Biomedical subjects

M Nilsson

Publications and source records attributed to M Nilsson.

At least 73 records · Page 4Linked to original sources

PubMed2001

Use of complementary and alternative medicine remedies in Sweden. A population-based longitudinal study within the northern Sweden MONICA Project. Multinational Monitoring of Trends and Determinants of Cardiovascular Disease.

OBJECTIVES: Previous studies have shown a high prevalence of users of complementary and alternative medicine (CAM) remedies in Anglo-Saxon countries. We have explored the use of CAM remedies in Sweden, its distribution in different population groups and time trends during the years 1990-99. DESIGN AND SUBJECTS: Within the framework of the population-based northern Sweden Multinational Monitoring of Trends and Determinants of Cardiovascular Disease (MONICA) Project, randomly selected 25-74-year-old participants in risk factor surveys performed in 1990, 1994 and 1999 responded to questions about their use of CAM remedies. The participation rate was 72%. RESULTS: Amongst 5794 respondents in the 1999 survey, 30.5% reported that they had taken a CAM product (vitamins, minerals or biological CAM remedy) in the preceding 2 weeks. Vitamins/minerals only had been taken by 11.7% and other CAM remedies (dominated by fish oil, ginseng and Q10) with or without vitamins/minerals by 18.8%. Use of CAM remedies was more frequent in women than in men and more frequent in people with high than with low level of education. The prevalence was unrelated to a history of severe cardiovascular disease or diabetes but significantly more common in subjects with poor self-perceived health, particularly so in women. During 1990-99, the use of CAM remedies increased, more in women than in men. CONCLUSIONS: The prevalence of CAM remedy use (other than vitamins and minerals) is high in Sweden. It has been increasing during the 1990s. Its use is particularly common in women, well-educated people and in those with poor self-perceived health.

Adult↗

PubMed2001

Iodide handling by the thyroid epithelial cell.

Iodination of thyroglobulin, the key event in the synthesis of thyroid hormone, is an extracellular process that takes place inside the thyroid follicles at the apical membrane surface that faces the follicular lumen. The supply of iodide involves two steps of TSH-regulated transport, basolateral uptake and apical efflux, that imprint the polarized phenotype of the thyroid cell. Iodide uptake is generated by the sodium/iodide symporter present in the basolateral plasma membrane. A candidate for the apical iodide-permeating mechanism is pendrin, a chloride/iodide transporting protein recently identified in the apical membrane. In physiological conditions, transepithelial iodide transport occurs without intracellular iodination, despite the presence of large amounts of thyroglobulin and thyroperoxidase inside the cells. The reason is that hydrogen peroxide, serving as electron acceptor in iodide-protein binding and normally produced at the apical cell surface, is rapidly degraded by cytosolic glutathione peroxidase once it enters the cells. Iodinated thyroglobulin in the lumen stores not only thyroid hormone but iodine incorporated in iodotyrosine residues as well. After endocytic uptake and degradation of thyroglobulin, intracellular deiodination provides a mechanism for recycling of iodide to participate in the synthesis of new thyroid hormone at the apical cell surface.

Cell Membrane↗

PubMed2001

Antimicrobial susceptibility patterns of enterococci in intensive care units in Sweden evaluated by different MIC breakpoint systems.

Three hundred and twenty-two (322) clinical isolates were collected from patients admitted to intensive care units (ICUs) at eight Swedish hospitals between December 1996 and December 1998. Of the isolates, 244 (76%) were Enterococcus faecalis, 74 (23%) were Enterococcus faecium and four (1%) were other Enterococcus spp. MICs of ampicillin, imipenem, meropenem, piperacillin/tazobactam, ciprofloxacin, trovafloxacin, clinafloxacin, gentamicin, streptomycin, vancomycin, teicoplanin, quinupristin/dalfopristin, linezolid and evernimicin were determined by Etest. Susceptible and resistant isolates were defined according to the species-related MIC breakpoints of the British Society for Antimicrobial Chemotherapy (BSAC), the National Committee for Clinical Laboratory Standards (NCCLS) and the Swedish Reference Group for Antibiotics (SRGA). Tentative breakpoints were applied for new/experimental antibiotics. Multidrug resistance among enterococci in ICUs is not uncommon in Sweden, particularly among E. faecium, and includes ampicillin resistance and concomitant resistance to fluoroquinolones. Almost 20% of E. faecalis isolates showed high-level resistance to gentamicin and concomitant resistance to fluoroquinolones. Vancomycin-resistant enterococci were only found sporadically. Among the new antimicrobial agents, linezolid and evernimicin showed the best activity against all enterococcal isolates. There was good concordance between the BSAC, NCCLS and SRGA breakpoints in detecting resistance. When applying the SRGA breakpoints for susceptibility, isolates were more frequently interpreted as intermediate. This might indicate earlier detection of emerging resistance using the SRGA breakpoint when the native population is considered susceptible, but with the risk that isolates belonging to the native susceptible population will be incorrectly interpreted as intermediate.

