Biomedical subjects

Jan Karlsson

Publications and source records attributed to Jan Karlsson.

16 recordsLinked to original sources

PubMed2006

Gender and age differences in the relative burden of rhinitis and asthma on health-related quality of life--a Swedish population study.

The aim of this study was to investigate the relative burden of rhinitis and asthma on health-related quality of life (HRQL) as a function of gender and age in the general population. A cross-sectional, general population survey was conducted, comprising 5918 men and women aged 16-64 years. The SF-36 Health Survey was administered by mail, along with questions regarding nasal complaints after 15 years of age and physician-diagnosed asthma. Overall, rhinitis and asthma were each associated with impaired HRQL compared with non-cases and the burden of these illnesses in combination was incremental. In the age group 16-49 years, men and women with rhinitis alone had significantly worse health profiles on most scales than non-cases, while asthmatics, with or without rhinitis, showed further decrements on only a few scales. In the age group 50-64 years, men with rhinitis did not differ from non-cases and no differences were found between asthmatics and rhinitis victims on any scale. In contrast, women aged 50-64 years with rhinitis had significantly worse scores than non-cases on bodily pain and general well-being scales (GH, VT), and asthmatics scored much lower on all scales than those with rhinitis alone. The negative association of rhinitis and asthma with HRQL differs by age and sex in the general population. Women aged 50-64 years with one or both ailments are particularly affected. Such gender and age differences should be taken into consideration in the care and treatment of patients with rhinitis and asthma.

Adolescent↗

PubMed2006

UPSC-BASE--Populus transcriptomics online.

The increasing accessibility and use of microarrays in transcriptomics has accentuated the need for purpose-designed storage and analysis tools. Here we present UPSC-BASE, a database for analysis and storage of Populus DNA microarray data. A microarray analysis pipeline has also been established to allow consistent and efficient analysis (from small to large scale) of samples in various experimental designs. A range of optimized experimental protocols is provided for each step in generating the data. Within UPSC-BASE, researchers can perform standard and advanced microarray analysis procedures in a user-friendly environment. Background corrections, normalizations, quality-control tools, visualizations, hypothesis tests and export tools are provided without requirements for expert-level knowledge. Although the database has been developed primarily for handling Populus DNA microarrays, most of the tools are generic and can be used for other types of microarray. UPSC-BASE is also a repository of Populus microarray information, providing data from 21 experiments on a total of 407 microarray hybridizations in the public domain of the database. There are also an additional 10 experiments containing 347 hybridizations, where the automatically analysed data are searchable.

Databases, Genetic↗

PubMed2006

Bacterioplankton growth and nutrient use efficiencies under variable organic carbon and inorganic phosphorus ratios.

We carried out enclosure experiments in an unproductive lake in northern Sweden and studied the effects of enrichment with different dissolved organic carbon (glucose)/inorganic phosphorous (DOC/Pi) ratios on bacterioplankton production (BP), growth efficiency (BGE), nutrient use efficiency (BNUE), growth rate, and specific respiration. We found considerable variation in BP, BGE, and BNUE along the tested DOC/Pi gradient. BGE varied between 0.87 and 0.24, with the highest values at low DOC/Pi ratios. BNUE varied between 40 and 9 g C g P(-1), with high values at high DOC/Pi ratios. More DOC was thus allocated to growth when bacteria tended to be C-limited, and to respiration when bacteria were P-limited. Specific respiration was positively correlated with bacterial growth rate throughout the gradient. It is therefore possible that respiration was used to support growth in P-limited bacteria. The results indicated that BP can be limited by Pi when BNUE is at its maximum, by organic C when BGE is at its maximum, and by dual organic C and Pi limitation when BNUE and BGE have suboptimal values.

Bacteria↗

PubMed2006

Is restrained eating a risk factor for weight gain in a general population?

