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Biomedical subjects

S Marklund

Publications and source records attributed to S Marklund.

At least 19 recordsLinked to original sources
PubMed2003

Fibre composition of human intrinsic tongue muscles.

The muscle fibre composition of three human intrinsic tongue muscles, the longitudinalis, verticalis and transversus, was investigated in four anterior to posterior regions of the tongue using morphological and enzyme- and immunohistochemical techniques. All three muscles typically contained type I, IIA and IM/IIC fibres. Type I fibres expressed slow myosin heavy chain (MyHC), type II fibres fast MyHC, mainly fast A MyHC, whereas type IM/IIC coexpressed slow and fast MyHCs. Type II fibres were in the majority (60%), but regional differences in proportion and diameter of fibre types were obvious. The anterior region of the tongue contained a predominance of relatively small type II fibres (71%), in contrast to the posterior region which instead showed a majority of larger type I and type IM/IIC fibres (66%). In general, the fibre diameter was larger in the posterior region. This muscle fibre composition of the tongue differs from those of limb, orofacial and masticatory muscles, probably reflecting genotypic as well as phenotypic functional specialization in oral function. The predominance of type II fibres and the regional differences in fibre composition, together with intricate muscle structure, suggest generally fast and flexible actions in positioning and shaping the tongue, during vital tasks such as mastication, swallowing, respiration and speech.

Adenosine Triphosphatases↗
PubMed2003

Molecular characterization and mutational screening of the PRKAG3 gene in the horse.

The PRKAG3 gene encodes a muscle-specific isoform of the regulatory gamma subunit of AMP-activated protein kinase (AMPK). A major part of the coding PRKAG3 sequence was isolated from horse muscle cDNA using reverse-transcriptase (RT)-PCR analysis. Horse-specific primers were used to amplify genomic fragments containing 12 exons. Comparative sequence analysis of horse, pig, mouse, human, Fugu, and zebrafish was performed to establish the exon/intron organization of horse PRKAG3 and to study the homology among different isoforms of AMPK gamma genes in vertebrates. The results showed conclusively that the three different isoforms (gamma1, gamma2, and gamma3) were established already in bony fishes. Seven single nucleotide polymorphisms (SNPs), five causing amino acid substitutions, were identified in a screening across horse breeds with widely different phenotypes as regards muscle development and intended performance. The screening of a major part of the PRKAG3 coding sequence in a small case/control material of horses affected with polysaccharide storage myopathy did not reveal any mutation that was exclusively associated with this muscle storage disease. The breed comparison revealed several potentially interesting SNPs. One of these (Pro258Leu) occurs at a residue that is highly conserved among AMPK gamma genes. In an SNP screening, the variant allele was only found in horse breeds that can be classified as heavy (Belgian) or moderately heavy (North Swedish Trotter, Fjord, and Swedish Warmblood) but not in light horse breeds selected for speed or racing performance (Standardbred, Thoroughbred, and Quarter horse) or in ponies (Icelandic horses and Shetland pony). The results will facilitate future studies of the possible functional significance of PRKAG3 polymorphisms in horses.

AMP-Activated Protein Kinases↗
PubMed2002

Melanocortin-4 receptor (MC4R) genotypes have no major effect on fatness in a Large White x Wild Boar intercross.

The melanocortin-4 receptor (MC4R), a G-protein coupled receptor, is implicated in mediating the effect of leptin on food intake and energy balance. A previous candidate gene study reported an association between an MC4R missense mutation (Asp298Asn) and fatness, growth and feed intake in pigs. To assess this association further, we analysed the segregation of this missense mutation in relation to variation in fatness traits using a Wild Boar x Large White intercross. The Wild Boar and Large White founders were homozygous for different MC4R alleles. The MC4R was assigned to the expected region on pig chromosome 1. The statistical evaluation did not reveal any indication of a significant effect on fatness related traits in this pedigree.

Animals↗
PubMed2001

The impact of psychosocial 'markers' on the outcome of rehabilitation.

