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Biomedical subjects

M Sjöström

Publications and source records attributed to M Sjöström.

At least 19 recordsLinked to original sources
PubMed2006

Protein expression in experimental malignant glioma varies over time and is altered by radiotherapy treatment.

Radiotherapy is one of the mainstays of glioblastoma (GBM) treatment. This study aims to investigate and characterise differences in protein expression patterns in brain tumour tissue following radiotherapy, in order to gain a more detailed understanding of the biological effects. Rat BT4C glioma cells were implanted into the brain of two groups of 12 BDIX-rats. One group received radiotherapy (12 Gy single fraction). Protein expression in normal and tumour brain tissue, collected at four different time points after irradiation, were analysed using surface enhanced laser desorption/ionisation - time of flight - mass spectrometry (SELDI-TOF-MS). Mass spectrometric data were analysed by principal component analysis (PCA) and partial least squares (PLS). Using these multivariate projection methods we detected differences between tumours and normal tissue, radiation treatment-induced changes and temporal effects. 77 peaks whose intensity significantly changed after radiotherapy were discovered. The prompt changes in the protein expression following irradiation might help elucidate biological events induced by radiation. The combination of SELDI-TOF-MS with PCA and PLS seems to be well suited for studying these changes. In a further perspective these findings may prove to be useful in the development of new GBM treatment approaches.

Animals↗
PubMed2006

Understanding and preventing childhood obesity and related disorders--IDEFICS: a European multilevel epidemiological approach.

The environment of children has drastically changed in Europe during the last decades as reflected in unhealthy dietary habits and sedentary lifestyle. Nutrition obviously plays a part in the development of overweight in childhood. However, dietary factors and physical activity are also involved in the development of metabolic syndrome, type II diabetes, cardiovascular diseases, osteoporosis, and postural deformities like scoliosis, effects related in part to excessive weight gain. To stop the resulting epidemic of diet- and lifestyle-induced morbidity, efficient evidence-based approaches are needed. These issues are the focus of IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants), a five-year project proposed under the sixth EU framework. The IDEFICS consortium comprises 25 research centres and SMEs across Europe. The planned prospective study will identify risk profile inventories for children susceptible to any of these disorders with emphasis on obesity and its co-morbid conditions. Genetic and non-genetic factors, psychosocial factors and social settings will be considered. The project will devise tailored prevention strategies that are effective, easy to implement and that account for the needs of different social groups. Population-based studies will investigate the impact of sensory perception and provide results concerning internal and external triggers of food choices and children's consumer behaviour. The ethical implications of a "right not to know" of genetic factors will be addressed. We will propose knowledge-based guidelines on dietary and lifestyle activities for health promotion and disease prevention in children for health professionals, stakeholders and consumers.

Adolescent↗
PubMed2006

Multivariate evaluation of VOCs in buildings where people with non-specific building-related symptoms perceive health problems and in buildings where they do not.

UNLABELLED: Volatile organic compounds (VOCs) were sampled in buildings where people with non-specific building-related symptoms perceive health problems and in buildings where they do not. In total, nine persons and 34 buildings were included in the study. The obtained VOC data was evaluated using multivariate methods, to investigate possible systematic differences in air quality of 'problem' and 'non-problem' buildings. All individual compounds were included as variables in a multivariate partial least squares (PLS) data analysis. 'Problem' and 'non-problem' buildings separated into two distinct groups, showing that air samples of the two groups of building were chemically different. PRACTICAL IMPLICATIONS: The study showed that there was an identifiable systematic difference in the collected VOC data between buildings causing and not causing problems for people with non-specific building-related symptoms (also called sick building syndrome, SBS). This is an important indication that even such volatile organic compounds that can be sampled by commonly used adsorbents are of importance for the presence of such symptoms. By coordination of procedures for sampling and analysis of VOCs in buildings between laboratories, to get large datasets and more general models, the method can become a useful diagnostic measure in evaluating indoor air and to identify chemical compounds and sources that contribute to SBS problems.

Environmental Exposure↗
PubMed2005

Microsomal glutathione S-transferases: selective up-regulation of leukotriene C4 synthase during lipopolysaccharide-induced pyresis.