Anti-Bacterial Agents↗

PubMed2001

Comparison of the fibronectin-binding protein FNE from Streptococcus equi subspecies equi with FNZ from S. equi subspecies zooepidemicus reveals a major and conserved difference.

The gene fnz from Streptococcus equi subspecies zooepidemicus encodes a cell surface protein that binds fibronectin (Fn). Fifty tested isolates of S. equi subspecies equi all contain DNA sequences with similarity to fnz. This work describes the cloning and sequencing of a gene, designated fne, with similarity to fnz from two S. equi subspecies equi isolates. The DNA sequences were found to be identical in the two strains, and sequence comparison of the fne and fnz genes revealed only minor differences. However, one base deletion was found in the middle of the fne gene and eight base pairs downstream of the altered reading frame there is a stop codon. An Fn-binding protein was purified from the growth medium of a subspecies equi culture. Determination of the NH(2)-terminal amino acid sequence and molecular mass, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed that the purified protein is the gene product of the 5'-terminal half of fne. Fn-binding activity has earlier only been found in the COOH-terminal half of FNZ. By the use of a purified recombinant protein containing the NH(2) half of FNZ, we provide here evidence that this half of the protein also harbors an Fn-binding domain.

Adhesins, Bacterial↗

PubMed2001

Interactions between monoamines, glutamate, and GABA in schizophrenia: new evidence.

In spite of its proven heuristic value, the dopamine hypothesis of schizophrenia is now yielding to a multifactorial view, in which the other monoamines as well as glutamate and GABA are included, with a focus on neurotransmitter interactions in complex neurocircuits. The primary lesion(s) in schizophrenia does not necessarily involve any of these neurotransmitters directly but could deal with a more general defect, such as a faulty connectivity of developmental origin. Nevertheless, a precise identification of neurotransmitter aberrations in schizophrenia will probably provide clues for a better understanding of the disease and for the development of new treatment and prevention strategies.

Animals↗

PubMed2001

Ansatz for dynamical hierarchies.

Complex, robust functionalities can be generated naturally in at least two ways: by the assembly of structures and by the evolution of structures. This work is concerned with spontaneous formation of structures. We define the notion of dynamical hierarchies in natural systems and show the importance of this particular kind of organization for living systems. We then define a framework that enables us to formulate, investigate, and manipulate such dynamical hierarchies. This framework allows us to simultaneously investigate different levels of description together with their interrelationship, which is necessary to understand the nature of dynamical hierarchies. Our framework is then applied to a concrete and very simple formal, physicochemical, dynamical hierarchy involving water and monomers at level one, polymers and water at level two, and micelles (polymer aggregates) and water at level three. Formulating this system as a simple two-dimensional molecular dynamics (MD) lattice gas allows us within one dynamical system to demonstrate the successive emergence of two higher levels (three levels all together) of robust structures with associated properties. Second, we demonstrate how the framework for dynamical hierarchies can be used for realistic (predictive) physicochemical simulation of molecular self-assembly and self-organization processes. We discuss the detailed process of micellation using the three-dimensional MD lattice gas. Finally, from these examples we can infer principles about formal dynamical hierarchies. We present an ansatz for how to generate robust, higher-order emergent properties in formal dynamical systems that is based on a conjecture of a necessary minimal complexity within the fundamental interacting structures once a particular simulation framework is chosen.

