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Biomedical subjects

R Andersson

Publications and source records attributed to R Andersson.

At least 37 records · Page 2Linked to original sources
PubMed2002

Force to restore the shape of an asymmetric extracorporeal tube as the basis for non-invasive pressure measurements.

A zero-balance principle is described where intraluminal pressure is estimated from the counter force needed to restore the tube shape of an elastic extra corporeal tube. The aim was to optimise cross-sectional tube geometry for tube expansion due to pressure and to reduce the sensitivity to variation in mechanical tube characteristics using an experimental statistical and factorial design. The main application is pressure monitoring in blood and dialysate tubes during hemodialysis. Improving the monitoring of the dialysis process will reduce complications, such as sudden decreases in systemic blood pressure or occlusion at the artero-venous fistula. The factorial design indicated strong influence from the geometrical characteristics of the tube as well from the geometrical design parameters of the pressure transducer. We found a consistent relationship between the intraluminal pressure and the applied force needed to restore the tube shape. The modified cross-sectional tube geometry enhances measurement sensitivity and facilitates the desired behavior of tubes during pressure applications.

Biophysical Phenomena↗
PubMed2001

Elective splenectomy in the elderly--perioperative and long-term course.

BACKGROUND: The hazards of elective splenectomy in the elderly have not been thoroughly investigated. The aim was to assess such a well-defined cohort with respect to perioperative and long-term outcome. METHODS: Fifty-two consecutively splenectomised patients during the period 1971-1995, aged 65 years or older, were followed until death (44 cases) or the end of 1999 (8 cases). RESULTS: No intraoperative deaths occurred, while three patients (5.8%) died postoperatively in the 1970s. Twenty-four patients suffered from thirty-four postoperative complications, dominated by infections and haematomas. No differences were seen comparing patients with and without complications related to the American Society of Anesthesiologists' classes, total transfusion rate, steroid medication, preoperative risk diseases, "giant spleens" or the time period during which the operations were performed. In 69% of the patients, the splenectomy was beneficial. During the long-term follow-up, 25 patients suffered from 59 infectious and thromboembolic episodes and 1 surgical complication. The dominating causes of death were the primary disease (29%), myocardial infarction (20%), sepsis (12%) and cerebrovascular lesions (12%), i.e. not directly related to late effects of the operation. CONCLUSION: High-risk patients older than 65 years with haematological disorders can safely undergo splenectomy with a low mortality rate and a reasonable rate of morbidity. The long-term course demonstrates a fair response rate, minimal surgically related complications, but thromboembolic and infectious events, and the majority of deaths unrelated to late effects of the splenectomy.

Aged↗
PubMed2001

The Swedish system for quality assessment of agricultural soils.

Soil quality assessment is based on the concept of soil functions. The performances of three soil functions, crop production, biological decomposition and matter exchange with the atmosphere and groundwater, are used as quality criteria. Soil properties that can be used as indicators for the degree of functional performance were identified. Each soil property selected was graded into five classes--from best (class 1) to worst (class 5). Grading was based biological on boundary conditions as well as on statistical distribution. The system outlined can be used to interpret the quality state of agricultural soils, provides for a relative comparison between soils, and may be helpful in an environmental monitoring program to assess trends in data.

Crops, Agricultural↗
PubMed2001

Canadian Aboriginal communities and medical service patterns for the management of injured patients: a basis for surveillance.

Growing attention has been placed on injury as a major public health problem which has served to highlight the need for relevant injury data for preventive purposes at the community level. In the case of reserve-based Aboriginal communities in Canada, available injury data, from large datasets, often has little or no relevance at the community level. In addition, the availability of local data is complicated by unique health service and community infrastructures. As such, a prerequisite to establishing injury surveillance requires an understanding of Medical Service Patterns (MSPs) for injured patients intrinsic to a community's health service infrastructure. In determining patterns, cultural and environmental contexts are integral to methodological considerations as historically, Canada's Aboriginal population has been 'controlled' by others in the areas of health, education and social services. The objective of the study was to investigate MSPs in a Canadian Aboriginal community, specific to the management of injured patients, for the purpose of identifying data sites, sources, and collectors. The method relied on a four-step qualitative process designed explicitly for the study community, comprising: (1) semi-structured interviews with key informants; (2) a flow diagram process; (3) focus group discussions; and (4) a summary matrix diagram. This methodology was later replicated with three additional pilot communities. Three major MSPs were identified from nine original patterns generated through the initial data collection process. MSPs were found to be most directly impacted by severity of injury and the proximity of health service providers. Data collection practices were inconsistent, sporadic and poorly coordinated. Data was exclusive to respective data sources and off-reserve documentation was not reported back to the community. MSPs identified key data sites, sources, and collectors relevant to the study population. In conclusion, the four-step qualitative methodology employed in the study was found to be reliable and feasible in identifying community MSPs. Empirical findings confirm the need to investigate MSPs in communities considering surveillance activities, as intra-national differences may be considerable given social inequalities, geographic uniqueness and cultural factors. The use of sophisticated methodologies may detract rather than promote collaborative efforts.

