structural changes in the rabbit anular puncture model.

STUDY DESIGN: In vivo study of the effect of injection of osteogenic protein-1 (OP-1) on a rabbit anular needle puncture model of intervertebral disc (IVD) degeneration. OBJECTIVE: To study radiographic, magnetic resonance imaging (MRI), biochemical, and histologic changes in the rabbit IVD after injection of OP-1 into the nucleus pulposus in a needle puncture disc degeneration model. SUMMARY OF THE BACKGROUND DATA: Growth factors, such as OP-1, have the ability to stimulate synthesis of proteoglycans and collagen in vitro. The in vivo injection of OP-1 into the normal rabbit IVD has increased disc height and proteoglycan content in the anulus fibrosus and nucleus pulposus. However, to our knowledge, no attempts have yet been made to determine the effects of these growth factors in an in vivo model of disc degeneration. METHODS: New Zealand adolescent white rabbits (n = 90, 8 for baseline evaluation, 82 at 8 times) received an anular puncture in 2 noncontiguous discs with an 18-gauge needle to induce disc degeneration. Four weeks later, either 5% lactose (10 microL) or OP-1 (100 microg in 10 microL 5% lactose) was injected into the center of the nucleus pulposus. The disc height was followed radiographically for up to 24 weeks after the injections. At the 2, 4, 8, 12, and 24-week times after the injection, rabbits were euthanized, and MRI of the harvested spinal columns was obtained to grade the degeneration. The discs injected with OP-1 or lactose and noninjected discs were subjected to biochemical and histologic analysis. The specimens at the 24-week time were limited to histologic evaluation. RESULTS: The anular puncture with a needle induced a consistent disc narrowing within 4 weeks. The injection of OP-1 induced a restoration of disc height at 6 weeks, which was sustained for the entire experimental period, up to 24 weeks after the injection. The injection of lactose alone did not change the course of disc narrowing over the same time. MRI grading score showed significant differences between the OP-1 and lactose groups at the 8, 12, and 24-week times, suggesting an increase in water content in the nucleus pulposus of the OP-1 group. The proteoglycan content of the nucleus pulposus and anulus fibrosus was significantly higher in the OP-1 group than in the control group. The degeneration grades of the punctured discs in the OP-1 group were significantly lower than those in the lactose group. CONCLUSION: The results of this study show the feasibility of restoring degenerative rabbit discs by a single injection of OP-1 into the nucleus pulposus. Importantly, the effects of the OP-1 injection on disc height were sustained for up to 24 weeks. The metabolic changes in the cells, following a single injection, might be sustained and, thus, induce long-term changes in disc structure. An efficacy study in large animals is required to show further that the intradiscal injection of OP-1, or bone morphogenetic proteins or growth factors with similar properties would be useful for the structural restoration of the IVD in humans.

Animals↗
PubMed2006

The demographics of same-sex marriages in Norway and Sweden.

The present study investigates the demographics of same-sex marriages--that is, registered partnerships-in Norway and Sweden. We give an overview of the demographic characteristics of the spouses of these partnerships, study patterns of their divorce risks, and compare the dynamics of same-sex couples with those of heterosexual marriages. We use longitudinal information from the population registers of the two countries that cover all persons in partnerships. Our demographic analyses include information on characteristics such as age, sex, geographic background, experience of previous opposite-sex marriage, parenthood, and educational attainment of the partners involved. The results show that in many respects, the distributions of married populations on these characteristics differ by the sex composition of the couples. Patterns in divorce risks are rather similar in same-sex and opposite-sex marriages, but divorce-risk levels are considerably higher in same-sex marriages. The divorce riskforfemale partnerships is double that for male partnerships.

Adult↗
PubMed2006

Gendering family composition: sex preferences for children and childbearing behavior in the Nordic countries.

It has been argued that a society's gender system may influence parents' sex preferences for children. If this is true, one should expect to find no evidence of such preferences in countries with a high level of gender equality. In this article, we exploit data from population registers from Denmark, Finland, Norway, and Sweden to examine continuities and changes in parental sex preferences in the Nordic countries during the past three to four decades. First, we do not observe an effect of the sex of the first born child on second-birth risks. Second, we detect a distinct preference for at least one child of each sex among parents of two children. For third births, Danish, Norwegian, and Swedish parents seem to develop a preference for having a daughter, while Finns exhibit a significant preference for having a son. These findings show that modernization and more equal opportunities for women and men do not necessarily lead to parental gender indifference. On the contrary, they may even result in new sex preferences.

Attitude↗
PubMed2005

Labour-market status and first-time parenthood: the experience of immigrant women in Sweden, 1981-97.

This paper investigates the impact of labour-market attachment on first births of foreign-born women in Sweden. The study uses a longitudinal, register-based dataset consisting of the entire population of immigrants from ten nations and a 5-per-cent random sample of natives. The effects of earned income are evident, with increased income levels increasing the probability of becoming a mother for all observed nationalities. The effects of various forms of participation and non-participation in the labour force do not vary greatly between immigrants and the Swedish-born. Among all subgroups, we find a higher propensity to begin childbearing among those who are established in the labour market. Contrary to popular belief, receiving welfare benefits clearly reduces first-birth intensity for immigrants but not for natives. The similarity in patterns across widely different national groups supports the notion that various institutional factors affecting all subgroups are crucial in influencing childbearing behaviour.