Chemical Phenomena↗

PubMed2001

Defense of the ansatz for dynamical hierarchies.

Gross and McMullin [Artificial Life, 7, 355-365] criticize the conclusions of our article on dynamical hierarchies [Artificial Life, 7, 329-353]. In this note we respond to their criticisms. After clarifying our ansatz, we argue that the simulations presented by Gross and McMullin present no evidence against the ansatz, in part because their simulations use a different simulation framework, and in part because their simulations are no less complex than ours. We also clarify why the micelles in our simulations are third-order emergent structures, and why we emphasize realism in our simulation.

Models, Theoretical↗

PubMed2001

Shifts in B12 opinions in primary health care of Sweden.

AIMS: The diagnosis and management of vitamin B12 deficiency varies between countries and within countries. The aim of the study was to map current attitudes and values behind clinical decision-making in Swedish primary health care, which has a unique B12 tradition: two patients out of three are treated with oral high-dose cyanocobalamin. Most patients with B12-associated problems are managed in primary health care by general practitioners (GPs). METHODS: The study was designed to elucidate possible opinion shifts among GPs during the period 1996-1998. GPs (n=499), stratified and randomized, received a questionnaire with 24 statements on B12-associated clinical and laboratory problems, to be evaluated by a visuo-analogue scale. RESULTS: The majority of GPs in primary health care in Sweden accepted homocysteine and methylmalonic acid (MMA) as markers for functional deficiency of vitamin B12. The evaluation of classical markers of B12 deficiency was wary and balanced. There was a consensus of the need for B12 therapy to risk groups such as patients with atrophic gastritis or previous gastric surgery. The answers also appeared to reflect an improvement of professional knowledge and competence concerning B12-associated problems among Swedish GPs between 1996 and 1998. CONCLUSIONS: The overriding conclusion was that B12-associated opinions of Swedish GPs were stable within the period studied, with marginal improvements of knowledge and competence.

Attitude of Health Personnel↗

PubMed2000

[Acute abdomen calls for considerable care resources. Analysis of 3727 in-patients in the county of Stockholm during the first quarter of 1995].

A total of 3,727 in-patients with acute abdominal symptoms were identified during the first quarter of 1995 at the surgical clinics of the nine hospitals with emergency departments in the county of Stockholm. The diagnoses were: non-specific abdominal pain 24%; cholecystitis 9%; appendicitis 8%; bowel obstruction 7%; intra-abdominal malignancy, diseases of the urinary tract and peptic ulcer 6% each; gastrointestinal hemorrhage, diverticulitis of the colon and pancreatitis 5% each; other diseases as a cause of abdominal symptoms, 19%. 1,601 operations were performed of which 47% were endoscopic procedures. The mean duration of hospital stay was 4.8 days. The length of stay increased significantly with age. The age-related relative frequency of hospitalization due to acute abdominal pain was also dramatically higher in the elderly cohorts. These facts and the prognosis of an 18% increase of inhabitants 50 years of age or older until 2010 in Greater Stockholm signal an increased need of hospital resources for this large group of patients in the coming years.

Abdomen, Acute↗

PubMed2000

Seasonal variation in rates of methane production from peat of various botanical origins: effects of temperature and substrate quality.

The methane produced in peat soils can vary over the growing season due to variations in the supply of available substrate, the activity of the microbial community or changes in temperature. Our aim was to study how these factors regulate the methane production over the season from five different peat types of different botanical origin. Peat samples were collected on seven occasions between June and September. After each sampling, the peat soils were incubated at five different temperatures (7, 10, 15, 20 and 25 degrees C) without added substrate, or at 20 degrees C with added substrate (glucose, or H(2)/CO(2), or starch). Rates of methane production averaged over the season differed significantly (P<0.05, R(2)=0.76) among the five peat types, the minerotrophic lawn producing the highest rates, and the hummock peat producing the lowest. The seasonal average Q(10) values for each plant community varied between 4.6 and 9.2, the highest value being associated with the ombrotrophic lawn and the lowest value with the mud-bottom plant community. For the unamended peat samples, the rates of methane production from each plant community varied significantly (P<0.05) over the season. This implies that the quality of organic matter, in combination with changes in temperature, explains the seasonal variation in methane production. However, addition of saturating amounts of glucose, H(2)/CO(2) or starch at 20 degrees C significantly reduced the seasonal variation (P<0.05) in methane production in peat from the minerotrophic lawn, wet carpet and mud-bottom plant communities. This suggests that substrate supply (e.g. root exudates) for the micro-organisms also varied over the season at these sites. Seasonal variation in methane production rates was apparent in peat from the hummock and ombrotrophic lawn plant communities even after addition of substrates, suggesting that the active biomass of the anaerobic microbial populations at these sites was regulated by other factors than the ones studied.

