Showing papers by "Linköping University published in 1999"

Worldwide variations in the prevalence of symptoms of atopic eczema in the International Study of Asthma and Allergies in Childhood.

Abstract: BACKGROUND: Little is known about the prevalence of atopic eczema outside Northern Europe. OBJECTIVES: We sought to describe the magnitude and variation in the prevalence of atopic eczema symptoms throughout the world. METHODS: A cross-sectional questionnaire survey was conducted on random samples of schoolchildren aged 6 to 7 years and 13 to 14 years from centers in 56 countries throughout the world. Those children with a positive response to being questioned about the presence of an itchy relapsing skin rash in the last 12 months that had affected their skin creases were considered to have atopic eczema. Children whose atopic eczema symptoms resulted in sleep disturbance for 1 or more nights per week were considered to have severe atopic eczema. RESULTS: Complete data was available for 256,410 children aged 6 to 7 years in 90 centers and 458,623 children aged 13 to 14 years in 153 centers. The prevalence range for symptoms of atopic eczema was from less than 2% in Iran to over 16% in Japan and Sweden in the 6 to 7 year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range. Higher prevalences of atopic eczema symptoms were reported in Australasia and Northern Europe, and lower prevalences were reported in Eastern and Central Europe and Asia. Similar patterns were seen for symptoms of severe atopic eczema. CONCLUSIONS: Atopic eczema is a common health problem for children and adolescents throughout the world. Symptoms of atopic eczema exhibit wide variations in prevalence both within and between countries inhabited by similar ethnic groups, suggesting that environmental factors may be critical in determining disease expression. Studies that include objective skin examinations are required to confirm these findings.

A novel pulsed magnetron sputter technique utilizing very high target power densities

Abstract: Using a novel pulsed power supply in combination with a standard circular flat magnetron source, operated with a Cu target, a peak power density of 2800 W cm -2 was achieved. This results in a very intense plasma with peak ion current densities of up to 3.4 A cm −2 at the substrate situated 10 cm from the target. The ionized fraction of the deposited Cu flux was estimated to be approximately 70% from deposition rate measurements. The potential for high-aspect-ratio trench filling applications by high power pulsed magnetron sputtering is demonstrated by deposition in via-structures. The high power pulsed technique also results in a higher degree of target utilization and an improved thickness uniformity of the deposited films compared with conventional d.c. magnetron sputtering.

The intestinal microflora in allergic Estonian and Swedish 2-year-old children.

Abstract: Background The prevalence of allergic diseases seems to have increased particularly over the past 35–40 years. Furthermore, allergic disease is less common among children in the formerly socialist countries of central and Eastern Europe as compared with Western Europe. It has been suggested that a reduced microbial stimulation during infancy and early childhood would result in a slower postnatal maturation of the immune system and development of an optimal balance between TH1- and TH2-like immunity. Aims To test the hypothesis that allergic disease among children may be associated with differences in their intestinal microflora in two countries with a low (Estonia) and a high (Sweden) prevalence of allergy. Methods From a prospective study of the development of allergy in relation to environmental factors, 29 Estonian and 33 Swedish 2-year-old children were selected. They were either nonallergic (n = 36) or had a confirmed diagnosis of allergy (n = 27) as verified by typical history and at least one positive skin prick test to egg or cow's milk. Weighed samples of faeces were serially diluted (10−2–10−9) and grown under anaerobic conditions. The counts of the various genera and species were calculated for each child. In addition, the relative amounts of the particular microbes were expressed as a proportion of the total count. Results The allergic children in Estonia and Sweden were less often colonized with lactobacilli (P < 0.01), as compared with the nonallergic children in the two countries. In contrast, the allergic children harboured higher counts of aerobic micro-organisms (P < 0.05), particularly coliforms (P < 0.01) and Staphylococcus aureus (P < 0.05). The proportions of aerobic bacteria of the intestinal flora were also higher in the allergic children (P < 0.05), while the opposite was true for anaerobes (P < 0.05). Similarly, in the allergic children the proportions of coliforms were higher (P < 0.05) and bacteroides lower (P < 0.05) than in the nonallergic children. Conclusions Differences in the indigenous intestinal flora might affect the development and priming of the immune system in early childhood, similar to what has been shown in rodents. The role of intestinal microflora in relation to the development of infant immunity and the possible consequences for allergic diseases later in life requires further study, particularly as it would be readily available for intervention as a means for primary prevention of allergy by the administration of probiotic bacteria.