Alberta↗
PubMed2001

Comparison of starch branching enzyme I and II from potato.

The in vitro activities of purified potato starch branching enzyme (SBE) I and II expressed in Escherichia coli were compared using several assay methods. With the starch-iodine method, it was found that SBE I was more active than SBE II on an amylose substrate, whereas SBE II was more active than SBE I on an amylopectin substrate. Both enzymes were stimulated by the presence of phosphate. On a substrate consisting of linear dextrins (chain length 8-200 glucose residues), no significant net increase in molecular mass was seen on gel-permeation chromatography after incubation with the enzymes. This indicates intrachain branching of the substrate. After debranching of the products, the majority of dextrins with a degree of polymerization (dp) greater than 60 were absent for SBE I and those with a dp greater than 70 for SBE II. To study the shorter chains, the debranched samples were also analysed by high-performance anion-exchange chromatography. The products of SBE I showed distinct populations at dp 11-12 and dp 29-30, whereas SBE II products had one, broader, population with a peak at dp 13-14. An accumulation of dp 6-7 chains was seen with both isoforms.

1,4-alpha-Glucan Branching Enzyme↗
PubMed2001

Effects of inhibition of PAF, ICAM-1 and PECAM-1 on gut barrier failure caused by intestinal ischemia and reperfusion.

BACKGROUND: The role of cell adhesion molecules and transmigration of PMNs through the endothelial barrier is probably essential in intestinal ischemia and reperfusion (I/R)-induced gut barrier dysfunction. Although cytokines are released in I/R, it is unclear whether cytokines directly increase permeability or if this phenomenon requires both expression of cell adhesion molecules and PMN adhesion-activation. Endothelial barrier dysfunction plays an important role in the pathogenesis of multiple organ dysfunction syndrome, inducing gut barrier failure, but the mechanisms are not fully understood. The purpose of this study was to evaluate the potential therapeutic value of inhibition of platelet activating factor (PAF), intercellular adhesion molecule-1 (ICAM-1), and platelet endothelial cell adhesion molecule-1 (PECAM-1) in gut barrier dysfunction induced by intestinal I/R. METHODS: A PAF antagonist (lexipafant, BB-882) and monoclonal antibodies against rat ICAM-1 (anti-ICAM-1-MAb) and PECAM-1 (anti-PECAM-1-MAb) were used in a model of gut barrier dysfunction caused by intestinal ischemia for 40 min and concomitant reperfusion for 12 h in the rat, and endothelial permeability, myeloperoxidase activity, interleukin-1beta and protease inhibitor levels were evaluated. RESULTS: The endothelial permeability and tissue leukocyte recruitment in the distal small intestine significantly increased in rats with I/R treated with saline. Proteolytic activity in plasma was evident by low levels of the three measured plasma protease inhibitors. These changes were, to different degrees, reduced by treatment with lexipafant, anti-ICAM-1-MAb, or anti-PECAM-1-MAb. Alterations in systemic levels of interleukin-1beta paralleled the changes found in gut barrier permeability and leukocyte trapping. CONCLUSIONS: Our results suggest that treatment with the PAF inhibitor lexipafant and monoclonal antibodies against ICAM-1 or, seemingly most efficient, PECAM-1 reduces the severity of I/R-associated intestinal dysfunction, associated with a decrease in systemic concentrations of IL-1beta local leukocyte recruitment, and partly restoring plasma protease inhibitor levels.

Animals↗
PubMed2001

Vertebral osteomyelitis in Göteborg, Sweden: a retrospective study of patients during 1990-95.