BACKGROUND: In modern societies characterized by abundant and accessible foods, restrained eating may become an adaptive behavior to limit weight gain. OBJECTIVE: We assessed the relations between eating behavior (EB) and adiposity in a general population over a 2-y period. DESIGN: We recruited 466 adults and 271 adolescents in 1999 on a geographical basis to participate in a longitudinal study. At the initial examination and 2 y later, they answered an EB questionnaire, the Three-Factor Eating Questionnaire-R18, which measured cognitive restraint (CR), uncontrolled eating, and emotional eating. On the same occasions, several measures of adiposity were also obtained: body mass index (BMI; in kg/m2), waist circumference, the sum of 4 skinfold thicknesses, and percentage body fat. Relations between EB and adiposity were tested separately in adults and adolescents by using mixed linear regressions after adjustment for age, sex, and (in adolescents) Tanner pubertal stage. RESULTS: At baseline, CR was positively associated with BMI in normal-weight subjects (mean BMI: 21.4 in the lowest to 23.3 in the highest CR quintile; P < 0.001) but not in overweight adults (P = 0.25). Initial CR did not predict change in adiposity variables (BMI change: P = 0.79 in adults, P = 0.57 in adolescents and young adults). Conversely, a high initial BMI was associated with a larger increase in CR (beta = 20.1, P < 0.0001 in adults; beta = 21.7, P = 0.003 in adolescents and young adults). CONCLUSIONS: Restrained eating is strongly associated with adiposity in normal-weight subjects but not in overweight subjects. However, restrained eating does not promote weight gain.

Adipose Tissue↗

PubMed2005

Evidence for a protein transported through the secretory pathway en route to the higher plant chloroplast.

In contrast to animal and fungal cells, green plant cells contain one or multiple chloroplasts, the organelle(s) in which photosynthetic reactions take place. Chloroplasts are believed to have originated from an endosymbiotic event and contain DNA that codes for some of their proteins. Most chloroplast proteins are encoded by the nuclear genome and imported with the help of sorting signals that are intrinsic parts of the polypeptides. Here, we show that a chloroplast-located protein in higher plants takes an alternative route through the secretory pathway, and becomes N-glycosylated before entering the chloroplast.

Arabidopsis↗

PubMed2005

The C subunit of Ideonella dechloratans chlorate reductase: expression, purification, refolding, and heme reconstitution.

The C subunit of Ideonella dechloratans chlorate reductase has been expressed in Escherichia coli as a GST fusion protein. Purification from inclusion bodies, followed by refolding and reconstitution with heme, produced a protein with a heme/protein ratio of 0.4, and with UV-vis spectral characteristics similar to those of native chlorate reductase. Wavelength maxima for the alpha and beta bands in the reduced state were 559 and 529 nm for both native chlorate reductase and the reconstituted recombinant subunit, whereas the reduced Soret bands were found at 426 and 424 nm, respectively. These results support the notion of the C subunit as the cytochrome b moiety of I. dechloratans chlorate reductase. Moreover, the availability of a recombinant version of the C subunit is expected to facilitate further studies of electron transfer and protein interaction included in the reaction catalyzed by chlorate reductase.

Bacterial Proteins↗

PubMed2005

Genetic and environmental influences on eating behavior: the Swedish Young Male Twins Study.

BACKGROUND: Eating behavior may be implicated in the increasing prevalence of overweight and obesity, presumably in relation to easy access to energy-dense and highly palatable foods. OBJECTIVE: The aim of the present study was to disentangle genetic and environmental influences on eating behavior in a population-based cohort of male twins. DESIGN: The study included 326 dizygotic and 456 monozygotic male twin pairs aged 23-29 y from Sweden. The revised 21-item version of the Three-Factor Eating Questionnaire (TFEQ-R21) was used to assess eating behavior. This validated instrument consists of 3 dimensions: cognitive restraint, emotional eating, and uncontrolled eating. Structural equation modeling was used to estimate the heritability of eating behavior. RESULTS: Cognitive restraint was the only TFEQ-R21 scale that significantly correlated with BMI (r = 0.39, P < 0.0001). The best-fitted models gave a heritability of 59% (95% CI: 52%, 66%) for cognitive restraint, 60% (95% CI: 52%, 67%) for emotional eating, and 45% (95% CI: 36%, 53%) for uncontrolled eating. CONCLUSIONS: These results show the great importance of genetic factors in the eating behavior of a large, unselected population of young adult male twins. Nonshared environmental factors were also important, whereas shared environmental factors did not contribute to eating behavior.