Role of nitrogen in the formation of hard and elastic CN x thin films by reactive magnetron sputtering

Abstract: Carbon nitride films, deposited by reactive dc magnetron sputtering in Ar/N2 discharges, were studied with respect to composition, structure, and mechanical properties. CNx films, with 0

PCR detection of genes encoding nitrite reductase in denitrifying bacteria

Abstract: Using consensus regions in gene sequences encoding the two forms of nitrite reductase (Nir), a key enzyme in the denitrification pathway, we designed two sets of PCR primers to amplify cd1- and Cu-nir. The primers were evaluated by screening defined denitrifying strains, denitrifying isolates from wastewater treatment plants, and extracts from activated sludge. Sequence relationships of nir genes were also established. The cd1 primers were designed to amplify a 778 to 799-bp region of cd1-nir in the six published sequences. Likewise, the Cu primers amplified a 473-bp region in seven of the eight published Cu-nir sequences. Together, the two sets of PCR primers amplified nir genes in nine species within four genera, as well as in four of the seven sludge isolates. The primers did not amplify genes of nondenitrifying strains. The Cu primers amplified the expected fragment in all 13 sludge samples, but cd1-nir fragments were only obtained in five samples. PCR products of the expected sizes were verified as nir genes after hybridization to DNA probes, except in one case. The sequenced nir fragments were related to other nir sequences, demonstrating that the primers amplified the correct gene. The selected primer sites for Cu-nir were conserved, while broad-range primers targeting conserved regions of cd1-nir seem to be difficult to find. We also report on the existence of Cu-nir in Paracoccus denitrificans Pd1222.

Anterior cruciate ligament reconstruction and the long-term incidence of gonarthrosis.

Abstract: Knee ligament injuries are common in sport. A rupture of the anterior cruciate ligament (ACL) is the most serious of these injuries because it may cause long term disability. In this literature review, the frequency of post-traumatic gonarthrosis is examined. There are few long term prospective studies but a number of retrospective studies with follow-up times between 5 and 20 years have been published. These studies show that radiographic gonarthrosis is significantly increased after all knee injuries compared with the uninjured joint of the same patient. Isolated meniscus rupture and subsequent repair, or partial or total ruptures of the ACL without major concomitant injuries, seem to increase the risk 10-fold (15 to 20% incidence of gonarthrosis) compared with an age-matched, uninjured population (1 to 2%). Meniscectomy in a joint with intact ligaments further doubles the risk of gonarthrosis (30 to 40%), and 50 to 70% of patients with complete ACL rupture and associated injuries have radiographic changes after 15 to 20 years. Thus, an ACL rupture combined with meniscus rupture or other knee ligament injuries results in gonarthrosis in most patients. Ten to 20 years after ACL injury, gonarthrosis often presents as a slight joint space reduction or, occasionally, joint space obliteration (Ahlback grades I to II), but is usually not associated with major clinical symptoms. According to the few longitudinal studies, the progress of gonarthrosis is slow, and in some cases the condition seems to remain stable. Time is an important determinant for the degree of gonarthrosis and problems demanding treatment may be encountered only at > 30 years after the initial accident.

Localization of the insulin receptor in caveolae of adipocyte plasma membrane

Abstract: The insulin receptor is a transmembrane protein of the plasma membrane, where it recognizes extracellular insulin and transmits signals into the cellular signaling network. We report that insulin r ...

Third‐Party Logistics: Is There a Future?

Abstract: In this article, the authors describe the results of a study on strategies of third‐party logistics (TPL) providers. The size of the TPL industry and the different requirements placed on logistics as opposed to basic services, such as transportation or public warehousing, justify the need to treat TPL as a separate industry. The authors describe three waves of entrants into the TPL industry and a taxonomy for value creation by logistics providers. Empirical findings for a strategic segmentation of the industry are presented. The strategic segmentation is connected to the waves of entrants and the taxonomy by an evaluation of required skills of TPL players. The TPL industry will soon reach an initial stage of maturity, but further changes are to be expected.

The relationship of arsenic levels in drinking water and the prevalence rate of skin lesions in Bangladesh.