Journal Article↗

PubMed2000

[The star-shaped cells. Astrocytes are involved in the pathogenesis and progress of neurological diseases].

Recently, knowledge about the role of astrocytes in the brain has increased substantially. As a result we have had to rethink old views regarding how the brain works at the cellular level. Neurons can no longer be regarded as the only cell types of functional significance. The picture instead appears to be far more complex, with an ongoing exchange of information between different cell types, and this interaction is suggested to be particularly important between neurons and astrocytes. Astrocytes express receptors for different classes of neurotransmitters, and have both voltage and receptor operated ion channels. Through active uptake and release of ions, neurotransmitters and water they control the brain interstitium. Intercellular communication via transfer of neuroactive substances through gap junctions makes it possible to coordinate different activities in large areas of the brain. Dysfunction of astrocytic physiology is thought to contribute to the pathogenesis and progress of various neurological disorders such as epilepsy, stroke and cerebral edema.

Astrocytes↗

PubMed2000

Incidence and genetic diversity of group C rotavirus among adults.

Fecal samples from a 1-year prospective study were investigated to establish the role of group C rotavirus infections in acute diarrhea in Swedish adults (>15 years old). Rotaviruses were found in samples from 3% of the patients, and, in 35% of these, group C rotavirus was detected. Clinical symptoms of group C rotavirus infection were generally milder than those of group A rotavirus infection. Gene 8 (vp7) from 12 group C isolates, including strains from the prospective study, a military outbreak, and a sporadic case, was sequenced. The gene was found to be extremely conserved, with identities of 99.1%-100% at the amino acid level. This study has systematically investigated the prevalence and genetic diversity of group C rotavirus in adults. The data confirm the extreme sequence conservation within human group C rotavirus strains and suggest that symptomatic group C rotavirus infections occur more frequently in adults than has been previously recognized.

Adult↗

PubMed2000

Synthesis of a spacer-containing disaccharide fragment of Bordetella pertussis lipopolysaccharide.

The disaccharide 2-(p-aminophenyl)ethyl 4-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-2,3-diacetamido-2 ,3-dideoxy-alpha-D-mannopyranoside uronate, which is assumed to be a partial structure of the Bordetella pertussis polysaccharide, was synthesized starting from D-glucose and D-glucosamine, respectively. The major synthetic transformations were conversion of D-glucosamine into the donor ethyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-1-thio-beta-D-glucopyranoside and conversion of glucose, by a sequence involving 2,3-epoxide formation/opening, nucleophilic triflate displacement in the 3-position, and necessary protecting group manipulations, into the acceptor 2-(p-trifluoroacetamidophenyl)ethyl 6-O-benzyl-2,3-diazido-2,3-dideoxy-alpha-D-mannopyranoside. Coupling of the donor and acceptor units promoted by dimethyl(methylthio)sulfonium triflate followed by selective oxidation of the 6'-position and deprotection gave the target disaccharide.

Bordetella pertussis↗

PubMed2000

PCR-generated padlock probes detect single nucleotide variation in genomic DNA.

Circularizing oligonucleotide probes, so-called padlock probes, have properties that should prove valuable in a wide range of genetic investigations, including in situ analyses, genotyping and measurement of gene expression. However, padlock probes can be difficult to obtain by standard oligonucleotide synthesis because they are relatively long and require intact 5'- and 3'-end sequences to function. We describe a PCR-based protocol for flexible small-scale enzymatic synthesis of such probes. The protocol also offers the advantage over chemical synthesis that longer probes can be made that are densely labeled with detectable functions, resulting in an increased detection signal. The utility of probes synthesized according to this protocol is demonstrated for the analysis of single nucleotide variations in human genomic DNA both in situ and in solution.