Adult↗

PubMed2004

A Populus EST resource for plant functional genomics.

Trees present a life form of paramount importance for terrestrial ecosystems and human societies because of their ecological structure and physiological function and provision of energy and industrial materials. The genus Populus is the internationally accepted model for molecular tree biology. We have analyzed 102,019 Populus ESTs that clustered into 11,885 clusters and 12,759 singletons. We also provide >4,000 assembled full clone sequences to serve as a basis for the upcoming annotation of the Populus genome sequence. A public web-based EST database (POPULUSDB) provides digital expression profiles for 18 tissues that comprise the majority of differentiated organs. The coding content of Populus and Arabidopsis genomes shows very high similarity, indicating that differences between these annual and perennial angiosperm life forms result primarily from differences in gene regulation. The high similarity between Populus and Arabidopsis will allow studies of Populus to directly benefit from the detailed functional genomic information generated for Arabidopsis, enabling detailed insights into tree development and adaptation. These data will also valuable for functional genomic efforts in Arabidopsis.

Ecosystem↗

PubMed2004

A transcriptional timetable of autumn senescence.

BACKGROUND: We have developed genomic tools to allow the genus Populus (aspens and cottonwoods) to be exploited as a full-featured model for investigating fundamental aspects of tree biology. We have undertaken large-scale expressed sequence tag (EST) sequencing programs and created Populus microarrays with significant gene coverage. One of the important aspects of plant biology that cannot be studied in annual plants is the gene activity involved in the induction of autumn leaf senescence. RESULTS: On the basis of 36,354 Populus ESTs, obtained from seven cDNA libraries, we have created a DNA microarray consisting of 13,490 clones, spotted in duplicate. Of these clones, 12,376 (92%) were confirmed by resequencing and all sequences were annotated and functionally classified. Here we have used the microarray to study transcript abundance in leaves of a free-growing aspen tree (Populus tremula) in northern Sweden during natural autumn senescence. Of the 13,490 spotted clones, 3,792 represented genes with significant expression in all leaf samples from the seven studied dates. CONCLUSIONS: We observed a major shift in gene expression, coinciding with massive chlorophyll degradation, that reflected a shift from photosynthetic competence to energy generation by mitochondrial respiration, oxidation of fatty acids and nutrient mobilization. Autumn senescence had much in common with senescence in annual plants; for example many proteases were induced. We also found evidence for increased transcriptional activity before the appearance of visible signs of senescence, presumably preparing the leaf for degradation of its components.

Aging↗

PubMed2004

Performance of the Swedish SF-36 version 2.0.

OBJECTIVES: To evaluate the performance of the first non-English (Swedish) SF-36 version 2.0 (V2) regarding scaling assumptions, reliability and validity, with special emphasis on the effects of extending the response scales of the two role functioning scales, role physical (RP) and role emotional (RE), from a dichotomous to a five-step format. METHODS: Questionnaires were mailed to a non-stratified, random national sample of 3000 18-75 year old Swedish residents in 1998-1999. Methods traditionally used in evaluating the original US SF-36 version 1.0 (V1) and other international versions were applied. RESULTS: A total of 73% of the questionnaires were returned. Scaling assumptions were satisfactorily met and generally enhanced compared with V1, particularly regarding the role functioning scales. Floor/ceiling effects were reduced and reliability estimates increased for the role scales. The factor structure was replicated and the relative validity of the role scales as measures of their components increased. Overall, the tests of the criterion-based validity using known groups comparisons produced results supporting hypotheses: scales from the physical domain distinguished best between groups expected to differ in physical health; and scales comprising the mental domain distinguished best between groups expected to differ in mental health. Furthermore, hypothesized differences in mean scale scores as a function of age and social risk factors were confirmed. CONCLUSIONS: The changes to the response formats of the role functioning scales have improved their precision, reliability and validity without jeopardizing the underlying structure of the original SF-36. These changes will likely further enhance the responsiveness of the SF-36.