PURPOSE: The aim of this study was to identify substantial psychosocial events--'psychosocial markers' (PMs) in the clients files and to correlate the PMs to the outcome of the rehabilitation, in order to find out whether this information had any impact on the outcome of vocational rehabilitation (VR). METHOD: Three-hundred and seventy-two individuals were included, being an object of a VR measure during 1993-1994. All were impaired by either disc hernia back pain syndrome or other diseases of the loco-motor system. The PM was defined as any psychosocial loaded information of the person's life situation, not immediately related to the original set of medical problems. RESULTS: Twenty-seven PMs were identified among men and 36 for women. Alcohol related problems dominated for men and private life related problems for women. Only approximately 25% of the PM concerned work related matters. After 3 years the OR (odds ratio) for full disability pension was 2.6 (n.s.) for men with the PM and 4.3 (p < 0.05) for women. The outcome was independent of background factors such as unemployment, blue-collar work and low education. CONCLUSIONS: The PM was found to be an important and independent factor to impact the outcome of rehabilitation in women.

Back Pain↗
PubMed2001

Widespread origins of domestic horse lineages.

Domestication entails control of wild species and is generally regarded as a complex process confined to a restricted area and culture. Previous DNA sequence analyses of several domestic species have suggested only a limited number of origination events. We analyzed mitochondrial DNA (mtDNA) control region sequences of 191 domestic horses and found a high diversity of matrilines. Sequence analysis of equids from archaeological sites and late Pleistocene deposits showed that this diversity was not due to an accelerated mutation rate or an ancient domestication event. Consequently, high mtDNA sequence diversity of horses implies an unprecedented and widespread integration of matrilines and an extensive utilization and taming of wild horses. However, genetic variation at nuclear markers is partitioned among horse breeds and may reflect sex-biased dispersal and breeding.

Alleles↗
PubMed2001

The influence of level and chlorine source on the formation of mono- to octa-chlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls during combustion of an artificial municipal waste.

The formation of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and the three coplanar polychlorinated biphenyls (pPCBs) was studied during labscale fludized bed combustion of eight artificial municipal solid waste (MSW) fuel mixtures. The level of chlorine as well as the chlorine source varies within the different fuel mixtures. Four different chlorine sources were studied, viz, an inorgnaic (NaCl) and three organic sources, pure PVC plastic and two products (floor and cable) and the total chlorine level varies between 0.28% and 1.1%. The experiments were performed in a 5 kW laboratory scale fluidized bed reactor. A correlation between the total chlorine in the fuel and the formation of the hepta- and octa-chlorinated PCDD/F homologues was found. However, the most important variable for changes in the PCDDs/Fs and pPCBs formation was disturbance in the combustion condition and not the variation in chlorine content of the fuel. Furthermore, no differences in formation between the chlorine sources could be seen.

Air Pollutants↗
PubMed2001

Co-combustion of shredder residues and municipal solid waste in a Swedish municipal solid waste incinerator.

Incinerating automotive shredder residue (ASR) in order to increase the recovery from end of life vehicles (ELVs) is an attractive option when recycling this material. In this study, incineration combined with energy recovery, was investigated. The incineration experiments, where 20% shredder residue (SR) was burnt with conventional municipal solid waste (MSW), were conducted in a full-scale MSW horizontal grate incinerator. Measurements were made before, during and after the incineration. The results showed some minor increases in the emission levels of raw gases sampled after an electrostatic filter, but almost no significant differences when sampled after a wet scrubber. An increased level of 'non-toxic' metals was detected within the bottom ash. It was concluded that refined SR, in small quantities, is suitable to add to MSW.

Air Pollutants↗
PubMed2000

The effect of oils on PAH, PCDD, PCDF, and PCB emissions from a spark engine fueled with leaded gasoline.

The effect of synthetic and mineral oils on the formation of polyaromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) in emissions from a spark ignition engine was studied on a Skoda Favorit engine fueled with leaded gasoline. The test cycle simulated urban traffic conditions on a chassis dynamometer, in accordance with the ECC 83.00 test. The data for selected PAHs as well as PCDDs, PCDFs, and PCBs congener profiles are presented. PCDD/Fs emissions for an unused oil and the oil after 10000-km operation varied from 300 to 2000 fmol/m3, PCBs emissions from 75 to 178 pmol/m3, and PAHs emissions from 150 to 420 microg/m3. The content of PCBs in oils varied from 2 to 920 mg/kg.

Benzofurans↗
PubMed2000

Superoxide dismutase and glutathione peroxidase function in progressive myoclonus epilepsies.