Abstract: To determine the relationship of arsenic-associated skin lesions and degree of arsenic exposure, a cross-sectional study was conducted in Bangladesh, where a large part of the population is exposed through drinking water. Four villages in Bangladesh were identified as mainly dependent on wells contaminated with arsenic. We interviewed and examined 1,481 subjects [Greater/equal to] 30 years of age in these villages. A total of 430 subjects had skin lesions (keratosis, hyperpigmentation, or hypopigmentation). Individual exposure assessment could only be estimated by present levels and in terms of a dose index, i.e., arsenic levels divided by individual body weight. Arsenic water concentrations ranged from 10 to 2,040 microg/L, and the crude overall prevalence rate for skin lesions was 29/100. After age adjustment to the world population the prevalence rate was 30. 1/100 and 26.5/100 for males and females, respectively. There was a significant trend for the prevalence rate both in relation to exposure levels and to dose index (p < 0.05), regardless of sex. This study shows a higher prevalence rate of arsenic skin lesions in males than females, with clear dose-response relationship. The overall high prevalence rate in the studied villages is an alarming sign of arsenic exposure and requires an urgent remedy.

Antibiotic Susceptibility Among Aerobic Gram-negative Bacilli in Intensive Care Units in 5 European Countries

Abstract: Antibiotic suseptibility among aerobic gram-negative bacilli in intensive care units in 5 European countries.

DSP integrated circuits

Abstract: DSP Integrated Circuits. VLSI Circuit Technologies. Digital Signal Processing. Digital Filters. Finite Word Length Effects. DSP Algorithms. DSP System Design. Architectures for DSP. Synthesis of DSP Architectures. Digital Systems. Processing Elements. Integrated Circuit Design. Subject Index.

Hypertension and Arsenic Exposure in Bangladesh

Abstract: —A prevalence comparison of hypertension among subjects with and those without arsenic exposure through drinking water was conducted in Bangladesh to confirm or refute an earlier observatio...

Substituted polythiophenes designed for optoelectronic devices and conductors

Abstract: Polythiophenes are a very versatile class of conjugated polymers. Substituted polythiophenes can be tailored for various applications by designing the side groups to give the polymer different desired properties. Our work on preparing polythiophenes designed to have high stability in the doped state is described. We also discuss our efforts on tuning the colour of the emission from polythiophenes for use in polymer light-emitting diodes. Design criteria for the synthesis of polythiophenes with high luminescence efficiency for use in light-emitting diodes and lasers are also described. Finally, the design of polythiophenes for use in photodiodes is discussed.

Nutritional and occupational factors influencing the risk of Parkinson's disease: a case-control study in southeastern Sweden

Abstract: PURPOSE AND METHODS: To investigate the possible impact of nutritional and environmental risk factors for idiopathic Parkinson's disease (IP), a case-control study was performed in the county of Os ...

Principles and practice of the laser-Doppler perfusion technique

Abstract: This paper reviews the development and use of laser-Doppler perfusion monitors and imagers over the past two decades. The enormous interest in microvascular blood perfusion coupled with the ease of use of the technique has led to 1500+ publications citing its use. However, useful results can only be achieved with an understanding of the basic principles of the instrumentation and its application in the various clinical disciplines. The basic theoretical background is explored and definitions of blood perfusion and laser-Doppler perfusion are established. The calibration method is then described together with potential routes to standardisation. A guide to the limitations in application of the technique gives the user a clear indication of what can be achieved in new studies as well as possible inadequacy in some published investigations.

Particle trace visualization of intracardiac flow using time‐resolved 3D phase contrast MRI

Abstract: The flow patterns in the human heart are complex and difficult to visualize using conventional two-dimensional (2D) modalities, whether they depict a single velocity component (Doppler echocardiography) or all three components in a few slices (2D phase contrast MRI). To avoid these shortcomings, a temporally resolved 3D phase contrast technique was used to derive data describing the intracardiac velocity fields in normal volunteers. The MRI data were corrected for phase shifts caused by eddy currents and concomitant gradient fields, with improvement in the accuracy of subsequent flow visualizations. Pathlines describing the blood pathways through the heart were generated from the temporally resolved velocity data, starting from user-specified locations and time frames. Flow trajectories were displayed as 3D particle traces, with simultaneous demonstration of morphologic 2D slices. This type of visualization is intuitive and interactive and may extend our understanding of dynamic and previously unrecognized patterns of intracardiac flow.

Medin: an integral fragment of aortic smooth muscle cell-produced lactadherin forms the most common human amyloid.