Cysteinyl-leukotrienes (cys-LTs) are potent smooth muscle contracting agents, which play key roles in inflammatory and allergic diseases. The committed step in cys-LT biosynthesis is catalyzed by leukotriene C(4) synthase (LTC4S) as well as microsomal glutathione S-transferase type 2 (MGST2) and type 3 (MGST3). Here we report that intraperitoneal injections of lipopolysaccharide in rats lead to a strong increase of LTC4S messenger RNA (mRNA) levels after approximately 1 h, particularly in the heart, brain, adrenal glands and liver, without any significant effect on MGST2 and MGST3 mRNA levels. After 6 h, LTC4S mRNA returns to basal levels, concomitant with a 4.9-, 4.0-, 2.9- and 2.3-fold induction of LTC4S protein in brain, heart, liver and adrenal gland, respectively. Hence, challenge with lipopolysaccharide in vivo causes an organ-selective, local priming for leukotriene C(4) synthesis. Moreover, these data suggest that LTC4S and cys-LTs may be involved in acute systemic inflammatory responses such as fever and tachycardia.

Animals↗
PubMed2005

Monitoring of implant stability in grafted bone using resonance frequency analysis. A clinical study from implant placement to 6 months of loading.

The aim of this prospective study was to compare implants placed in grafted and normal non-grafted maxilla by means of resonance frequency analysis (RFA), clinical stability and implant failure. Twenty-nine patients with severe atrophy of the edentulous maxilla were treated with autogenous bone grafts as onlay (24 patients) or as interpositional grafts in conjunction with a Le Fort I osteotomy (five patients) 6 months prior to placement of 222 implants. Ten non-grafted patients treated with 75 Brånemark implants in the edentulous maxillae served as a control group. RFA was performed at implant placement, abutment connection and after 6 months of bridge loading. Seventeen (8%) implants were lost in the grafted bone and one (1%) in normal bone. RFA revealed a similar pattern in both grafted and normal maxillae, i.e. increasing resonance frequency (RF) with time (Wilcoxon Signed Rank test for paired data). Twenty implants that were rotation mobile (low primary stability) at the time of insertion showed a significantly lower value at implant placement according to RFA (Mann-Whitney U-test, P = 0.020). The RF for the failed implants revealed a tendency towards lower values (Mann-Whitney U-test, P = 0.072), compared to the successful implants. It is concluded that implants placed in grafted bone when using a two-stage technique achieve a stability similar to that of implants placed in normal non-grafted bone.

Aged↗
PubMed2005

Large social disparities in spontaneous preterm birth rates in transitional Russia.

OBJECTIVE: This study estimated the effect of maternal sociodemographic, obstetric and lifestyle factors on the risk of spontaneous preterm birth in a Russian town. METHODS: All women with singleton pregnancies registered at prenatal care centres in Severodvinsk in 1999 comprised the cohort for this study (n=1559). Analysis was based on spontaneous live singleton births at the maternity home (n=1103). Multivariable logistic regression was applied to quantify the effect of the studied factors on the risk of preterm birth. Differences in gestation duration were studied using multiple linear regression. RESULTS: In total, 5.6% of all spontaneous births were preterm. Increased risks of preterm delivery were found in women with lower levels of education and in students. Placental complications, stress and a history of fetal death in previous pregnancies were also associated with elevated risks for preterm delivery. Smoking, hypertension and multigravidity were associated with reduced length of pregnancy in metric form. CONCLUSION: In addition to medical risk factors, social factors are important determinants of preterm birth in transitional Russia. Large disparities in preterm birth rates may reflect the level of inequalities in transitional Russia. Social variations in pregnancy outcomes should be monitored.

Adolescent↗
PubMed2005

Serum lipids, glucose and insulin levels in healthy schoolchildren aged 9 and 15 years from Central Sweden: reference values in relation to biological, social and lifestyle factors.

BACKGROUND: There is a shortage of reference values for cardiovascular risk factors such as serum lipids, glucose and insulin related to biological, social and lifestyle factors for Swedish children and adolescents. Such values are needed for planning and evaluation of public health activities, and for clinical use. DESIGN AND METHODS: Data for this cross-sectional, school-based study were collected during a school year (September to May). A random sample of 1137 girls and boys aged 9 and 15 years from two locations in central Sweden participated in the study, and blood samples were taken from 969 of them. METHODS: Fasting serum blood samples were analysed for triglycerides, total cholesterol, high-density lipoprotein cholesterol, glucose and insulin. Physical examination included measurement of height, weight and pubertal status. Questionnaires provided family background data. Total physical activity was measured by accelerometer registration. RESULTS: Serum levels differed significantly between age and gender groups and were correlated to pubertal status. Neither genetic nor socio-economic background nor smoking status influenced the serum levels. Insulin levels were elevated in subjects with a body mass index in the highest decentile, compared with the levels in the rest of the subjects. The insulin levels were inversely associated with total physical activity, and physical activity varied with season. CONCLUSIONS: Pubertal status (biological age) should to be considered in the interpretation of serum values in schoolchildren rather than chronological age. The interpretation of insulin values should include both body mass index and physical activity level, and perhaps also season. Previously described regional differences in serum lipid levels in Swedish adults seem to be present also in children.