Adolescent↗
PubMed2004

Physiological and genetic characterisation of some new Aphanomyces strains isolated from freshwater crayfish.

Five Aphanomyces strains were isolated during suspected outbreaks of crayfish disease in Spain and Italy. Genetic and physiological evidence show that the strains isolated from the freshwater crayfish Procambarus clarkii and Pacifastacus leniusculus, do not fit into any previously identified group of Aphanomyces astaci and are not capable of killing crayfish following standardised experimental infection. RAPD-PCR and ITS sequencing analysis show a high degree of similarity between the new isolates, while they are clearly different from the A. astaci reference strains. They do, however, possess some properties, which are commonly associated with parasitic species such as repeated zoospore emergence and the lack of sexual reproduction. The five isolates share some physiological properties i.e. a high growth rate, and germination in response to nutrients and, in contrast to A. astaci, they do not express chitinase constitutively during growth or sporulation. Until their taxonomic status is fully elucidated we suggest that the new isolates be given the tentative species name Aphanomyces repetans.

Animals↗
PubMed2004

Synthesis and biological evaluation of new 1,2-dihydro-4-hydroxy-2-oxo-3-quinolinecarboxamides for treatment of autoimmune disorders: structure-activity relationship.

Roquinimex-related 3-quinolinecarboxamide derivatives were prepared and evaluated for treatment of autoimmune disorders. The compounds were tested in mice for their inhibitory effects on disease development in the acute experimental autoimmune encephalomyelitis model and selected compounds in the beagle dog for induction of proinflammatory reaction. Structure-activity relationships are discussed. Compound 8c, laquinimod, showed improved potency and superior toxicological profile compared to the lead compound roquinimex (1b, Linomide) and was selected for clinical studies (currently in phase II).

Adjuvants, Immunologic↗
PubMed2003

Spermine prevents cytochrome c release in glucocorticoid-induced apoptosis in mouse thymocytes.

Apoptosis can be induced in primary cultures of mouse thymocytes using the glucocorticoid dexamethasone. Addition of the polyamine spermine simultaneously with dexamethasone reduces the induction of apoptosis compared to treatment with dexamethasone alone. We investigated the signal transduction pathway at the mitochondrial level in order to elucidate spermine's protective effect. Mitochondrial involvement is evident due to the loss of mitochondrial transmembrane potential, release of cytochrome c into the cytosol and activation of caspase-9 in dexamethasone-treated thymocytes. The addition of spermine inhibited the release of cytochrome c from the mitochondria into the cytosol, and also the activation of caspase-9. When the mitogen concanavalin A (Con A) was added to dexamethasone- plus spermine-treated thymocytes, the number of apoptotic cells in the pre-G(1)peak was reduced compared to thymocytes treated with only dexamethasone plus spermine. Comparing concanavalin A added to dexamethasone-treated or to dexamethasone plus spermine-treated thymocytes, showed a markedly reduced pre-G(1)peak in the latter. Thus, the spermine-induced inhibition of cytochrome c release confers a survival advantage on thymocytes.

Animals↗
PubMed2002

Antiferroelectric liquid-crystal mixture without smectic layer shrinkage at the direct Sm-A*-Sm-C(*)(a) transition.

We report results of x-ray, optic, electro-optic, and dielectric investigations on an antiferroelectric liquid-crystal mixture exhibiting a direct second-order phase transition between the Sm-A* and Sm-C(*)(a) phases with virtually no shrinkage in the smectic layer spacing. The birefringence measurements and texture observations suggest that the phase transition follows the diffuse cone model of Adrian de Vries, which explains the constant layer spacing. The antiferroelectric nature of the tilted phase is verified by the presence of twin polarization reversal peaks in the current response and by the absence of strong absorptions in the dielectric spectrum. The threshold for switching this phase to the synclinic, ferroelectric state is sharp and occurs at a very low voltage.

Journal Article↗
PubMedDate not supplied

Meta-analysis of the efficacy and safety of intradiscal electrothermal therapy (IDET).

OBJECTIVE: The objective of this study was to determine the representative outcomes of the intradiscal electrothermal therapy (IDET) procedure in terms of pain relief, reduction of disability, and risk of complications. DESIGN: Meta-analysis, using a random-effects model. A Medline literature search was conducted using search terms associated with the IDET procedure including IDET, intradiscal electrothermal therapy, intervertebral disk, and annuloplasty. OUTCOME MEASURES: The outcomes analyzed were the visual analog scale (VAS) assessment of pain, the bodily pain, and physical functioning subscales of the SF-36 health survey, and the Oswestry disability index. RESULTS: From 1998 to March 2005, 62 peer-reviewed articles were identified regarding the IDET procedure. Forty-five articles were excluded, leaving a total of 17 unique published reports included in this review. The overall mean improvement in pain intensity was 2.9 points as measured by the VAS. The overall mean improvement in physical function was 21.1 points as measured by the SF-36. The overall mean improvement in bodily pain was 18.0 points as measured by the SF-36. The overall mean improvement in disability was 7.0 points as measured by the Oswestry disability index. The overall incidence of complications was 0.8%. CONCLUSION: Although variation exists in the reported outcomes among the various studies of the IDET procedure, the pooled results of the published studies provide compelling evidence of the relative efficacy and safety of the IDET procedure.

Back Pain↗