Vertebral osteomyelitis (VO) is a rare condition and the diagnosis is often overlooked initially. Delay in diagnosis may result in vertebral destruction or perforation of the spinal canal. We suggest diagnostic criteria in order to simplify the diagnosis and classification of VO. Medical records of 58 patients with VO from Göteborg during the years 1990-95 were studied retrospectively. The incidence, clinical presentation, microbiology and treatment of VO were evaluated. The median age at the time of admission was 59 y (range 13-83 y) and the male:female ratio was 1.6:1. The incidence was 2.2/100,000 inhabitants/y. Sixty-four percent of the patients were natives of Sweden. The patients were classified as definite (67%), probable (26%) and possible (7%) VO. Staphylococcus aureus was the most common infective agent (34%), followed by Mycobacterium tuberculosis (27%). The most common risk factors included recent or current infections, immunosuppressive diseases and previous surgery. CRP and ESR were elevated in 82% and 88% respectively and plain X-ray changes indicating VO were found in 56% of the patients. Radiological changes were found in 34/44 (77%) computerized tomography scans and 10/13 (77%) magnetic resonance imaging examinations. The median duration of intravenous and oral antibiotic treatment were 10 and 179 d respectively. A delay of > I month from the onset of symptoms until diagnosis was found in 38% of the patients. This indicates the need for a standardized protocol for diagnosing VO. In this paper we suggest diagnostic criteria, which have not previously been available.

Adolescent↗
PubMed2001

Socio-demographic risk factors for home-type injuries in Swedish infants and toddlers.

UNLABELLED: In this paper we use data from Swedish national registers to study socio-demographic patterns of hospital admissions as a result of injuries sustained at home (poisoning, falls, scalding and ingestion/intrusion of foreign objects) in children 0-3 y. The study population comprised 546 336 children born in Sweden during the period 1987-91. The different injury mechanisms peaked at different ages: ingestion of foreign objects at 10-12 mo, scald injuries at 13-15 mo, non-drug poisoning at 16-18 mo and drug poisoning at 24-30 mo. In a multivariate analysis it was demonstrated that children of young mothers (<24 y) were more likely to have been admitted to hospital because of fall injuries and poisonings, while children with more than two siblings had a slightly increased risk for all injuries. Children of mothers born in a non-western country were more likely to have been admitted to hospital because of scald injuries; odds ratio (OR) 1.7 (95% CI: 1.4-2.1), while they were less likely to have been admitted because of fall injuries; OR 0.8 (0.7-0.8) and non-drug poisoning; OR 0.5 (0.4-0.6). Children in families who received social welfare benefits were more likely to have been admitted to hospital because of fall injuries; OR 1.3 (1.2-1.4), drug poisoning; OR 1.8 (1.7-2.0), non-drug poisoning; OR 1.4 (1.3-15) and scald injuries; OR 1.1 (1.1-1.5), while injuries with ingestion/intrusion of foreign objects tended to vary little with socio-economic indicators. CONCLUSION: Infants and toddlers in families with young mothers and in families on social welfare are at particular risk for home injuries in Sweden. The knowledge that the risk of poisoning, scalding and ingestion of foreign objects is related to specific ages can be used in timing of parent counselling.

Accidental Falls↗
PubMed2001

The impact of structural factors on the injury rate in different European countries.

BACKGROUND: A previous study pointed to there being two kinds of injuries--those with a mainly social genesis and those with a mainly environmental genesis. The aim of this study was to analyse how socioeconomic factors--such as level of economic development, alcohol consumption and unemployment and more cultural factors--such as education and religion--relate to kinds of injury. METHODS: Motor vehicle traffic accidents were chosen to represent injuries with a predominantly environmental genesis and suicides those with a mainly social genesis. Qualitative comparative analysis (QCA) complemented by Pearson correlation was employed. The data come from 12 European countries. RESULTS: Four groups of countries emerged from the analysis. Group 1 was high on both kinds of injuries and was also high on all the independent variables considered. Group 2 was low on social injuries and high on environmental injuries; it had a low level of economic development, high alcohol consumption and a high proportion of Roman Catholics. Group 3 was high on social injuries and low on environmental injuries; it had a high level of economic development, low alcohol consumption and few Roman Catholics. Group 4 was low on both kinds of injuries; the independent variables formed a similar pattern to those of group 3. CONCLUSION: The pattern for traffic fatalities differs from that of suicides. There is also patterning with regard to structural factors; economic level, education and religion seem to be more important with regard to injury rate differentials than alcohol consumption or unemployment.

Accidents, Traffic↗
PubMed2001

Canadian Aboriginal communities: a framework for injury surveillance.