Adolescent↗
PubMed2004

Class separation of buildings with high and low prevalence of SBS by principal component analysis.

In this study, we were able to separate buildings with high and low prevalence of sick building syndrome (SBS) using principal component analysis. The prevalence of SBS was defined by the presence of at least one typical skin, mucosal and general (headache and fatigue) symptom. Data from the Swedish Office Illness Study describing the presence and level of chemical compounds in outdoor, supply, and room air, respectively, were evaluated together with information about the buildings in six models. When all data were included the most complex model was able to separate 71% of the high prevalence buildings from the low prevalence buildings. The most important variable that separates the high prevalence buildings from the low prevalence buildings was a more frequent occurrence or a higher concentration of compounds with shorter retention time in the high prevalence buildings. Elevated relative humidity in supply and room air and higher levels of total volatile organic compounds in outdoor and supply air were more common in high prevalence buildings. Ten building variables also contributed to the separation of the two classes of low and high prevalence buildings.

Air Pollutants↗
PubMed2003

Physical activity monitoring in Europe. The European Physical Activity Surveillance System (EUPASS) approach and indicator testing.

OBJECTIVES: The main objective of this paper is to describe the approach and specific findings of the European Physical Activity Surveillance System (EUPASS) research project. In particular, the analysis presented aims at testing the reliability, comparability and predictive power of different sets of physical activity (PA) indicators. DESIGN: First, a panel study based on computer-aided telephone interview (CATI) was designed to report PA data of a representative, selected group of about 100 persons per country at three points in time. Second, a CATI time series survey was carried out with the goal of realising about 100 interviews per month over six consecutive months. SETTING: The project was carried out in eight European countries to support the development of the European Union's (EU) Health Monitoring Programme. SUBJECTS: Random population samples (subjects aged 18 years and older) were drawn from each participating country. RESULTS: While many PA indicators used in EU countries to date as well as the psychosocial and environmental measures tested in the present study had acceptable to good reliability coefficients, the test-retest reliability scores of the International Physical Activity Questionnaire (IPAQ) version tested (the short (last 7 days) telephone interview IPAQ; IPAQ-S7T) were rather low. The comparability between extant national PA items and the IPAQ-S7T was low for all countries. The strongest predictors of perceived health were the psychosocial and environmental PA indicators. CONCLUSIONS: According to the results of the present study, more research is needed to further investigate and improve the quality of the IPAQ. In addition, the specific predictive power of the tested psychosocial and environmental PA indicators on perceived health should be of particular interest for designing health surveillance activities in the future.

Adolescent↗
PubMed2001

Heart rate as an indicator of the intensity of physical activity in human adolescents.

The aims of this study were, in a group of adolescents, firstly to identify the absolute heart rates (HR) and the percentages of maximal heart rates (HRmax) corresponding to 40%, 60% and 80% of peak oxygen uptake (PVO2), secondly to identify absolute and relative (%PVO2) oxygen uptakes (VO2) corresponding to HR of 120, 140 and 160 beats.min-1, and thirdly to examine a possible effect of fatness and fitness on the relationship between HR and VO2. The subjects were 127 (60 boys, 67 girls) adolescents with a mean age of 14.8 (SD 0.3) years. The HR and VO2 were measured by means of an incremental exercise test to exhaustion. Linear regressions were performed for the HR-VO2 and VO2-HR relationships using absolute and relative (%HRmax, %PVO2) data for each individual. From these regressions, target HR and VO2 were computed. Average target HR corresponding to 40%, 60% and 80% of PVO2 were: 119 (SD 9), 145 (SD 9), 171 (SD 8), and 120 (SD 10), 146 (SD 8), 172 (SD 8) beats.min-1 for boys and girls, respectively. Average VO2 corresponding to HR of 120, 140 and 160 beats.min-1 were: 22 (SD 5), 30 (SD 5), 38 (SD 6) and 18 (SD 4), 24 (SD 4), 31 (SD 4) mlO2.kg-1.min-1 for boys and girls, respectively. An analysis of covariance showed a significant fitness effect (P < 0.001) for predicted VO2 at all HR studied. The results suggest that the use of absolute HR to define exercise intensity levels when assessing young people's physical activity using HR monitoring detracts from the validity of the interpretation of the data.