Adenosine Triphosphatases↗

PubMed2000

Induction of basal cell carcinomas and trichoepitheliomas in mice overexpressing GLI-1.

Basal cell carcinoma is the most prevalent cancer in the western world, showing a rapid increase in incidence. Activation of the Sonic hedgehog/Patched (PTCH) signaling pathway because of PTCH1 inactivation is a key event in sporadic and familial basal cell carcinoma development in humans and is associated with transcriptional activation of specific target genes, including PTCH1 itself. These changes are analogous to the situation in Drosophila where hedgehog activates the zinc-finger transcription factor Cubitus interruptus, leading to increased transcription of target genes. In the present study, we show that mice ectopically expressing the human Cubitus interruptus homolog GLI-1 in the skin develop tumors closely resembling human BCCs as well as other hair follicle-derived neoplasias, such as trichoepitheliomas, cylindromas, and trichoblastomas. Furthermore, examination of the tumors revealed wild-type p53 and Ha ras genes. These findings firmly establish that increased GLI-1 expression is central and probably sufficient for tumor development and suggest that GLI-1-induced tumor development does not depend on additional p53 or Ha ras mutations.

Animals↗

PubMed2000

Error thresholds for quasispecies on dynamic fitness landscapes.

In this paper we investigate error thresholds on dynamic fitness landscapes. We show that there exists both a lower and an upper threshold, representing limits to the copying fidelity of simple replicators. The lower bound can be expressed as a correction term to the error threshold present on a static landscape. The upper error threshold is a new limit that only exists on dynamic fitness landscapes. We also show that for long genomes and/or highly dynamic fitness landscapes there exists a lower bound on the selection pressure required for the effective selection of genomes with superior fitness independent of mutation rates, i.e. there are distinct nontrivial limits to evolutionary parameters in dynamic environments.

Biological Evolution↗

PubMed2000

Antibody prevalence and specificity to group C rotavirus in Swedish sera.

Of 160 sera collected from different age groups throughout Sweden, 38% were found to be antibody positive for group C rotavirus. The highest antibody prevalence rate was found in individuals aged 11-30 years (45%). An immunoprecipitation assay revealed that the antibodies were directed against VP2, VP4, VP6, VP7, and NSP2, with VP6 being the most immunogenic protein. Neutralising antibodies against a cultivable porcine group C rotavirus (strain AmC-1/Cowden) were detected in 16/19 individuals at titres from 160 to 5,120. The results indicate that group C rotavirus infections are relatively common in older Swedish children and adults but appear to be less common in children younger than 5 years of age. It is concluded that porcine and human group C rotaviruses share epitopes critical for stimulation of neutralising antibodies.

Adolescent↗

PubMed2000

Proteolytic activity in intact sheets of polarized epithelial cells as determined by a cell-permeable fluorogenic substrate.

The purpose of the present investigation was to develop a system for continuous evaluation of extralysosomal proteolytic activity and its regulation in polarized epithelial cells. Filter inserts containing a tight monolayer of primary cultured pig thyrocytes were placed in a thermostated aluminium block. The cell-permeable, fluorogenic calpain and proteasome substrate succinyl-Leu-Leu-Val-Tyr-7-amino-4-methylcoumarin was added to the apical buffer and fluorescence changes were continuously measured via the fibre optics of a luminometer held at a fixed distance from the cell layer. Basal proteolytic activity was reduced by 60-70% by the proteasome inhibitor lactacystin. Proteolysis was increased within a few minutes after application of Ca(2+)-mobilizing agents (ionomycin, 4-bromo-A23187, thapsigargin and maitotoxin). Forskolin and staurosporine also enhanced the proteolytic activity. We conclude that Ca(2+)mobilization, and possibly also changes of protein kinase activity, rapidly increase non-lysosomal proteolysis in the intact thyroid epithelium.

Acetylcysteine↗