Abstract: Aortic medial amyloid is a form of localized amyloid that occurs in virtually all individuals older than 60 years. The importance and impact of the amyloid deposits are unknown. In this study we have purified a 5.5-kDa aortic medial amyloid component, by size-exclusion chromatography and RP-HPLC, from three individuals, and we have shown by amino acid sequence analysis that the amyloid is derived from an integral proteolytic fragment of lactadherin. Lactadherin is a 364-aa glycoprotein, previously known to be expressed by mammary epithelial cells as a cell surface protein and secreted as part of the milk fat globule membrane. The multidomain protein has a C-terminal domain showing homology to blood coagulation factors V and VIII. We found that the main constituent of aortic medial amyloid is a 50-aa-long peptide, here called medin, that is positioned within the coagulation factor-like domain of lactadherin. Our result is supported by the specific labeling of aortic medial amyloid in light and electron microscopy with two rabbit antisera raised against two synthetic peptides corresponding to different parts of medin. By using in situ hybridization we have shown that lactadherin is expressed by aortic medial smooth muscle cells. Furthermore, one of the synthetic peptides forms amyloid-like fibrils in vitro. Lactadherin was not previously known to be an amyloid precursor protein or to be expressed in aortic tissue. The structure of lactadherin may implicate an important regulatory function in the aorta.

Different intestinal permeability patterns in relatives and spouses of patients with Crohn’s disease: an inherited defect in mucosal defence?

Abstract: Background—A familial defect in intestinal barrier function has been found in Crohn's disease. Aim—To investigate possible genetic and environmental influences on this barrier defect by studying intestinal permeability in both relatives and spouses of patients with Crohn's disease. Subjects—The study included 39 patients with Crohn's disease, 34 healthy first degree relatives, and 22 spouses. Twenty nine healthy volunteers served as controls. Methods—Intestinal permeability was assessed as the lactulose:mannitol ratio in five hour urinary excretion after oral load, both before (baseline) and after ingestion of acetylsalicylic acid. The permeability response represents the difference between the two tests. A ratio above the 95th percentile for controls was classified as abnormal. Results—Baseline permeability was higher in patients and spouses than in controls. An abnormal baseline permeability was seen in 36% of the patients, 23% of the spouses, 18% of the relatives, and 3% of the controls. After ingestion of acetylsalicylic acid, permeability increased significantly in all groups. Relatives were similar to patients with regard to permeability after exposure to acetylsalicylic acid, whereas spouses were similar to controls. The proportions with an abnormal permeability response to acetylsalicylic acid were 32% in patients, 14% in spouses, 41% in relatives, and 3% in controls. Conclusion—The findings suggest that baseline permeability is determined by environmental factors, whereas permeability provoked by acetylsalicylic acid is a function of the genetically determined state of the mucosal barrier, and support the notion that environmental and hereditary factors interact in the pathogenesis of Crohn's disease. Keywords: acetylsalicylic acid; environment; genetics; inflammatory bowel disease; lactulose; mannitol

Changes of trapezius muscle blood flow and electromyography in chronic neck pain due to trapezius myalgia

Abstract: Chronic neck pain may increase the transmitter activity of neuropeptides in the upper cervical medulla causing impairment of the blood flow in the local muscle because of a lack of vasodilatatory substances excreted axonally. We have been using a new single-fibre technique for clinical determination of the microcirculation (LDF) in the trapezius muscles in relation to electromyography (EMG). This study pertains to the 76 patients (46 women and 30 men) who received a final diagnosis of chronic trapezius myalgia out of a total series of 300 cases with chronic neck pain which had been remitted to the National Insurance Administration Hospital in Tranas, Sweden, because their complaints interfered with their working ability. The purpose was to derive more objective medical information upon which to base rehabilitation. Sixty percent had continuous pain and 40% had pain after physical effort, or at work. Twenty healthy women volunteered to participate as a normal control group. The right and left trapezius muscles of all individuals were examined simultaneously with laser-Doppler flowmetry (LDF) and surface EMG during a fatiguing series of stepwise-increased contractions, each of 1 min duration with 1 min rest in between. The most painful side was compared with the opposite side in all patients and, in the female patients, also with the right shoulder of the healthy control women. The patients showed consistently low local blood flow in the painful side. The difference was statistically significant at low contraction intensities. Muscle tension was somewhat elevated, as evidenced by a slight increase of the rms-EMG that was statistically significant at high contraction intensities. The mean power frequency (MPF) of the EMG showed no change. The lowered local blood flow was not explained by a changed intramuscular pressure which is low in the trapezius during ordinary activities that do not normally impair the local blood flow (Larsson, S-E., Cai, H. and Oberg, P.A., Microcirculation in the upper trapezius muscle during varying levels of static contraction, fatigue and recovery in healthy women. A study using percutaneus laser-Doppler flowmetry and surface electromyograpy, Eur. J. Appl. Physiol., 66 (1993) 483–488). We conclude that an impaired regulation of the microcirculation in the local muscle is of central importance in chronic trapezius myalgia, causing nociceptive pain which can be differentiated objectively from neuralgic neck-shoulder pain by the atraumatic technique described.