Activities of Daily Living↗

PubMed2004

The Three-Factor Eating Questionnaire-R18 is able to distinguish among different eating patterns in a general population.

A revised version of the Three-Factor Eating Questionnaire (TFEQ) was developed in an obese population, but its applicability to the general population was not assessed. We aimed to define the relationship between eating behavior and reported food intake. This was a cross-sectional study of 529 middle-aged adults and 358 teenagers and young adults recruited on a geographical basis. The TFEQ-R18 measures 3 aspects of eating behavior: cognitive restraint (CR), uncontrolled eating (UE), and emotional eating. Reported food intake was calculated from a food frequency questionnaire. Girls who scored higher on restrained eating had a lower energy intake than the other girls (9164 kJ vs. 13,163 kJ, P < 0.001). In adult men, energy intake increased with UE (9663 kJ vs. 11,029 kJ in the lower and higher UE tertiles, respectively, P < 0.05). When specific food groups were analyzed, higher CR was positively associated in adults with healthy food groups like green vegetables [OR = 1.92 (0.68-2.44)] and negatively associated with French fries [OR = 0.35 (0.22-0.57)] and sugar [OR = 0.38 (0.23-0.61)]. Energy-dense foods, such as fat, were positively associated with UE [OR = 2.28 (1.46-3.57) for dietary fat]. Finally, emotional eaters had a higher snacking food intake. In teenagers and young adults, most associations were seen with CR. Converse to observations in adults, teenagers and young adults who exhibited a high cognitive restraint reported consumption of fewer energy-dense foods rather than more "healthy foods." The TFEQ-R18 was therefore able to distinguish among different eating patterns in our sample of a French general population.

Adolescent↗

PubMed2003

Proteasome activity in human lens nuclei and correlation with age, gender and severity of cataract.

PURPOSE: The aim of this study was to measure proteasome activity in human lens nuclei resulting from cataract surgery and in different regions of donor lenses. METHODS: The chymotrypsin-like, the trypsin-like and the peptidylglutamyl-peptide hydrolysing activities of the proteasome were studied using synthetic flourogenic substrates. RESULTS: Proteasome activity did not show any correlation with age of the patients or with gender. Increased opacification of the lens nucleus, as estimated prior to surgery using a 4-grade scale, was significantly correlated with decreased activity of all peptidase activities in the insoluble fraction. In the donor lenses, all peptidase activities were highest in the epithelium and decreased rapidly towards the nucleus. CONCLUSIONS: The present study demonstrates that proteasome activity is preserved in the nucleus of lenses from elderly individuals, although a decrease can be seen with cataract formation. This finding may be of importance for elucidating the mechanism behind the formation of nuclear cataract.

Aging↗

PubMed2003

Gene expression in autumn leaves.

Two cDNA libraries were prepared, one from leaves of a field-grown aspen (Populus tremula) tree, harvested just before any visible sign of leaf senescence in the autumn, and one from young but fully expanded leaves of greenhouse-grown aspen (Populus tremula x tremuloides). Expressed sequence tags (ESTs; 5,128 and 4,841, respectively) were obtained from the two libraries. A semiautomatic method of annotation and functional classification of the ESTs, according to a modified Munich Institute of Protein Sequences classification scheme, was developed, utilizing information from three different databases. The patterns of gene expression in the two libraries were strikingly different. In the autumn leaf library, ESTs encoding metallothionein, early light-inducible proteins, and cysteine proteases were most abundant. Clones encoding other proteases and proteins involved in respiration and breakdown of lipids and pigments, as well as stress-related genes, were also well represented. We identified homologs to many known senescence-associated genes, as well as seven different genes encoding cysteine proteases, two encoding aspartic proteases, five encoding metallothioneins, and 35 additional genes that were up-regulated in autumn leaves. We also indirectly estimated the rate of plastid protein synthesis in the autumn leaves to be less that 10% of that in young leaves.