Progressive myoclonic epilepsies (EPM) are difficult to treat and refractory to most antiepileptic drugs. Besides epilepsy, EPMs also involve continuous neurological deterioration. Oxidative stress is thought to be an important factor in this process. We therefore analyzed a series of antioxidant enzymes in the blood of patients and compared with healthy age matched controls. In addition patients were given high doses of N-acetylcysteine (NAC), a glutathione percursor to determine if symptoms of EPM would improve. Five patients, four with EPM 1 (Unverricht-Lundborg disease) and one patient with EPM2 (Lafora body disease) were treated with 6 g/day of NAC. Before treatment, plasma samples were analyzed for glutathione peroxidase activity, catalase activity, extracellular superoxide dismutase (SOD) and CuZn-SOD and compared with the controls. Erythrocyte CuZn-SOD was significantly lower in the EPM patients compared to controls. NAC improved markedly and stabilized the neurological symptoms in patients with EPM 1 but had a doubtful effect in the patient with EPM 2.

Acetylcysteine↗
PubMed2000

Mapping of the CYP1A1, SSTR1 and TTF1 genes to pig chromosome 7q refines the porcine-human comparative map.

The cytochrome P-450, subfamily I, polypeptide 1 (CYP1A1), somatostatin receptor 1 (SSTR1) and transcription termination factor 1 (TTF1) genes, predicted to reside on SSC7q based on chromosome painting studies, were selected for genetic mapping in the pig. Porcine sequence tagged sites (STSs) spanning 0.9-1.5 kb genomic DNA sequences were generated and all genes were physically assigned to SSC7q12-q23, q26 using a pig-rodent somatic cell hybrid panel. Direct sequencing of PCR products from four different breeds revealed single nucleotide polymorphisms (SNPs) in all genes. SNPs in the SSTR1 and CYP1A1 genes allowed simple genotyping using PCR-restriction fragment length polymorphism (RFLP) analysis and linkage mapping with the PiGMaP reference families. SSTR1 was found to be closely linked to CYP1A1 (0.0 cM; LOD = 11.1) and ANPEP (0.0 cM; LOD = 9.0). This refined the localization of a previously identified breakpoint in the linkage map between regions with orthology to human chromosome 15q (represented by CYP1A1 and ANPEP) and 14q (represented by SSTR1). Moreover, multipoint linkage data suggest inverted segments of orthology between HSA14q11-q13 and SSC7q. The TTF1 SNP was confirmed by allele-specific PCR but was not informative in any of the families used for linkage analysis.

Animals↗
PubMed2000

A century of controversy regarding the benefit or detriment of occlusal contacts on the mediotrusive side.

Many opinions have been presented in the literature during the past century regarding so-called mediotrusive/balancing/non-working side contacts. During the first half of this century, most authors advocated the advantage of these contacts (it was more or less the state of the art in prosthetic treatments), while during the last 50 years mediotrusive side contacts/interferences have mostly been regarded as a disturbing factor in the functioning of the mandible. Recently, it has been proposed that mediotrusive side contacts have a protective effect on the temporomandibular joint (TMJ). The aim of this study was to review opinions advocated during the twentieth century regarding the advantages and disadvantages of having contacts on the mediotrusive side during lateral excursions of the mandible. We conclude that, at present, there is no uniform body of scientific evidence supporting a balanced occlusion in favour of a mutually protective occlusion or vice versa. Longitudinal studies based on cohorts with different types of occlusal contacts, estimating the risk among these of developing signs and symptoms of temporomandibular disorders, are generally lacking and could provide valuable knowledge in this field.

Bruxism↗
PubMed1999

A missense mutation in the beta-2 integrin gene (ITGB2) causes canine leukocyte adhesion deficiency.

Canine leukocyte adhesion deficiency (CLAD) is a fatal immunodeficiency disease found in Irish setters. The clinical manifestations of CLAD are very similar to LAD in humans and BLAD in cattle, which are both caused by mutations in ITGB2 encoding the leukocyte integrin beta-2 subunit (CD18). Sequence analysis of the ITGB2 coding sequence from a CLAD dog and a healthy control revealed a single missense mutation, Cys36Ser. This cysteine residue is conserved among all beta integrins, and the mutation most likely disrupts a disulfide bond. The mutation showed a complete association with CLAD in Irish setters and was not found in a sample of dogs from other breeds. The causative nature of this mutation was confirmed by transduction experiments using retroviral vectors and human LAD EBV B-cells. The normal canine CD18 formed heterodimers with the human CD11 subunit, whereas gene transfer of the mutant CD18 resulted in very low levels of CD11/CD18 expression. The identification of the causative mutation for CLAD now makes it possible to identify carrier animals with a simple diagnostic DNA test, and it forms the basis for using CLAD as a large animal model for the development and evaluation of clinical treatments for human LAD.