Adolescent↗
PubMed2001

Physical activity in relation to aerobic fitness and body fat in 14- to 15-year-old boys and girls.

The purpose of this study was to examine the strength of the relationship between different variables of physical activity and aerobic fitness and body fat in adolescent boys and girls. Activity energy expenditure (AEE), time spent in a sedentary state, and time spent engaged in moderate and vigorous physical activity (MVPA, > or = 50% peak oxygen uptake, VO2peak) were assessed by the minute-by-minute heart rate monitoring method in 82 randomly selected 14- to 15-year olds (42 boys, 40 girls). Body fat was determined by measuring skinfold thicknesses. VO2peak was measured by indirect calorimetry. Somatic maturity level was determined by percentages of adult (i.e. 18 years) height attained at examination. AEE was related to aerobic fitness for both genders (boys, r = 0.30, P = 0.056; girls, r = 0.45, P = 0.003). For boys, there was a significant relationship between maturity level and VO2peak (r = 0.48, P < 0.001). For both genders, body fat was significantly and negatively related to VO2peak (r = -0.48 and r = -0.43, P < 0.01). Body fat and maturity explained 47% of the variation in VO2peak in boys, whereas AEE and body fat explained 22% of the variation in VO2peak in girls. No significant associations between physical activity variables and the data on body fat were observed. The total amount of physical activity (AEE) was related to VO2peak, at least in adolescent girls. Although VO2peak seems to be influenced by the maturity level in adolescent boys, the data support the promotion of a daily active lifestyle among young people.

Adipose Tissue↗
PubMed2001

Patients attachment patterns and response to a program for alleviating cardiovascular risk factors: a 1-year follow-up of patients in a patient education program.

This study was a 1-year follow-up of 295 consecutive patients at a patient education centre and assessed how attachment style influenced the outcome of the patient education program devised for individuals with multiple risk factors for cardiovascular disease. The program consisted of a 4-week residential program course, followed by a 4-day follow-up course a year later. In our cohort study, the 295 consecutive patients (mean age = 52years, S.D.=9.2) with multiple risk factors for cardiovascular disease, showed an initial overall reduction of 4.4 kg in weight (P=0.0001) and a reduction of 17/11 mm in systolic and diastolic blood pressure (P=0.0001 and 0.0001). The weight remained essentially the same at the follow-up 1 year later, whereas blood pressure tended to return to previous level. The attachment style was determined by means of a questionnaire: 87% were classified as 'secure', 9% 'avoidant' and 5% as 'ambivalent'. After 4 weeks, the ambivalent category had reduced weight (body mass index (BMI)) more than the secure group (P=0.04). At the 1-year follow-up, the avoidant category showed a more pronounced reduction in diastolic blood pressure than the other groups (P=0.001). Thus, it seems as if attachment style does have some influence on outcome. Patient education should take advantage of knowing patients' attachment style.

Cardiovascular Diseases↗
PubMed2001

Human umbilical vein endothelial cells generate leukotriene C4 via microsomal glutathione S-transferase type 2 and express the CysLT(1) receptor.

Certain immunocompetent myeloid cells, such as eosinophils, basophils and mast cells, have a large capacity to synthesize the potent proinflammatory and spasmogenic mediator leukotriene (LT) C4 via a specific microsomal glutathione S-transferase (MGST) termed LTC4 synthase (LTC4S). Here, we report that MGST2, a distant homologue of LTC4S, is abundantly expressed in Human umbilical vein endothelial cells (HUVEC) and converts LTA4 into a single product, LTC4. Thus, using Northern blot, RT-PCR, Western blot, and enzyme activity assays, we show that MGST2 is the main, if not the only, enzyme that converts LTA4 into LTC4 in membrane preparations of HUVEC. In fact, we failed to detect any expression of LTC4S, MGST1 or MGST3 in these cells, indicating that MGST2 is a critical enzyme for transcellular LTC4 biosynthesis in the vascular wall. Unlike LTC4S, MGST2 prefers the naturally occurring free acid of LTA4 over the methyl ester as substrate and is also susceptible to product inhibition with an IC50 of about 1 microM for LTC4. Moreover, HUVEC were found to express the CysLT1 receptor in line with a paracrine and autocrine role for cysteinyl-leukotrienes in endothelial cell function.