At the international level, evidence supports the position that regardless of whether a country is industrialized or less developed, vulnerable populations living in poor social conditions are at disproportionate risk of injury. The Aboriginal population of Canada is one such vulnerable population. In addition to poor social conditions and marginalization related to historical injustices, this population is faced with the challenge of working with little or no descriptive injury data relevant to the community level. It has been and continues to be a significant barrier to the adoption and implementation of injury prevention strategies and programs. Recognizing that surveillance is an intrinsic component of public health practice, this study was undertaken to address a critical data gap facing Aboriginal communities. The objective of the study was to develop the conceptual design of an injury surveillance framework that would be culturally relevant, that is 'acceptable and owned by the target population', and would meet the specific requirements for injury data and data collection methods for the study population. The methodology was undertaken with focus groups at national and community levels, and relied on the use of strategic activities such as benchmarking, guided discussions, nominal group technique exercises and critical document reviews. The process of benchmarking served to identify that injury surveillance systems described in the literature, linking data to action, are not a predominant reality. The locus of control is often removed from the population of interest and resides primarily with experts under the jurisdiction and control of designated authorities. In order for the surveillance system to have cultural relevance, the focus group identified that the locus of control must be defined by the population of interest at the community level, and that the system must be germane and flexible to consider the local environment. The Aboriginal framework proposed places the locus of control with the community, in partnership with its data sources. Surveillance activities remain largely distinct from communities of interest, leading us to consider whether structural changes can serve to promote a link between data and action. Traditional or standard surveillance systems, by virtue of their structure, promote a disassociation between information and community action. Data management under the complete jurisdiction of sources external to a community appears to obstruct potential linkages between information and action.

Benchmarking↗
PubMed2001

The involvement of multiple protease-antiprotease systems and gut origin sepsis in zymosan-associated endothelial barrier injury and multiple organ dysfunction in rats.

Multiple organ dysfunction syndrome is a dominant cause of mortality in the intensive care unit. Experimentally, a condition similar to the multiple organ dysfunction syndrome can be induced by the intraperitoneal injection of sterile zymosan. In the present study we investigate potential alterations in multiple organ functions, endothelial permeability, and antiproteinases after intraperitoneal injection of zymosan at various doses. Zymosan-induced generalized inflammation lead to endothelial barrier injury in multiple organs/tissues, a decrease in systemic arterial pressure, impaired organ function and gut defence function, and consumption of protease inhibitors, particularly the consumption of alpha2 antiplasmin. Endothelial barrier injury appears to present a dose- and organ-dependent pattern in multiple organs/tissues, and the increase in endothelial barrier permeability occurred prior to organ dysfunction. Zymosan induced the development of multiple organ dysfunction syndrome, probably initiating multiple protease-antiprotease systems, particularly the fibrinolytic system, leading to endothelial barrier injury, tissue edema, parenchymal cell damage, and eventual organ dysfunction, potentially augmented by a secondary bacterial infection.

Animals↗
PubMed2001

Infection with cagA- and vacA-positive and -negative strains of Helicobacter pylori in a mouse model.

To study the role of cytotoxin-associated protein (cagA) and vacuolating cytotoxin (vacA) in Helicobacter pylori infection in an experimental murine model, mice were infected with seven strains with different cagA and vacA status. Groups of 10 NMRI mice were challenged and were killed 5 weeks later. In a second study, 20 mice were challenged with a mixture of the same seven strains and killed 1, 3, 15 and 17 weeks post-inoculation. All seven strains were found to colonize the mice for the 5-week experimental period. Animals infected with vacA-positive strains, regardless of cagA status, showed an elevation of antibody titers. Two cagA-negative and vacA-positive strains and one cagA- and vacA-positive strain were found to 'take over' in the mixed infection as analyzed by the randomly amplified polymorphic DNA-polymerase chain reaction technique and in one mouse stomach we found coexistence of two of the strains. We found no evidence of the different strains colonizing different parts of the stomach.

Animals↗
PubMed2001

An asymmetric dialysis tube as an integrated part of a pressure-monitoring sensor.

A sensor has been designed consisting of a tube holder with a force transducer and a tube with a modified cross-section. The holder has a lid that encloses the tube. By having a stiff holder and a compliant tube, the idea is that the intraluminal pressure in the tube can be obtained from the measured force. The method is intended for non-invasive pressure measurements in blood or dialysate tubes. We have used a tube cross-sectional geometry where the outer surface is elliptic and the inner surface is circular with a relation of 2:1 between the thinnest and thickest tube sides. The pressure transducer system shows a linear relationship between the applied pressure and the sensor output (r=0.999). Within the temperature range, 32 degrees --36 degrees C, which corresponds to the blood and dialysate temperatures, the sensor accuracy is within +/- 0.8 kPa (+/- 6 mm Hg). This indicates that the sensor should be clinically useful during dialysis and similar applications.

Blood Pressure Monitors↗