Amino Acid Sequence↗
PubMed1999

Binding of xanthine oxidase to vascular endothelium. Kinetic characterization and oxidative impairment of nitric oxide-dependent signaling.

Concentrations of up to 1.5 milliunits/ml xanthine oxidase (XO) (1.1 micrograms/ml) are found circulating in plasma during diverse inflammatory events. The saturable, high affinity binding of extracellular XO to vascular endothelium and the effects of cell binding on both XO catalytic activity and differentiated vascular cell function are reported herein. Xanthine oxidase purified from bovine cream bound specifically and with high affinity (Kd = 6 nM) at 4 degreesC to bovine aortic endothelial cells, increasing cell XO specific activity up to 10-fold. Xanthine oxidase-cell binding was not inhibited by serum or albumin and was partially inhibited by the addition of heparin. Pretreatment of endothelial cells with chondroitinase, but not heparinase or heparitinase, diminished endothelial binding by approximately 50%, suggesting association with chondroitin sulfate proteoglycans. Analysis of rates of superoxide production by soluble and cell-bound XO revealed that endothelial binding did not alter the percentage of univalent reduction of oxygen to superoxide. Comparison of the extent of CuZn-SOD inhibition of native and succinoylated cytochrome c reduction by cell-bound XO indicated that XO-dependent superoxide production was occurring in a cell compartment inaccessible to CuZn-SOD. This was further supported by the observation of a shift of exogenously added XO from extracellular binding sites to intracellular compartments, as indicated by both protease-reversible cell binding and immunocytochemical localization studies. Endothelium-bound XO also inhibited nitric oxide-dependent cGMP production by smooth muscle cell co-cultures in an SOD-resistant manner. This data supports the concept that circulating XO can bind to vascular cells, impairing cell function via oxidative mechanisms, and explains how vascular XO activity diminishes vasodilatory responses to acetylcholine in hypercholesterolemic rabbits and atherosclerotic humans. The ubiquity of cell-XO binding and endocytosis as a fundamental mechanism of oxidative tissue injury is also affirmed by the significant extent of XO binding to human vascular endothelial cells, rat lung type 2 alveolar epthelial cells, and fibroblasts.

Animals↗
PubMed1999

Close association between sequence polymorphism in the KIT gene and the roan coat color in horses.

The roan coat color in horses is controlled by a dominant allele that is lethal in the homozygous condition. Phenotypic similarities to some pigmentation disorders in human and mouse, combined with comparative mapping data, identified KIT, encoding the mast cell growth factor receptor, as a major candidate gene for the roan locus (Rn). Rn has previously been mapped to equine linkage group (LG) II. In this study, LGII was expanded with KIT and PDGFRA (platelet-derived growth factor receptor alpha) by use of RFLP and linkage analysis. Moreover, highly significant linkage disequilibrium between Rn and a KIT TaqI RFLP, representing a synonymous substitution in exon 19, was revealed. There was a strong KIT-Rn association in most breeds. Almost the complete KIT-encoding sequence was determined by sequence analysis of RT-PCR products. Comparison of horse KIT cDNA sequences, representing three different alleles (two different rn and one Rn), revealed five sequence polymorphisms and several mRNA splice variants, but none of these proved to be specifically associated with Rn. An insertion of a partial (79 bp) LINE1-element between exons 1 and 2, leading to a frameshift, represented about 30% of KIT transcripts in the Belgian roan horse used for the sequence analysis. However, an association between this L1 splice insertion and the roan phenotype was not verified when testing additional unrelated roan and non-roan horses from different breeds. The study strengthens the hypothesis that the roan coat color is controlled by KIT, but further analyses are needed to reveal the causative mutation(s).

Alternative Splicing↗
PubMed1999

New insights into porcine-human synteny conservation.

Eleven genes were mapped to the porcine genome with the aim of improving the human-porcine comparative gene map. Five of these genes were from regions of the human genome painted by porcine chromosomal probes; of these, two mapped to chromosomes not expected from the painting results. Among the six genes from human regions not painted by porcine chromosomal probes, three genes did not map where expected by the principle of parsimony. Several of the gene assignments indicate the existence of small regions of conserved synteny not detected by heterologous chromosome painting, especially in telomeric regions. We have also detected new rearrangements in gene order within the regions of correspondence between human Chromosome (HSA) 15 and porcine Chromosome (SSC) 1 as well as between HSA4 and SSC8.

Animals↗