Blotting, Northern↗
PubMed2001

Breastfeeding in countries of the European Union and EFTA: current and proposed recommendations, rationale, prevalence, duration and trends.

UNLABELLED: Recommendations suggest exclusive breast feeding for at least the first 4 to 6 months after birth. Paradoxically, an overwhelming proportion of breast feeding (BF) data in Europe refers to all BF, i.e. not only exclusive but also partial BF (including formula, juices, water, sweetened water etc). This makes it difficult to estimate to what extent the recommendations are met. There is currently strong evidence for recommending exclusive breast feeding for at least 6 months. Exclusive BF has progressively gained scientific support. Prevention of infections, allergies and chronic diseases and a favourable cognitive development are highlighted in the recent scientific literature. Further long-term studies on the effects of BF on prevention of chronic disease in the adult are needed. Great differences exist in BF prevalence and duration both within and between European countries. Trends point towards higher prevalence and duration, with some exceptions. Young mothers breast feed less than older mothers; single and/or less educated mothers breast feed less than married mothers with more education. However, inefficient and unreliable monitoring systems prevail, and the data are scarce, not only on exclusive BF but also on demographic, socio-economic, psychosocial and medical determinants of BF patterns. National BF coordinators have not been appointed in many countries, and only every second country has promotion of BF incorporated into their national plan of action for nutrition. CONCLUSIONS: Efficient surveillance systems, comparable across Europe and using common definitions and methodology, need to be developed. These should include determinants of breast feeding. A European consensus conference should urgently be organised, in which strategies for successful promotion of exclusive BF should be particularly considered. There is now strong evidence for a recommendation to breast feed exclusively for about 6 months, which is more than the duration recommended previously.

Breast Feeding↗
PubMed2001

The school setting: an opportunity for the implementation of dietary guidelines.

Nutrition, physical activity and health related promotion programmes in schools have developed into a mature field of research over the past decades. A number of success factors have been identified and evidence-based interventions have been performed. However, the school setting as an arena for evidence-based health promotion programmes, is still not used to its full potential. Schools provide an excellent arena for reaching large segments of the population, such as young people, school staff, families and the surrounding community. There is a need for an overview regarding the current status of nutrition, physical activity, related health as well as support structures in the EU member states. Based upon such an analysis, a consensus report should be written, pointing out the major problems at hand. Self-assessment tools for national as well as for school level should be produced, in order to guide changes, but also to include an element of continuous assessment of change, for evaluation purposes.

Child↗
PubMed2001

Breastfeeding determinants and a suggested framework for action in Europe.

This is a background paper for the EURODIET initiative. A number of international initiatives and documents were identified, such as the Baby-Friendly Hospital Initiative, the International Code of Marketing of Breast Milk Substitutes and a number of consensus reports from professional groups, that propose ways forward for breastfeeding promotion. These point at a range of initiatives on different levels. The determinants for successful breastfeeding have to be identified. They can be categorised into five groups; socio-demographic, psycho-social, health care related, community- and policy attributes. A framework for future breastfeeding promoting efforts on European level is suggested, within which these determinants are considered. A common surveillance system needs to be built in Europe, where determinants of breastfeeding are included. There is also a need for a surveillance system which makes it possible to use the collected data on local level, not only on national and supranational level. Combined with a thorough review of the effectiveness of already existing breastfeeding promotion programmes, a co-ordinated EU-EFTA action plan on breastfeeding should be formulated and implemented within a few years. Urgent action could take place in parallel, especially targeting young, low-income, less educated mothers.

Breast Feeding↗
PubMed2001

Breast-feeding in Europe--rationale and prevalence, challenges and possibilities for promotion.

The status reports and other information collected showed that interpretation of the data on breast-feeding prevalence and duration collected at national or regional level within European countries is difficult, since this information is not collected in every country or it is gathered under different criteria. However, there seem to be vast differences in prevalence of breast-fed children and breast-feeding duration between European countries and possibly within countries. There is a need to establish monitoring systems enabling comparability of data between countries. Assessing determinants for breast-feeding is required as well. There are a number of important consensus documents supporting breast-feeding action. These documents are related to either one or more of the following categories: health benefits of breast-feeding; recommendations regarding breast-feeding duration and exclusiveness; providing guidance on breast-feeding promotion. Current recommendation is exclusive breast-feeding for 6 months.

Adult↗