Arabidopsis Proteins↗

PubMed2003

A gene cluster for chlorate metabolism in Ideonella dechloratans.

Chlorate reductase has been isolated from the chlorate-respiring bacterium Ideonella dechloratans, and the genes encoding the enzyme have been sequenced. The enzyme is composed of three different subunits and contains molybdopterin, iron, probably in iron-sulfur clusters, and heme b. The genes (clr) encoding chlorate reductase are arranged as clrABDC, where clrA, clrB, and clrC encode the subunits and clrD encodes a specific chaperone. Judging from the subunit composition, cofactor content, and sequence comparisons, chlorate reductase belongs to class II of the dimethyl sulfoxide reductase family. The clr genes are preceded by a novel insertion sequence (transposase gene surrounded by inverted repeats), denoted ISIde1. Further upstream, we find the previously characterized gene for chlorite dismutase (cld), oriented in the opposite direction. Chlorate metabolism in I. dechloratans starts with the reduction of chlorate, which is followed by the decomposition of the resulting chlorite to chloride and molecular oxygen. The present work reveals that the genes encoding the enzymes catalyzing both these reactions are in close proximity.

Amino Acid Sequence↗

PubMed2002

Cloning, characterisation, and expression of a novel gene encoding chlorite dismutase from Ideonella dechloratans.

The gene for chlorite dismutase was isolated from a lambda ZAP genomic library of Ideonella dechloratans using peptide sequences obtained from the purified protein. A nucleotide sequence of 1200 bp was determined. The chlorite dismutase gene codes for a 285-residue polypeptide, with the experimentally determined N-terminus of the mature protein at residue 38. The N-terminal part of the encoded peptide has the characteristics of a signal sequence for periplasmic proteins. The nucleotide sequence and deduced protein showed no homology to sequences found in the databases. The transcriptional start point of the chlorite dismutase gene was determined with a new primer extension technique using capillary electrophoresis. Expression of recombinant chlorite dismutase in E. coli resulted in an active enzyme with similar spectral properties as the native enzyme.

Amino Acid Sequence↗

PubMedDate not supplied

Coping and distress: what happens after intervention? A 2-year follow-up from the Swedish Obese Subjects (SOS) study.

OBJECTIVE: The study examined effects of weight change on coping and distress in severely obese subjects treated conventionally or undergoing weight reduction surgery. METHODS: We used the Obesity Coping (OC) scale measuring emotion-focused, maladaptive coping (Wishful Thinking) and problem-focused, adaptive coping (Social Trust and Fighting Spirit). We also used the Obesity Distress (OD) scale (Intrusion and Helplessness) and the Hospital Anxiety and Depression (HAD) scale. A total of 1146 surgical candidates and 1085 conventionally treated patients completed the OC and OD before treatment and after 24 months. RESULTS: Weight gainers reduced their use of both problem- and emotion-focused coping, thus leaving distress levels unchanged. All participants who lost weight decreased in emotion-focused coping and distress. Participants losing 20 kg or more also increased in problem-focused coping, resulting in even greater improvements regarding distress. CONCLUSIONS: Two years after starting treatment, the pattern and magnitude of change in coping and distress was the same irrespective of type of treatment and was, instead, related to the amount of weight change (the more weight change the greater the changes in coping and distress). Increases in problem-focused coping required major weight reduction, whereas minor weight gain led to a decrease. Emotion-focused coping decreased irrespective of direction of weight change, suggesting a general intervention effect of receiving professional help and support. These results have implications concerning behavior-based interventions of obese patients.

Adaptation, Psychological↗