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Biomedical subjects

E Holmström

Publications and source records attributed to E Holmström.

16 recordsLinked to original sources
PubMed2006

Knee kinematics and kinetics during gait, step and hop in males with a 16 years old ACL injury compared with matched controls.

The objective of this study was to compare subjects who sustained an ACL injury during soccer 16 years ago with a control group with regard to knee kinematics and kinetics of gait, step activity and cross over hop. Secondly, in the injured subjects, the purpose was to study the impact on kinematics and kinetics of characteristics such as operative status, meniscal resection, being symptomatic, having knee extensor weakness and of having radiographic knee OA. Data from a 3-dimensional gait analysis system (VICON) were used to calculate kinetics and kinematics during gait, step activity and cross over hop of 12 male subjects who had an anterior cruciate ligament injury 16 years earlier. Twelve uninjured subjects matched for age, sex, BMI and activity level served as controls. No significant differences in knee kinematics and kinetics between the ACL group and the control group were found. The variability of some parameters of step and all parameters of hop activity was generally larger in the ACL injured subjects compared with the controls. The ACL injured subjects had a significantly worse clinical status compared with the controls. Reduced knee extension strength was associated with joint moment reductions especially during step activity and cross over hop. Despite a significantly worse clinical status, as determined by self-report and isokinetic strength testing, no significant differences were seen in knee joint kinetics and kinematics in an ACL injured group 16 years after injury compared with a matched control group. The variation was larger among the ACL injured subjects indicating the need for larger study groups in gait and movement analysis in long-term follow-up of ACL injury.

Adult↗
PubMed2006

Competing exchange interactions in magnetic multilayers.

We have studied alloying of the nonmagnetic spacer layer with a magnetic material as a method of tuning the interlayer coupling in magnetic multilayers. We have specifically studied the Fe/V(100) system by alloying the spacer V with various amounts of Fe. For some Fe concentrations in the spacer, it is possible to create a competition between antiferromagnetic Ruderman-Kittel-Kasuya-Yoshida exchange and direct ferromagnetic exchange coupling. The exchange coupling and transport properties for a large span of systems with different spacer concentrations and thicknesses were calculated and measured experimentally and good agreement between observations and theory was observed. A reduction in magnetoresistance of about 50% was observed close to the switchover from antiferromagnetic to ferromagnetic coupling.

Journal Article↗
PubMed2004

On the sharpness of the interfaces in metallic multilayers.

We show that the three most relevant magnetic properties (magnetic moment, critical temperature, and interlayer exchange coupling) of metallic multilayers can be reproduced with good accuracy by first principles theory, provided that the picture of atomically sharp interfaces is abandoned and one allows instead for both interface alloying and interface roughness. The interface of a metallic multilayer (exemplified by the Fe/V system) is demonstrated to, at best, have interdiffusion essentially over two to three atomic layers on each side of the interface. Our conclusions are the result of combining experimental work with theoretical modeling, and we argue that this approach is the best avenue to obtain accurate information about the interface quality of metallic multilayers.

Journal Article↗
PubMed2000

Vaccination responses to capsular polysaccharides of Neisseria meningitidis and Haemophilus influenzae type b in two C2-deficient sisters: alternative pathway-mediated bacterial killing and evidence for a novel type of blocking IgG.

Meningitis caused by Neisseria meningitidis serogroup W-135 was diagnosed in a 14-year-old girl with a history of neonatal septicemia and meningitis caused by group B streptococci type III. C2 deficiency type I was found in the patient and her healthy sister. Both sisters were vaccinated with tetravalent meningococcal vaccine and a conjugate Haemophilus influenzae type b vaccine. Three main points emerged from the analysis. First, vaccination resulted in serum bactericidal responses demonstrating anticapsular antibody-mediated recruitment of the alternative pathway. Second, addition of C2 to prevaccination sera produced bactericidal activity in the absence of anticapsular antibodies, which suggested that the bactericidal action of antibodies to subcapsular antigens detected in the sera might strictly depend on the classical pathway. A third point concerned a previously unrecognized type of blocking activity. Thus, postvaccination sera of the healthy sister contained IgG that inhibited killing of serogroup W-135 in C2-deficient serum, and the deposition of C3 on enzyme-linked immunosorbent assay plates coated with purified W-135 polysaccharide. Our findings suggested blocking to be serogroup-specific and dependent on early classical pathway components. Retained opsonic activity probably supported post-vaccination immunity despite blocking of the bactericidal activity. The demonstration of functional vaccination responses with recruitment of alternative pathway-mediated defense should encourage further trial of capsular vaccines in classical pathway deficiency states.

Adolescent↗
PubMed1999

Low concentrations of immunoglobulin G antibodies to Salmonella serogroup C in C2 deficiency: suggestion of a mannan-binding lectin pathway-dependent mechanism.

The influence of complement on immune responses to polysaccharides is debatable. We examined the serum concentrations of IgM and IgG antibody against Salmonella O-antigen specific oligosaccharides representing the serogroups B, C and D, and against capsular polysaccharides of Streptococcus pneumoniae serotypes 6 and 23 in C2-deficient adults and in healthy controls. A sharp contrast of findings was found for antibodies against the CO antigen, an activator of the mannan-binding lectin (MBL) pathway of complement activation. The C2-deficient group showed normal IgM and markedly low IgG antibody levels. Similar findings were made in adults with low concentrations of MBL. This suggests that the recruitment of classical pathway C3 convertase through the MBL pathway is critically involved in isotype switching of antibodies against MBL pathway activating antigens during immune system maturation. The findings imply a new role of the MBL pathway, and an additional link between innate and acquired immunity. Specific IgM against BO was moderately low in C2 deficiency. Other differences for the Salmonella antigens were not found. Markedly raised IgM antibody levels against pneumococcal polysaccharides in C2 deficiency probably Salmonella reflected past infections. The absence of a concomitant increase of specific IgG might possibly be explained by impaired IgM to IgG switching.

Adult↗
PubMed1998

Binding of properdin to solid-phase immune complexes: critical role of the classical activation pathway of complement.

The capacity of serum to support deposition of C3, properdin and factor B was studied by enzyme-linked immunosorbent assay using solid-phase immune complexes (IC) for activation of complement. Deposition of C3 and properdin occurred in fairly dilute normal human serum (NHS), but factor B uptake was hardly detectable. Alternative pathway-mediated deposition of C3 with slow kinetics was demonstrated in C2-deficient serum and in NHS depleted of C1q, factor D and properdin (C1qDP-depleted serum) after reconstitution with factor D and properdin. Efficient uptake of properdin required a functional classical pathway, in the presence of which C3 and properdin were rapidly deposited onto the IC. Judging from findings in C3-deficient serum, factor I-deficient serum, and C1qDPB-depleted serum, the uptake of properdin was strictly C3-dependent, and did not require the presence of factors B and D. Thus, C3b fixed to IC was the principal ligand for properdin in the assay. The findings could have biological implications relating to complement-mediated modification of immune complexes in disease.

Antigen-Antibody Complex↗
PubMed1996

Progression of atherosclerosis in middle-aged men: effects of multifactorial intervention.

OBJECTIVE: To determine the effect of multifactorial intervention against cardiovascular risk factors on ultrasound-determined progression of atherosclerosis in healthy middle-aged men. DESIGN: One hundred and forty-nine healthy middle-aged men were assigned to an intervention group (IG) or a control group (CG). SUBJECTS: The participants had moderately increased risk-factor scores for cardiovascular disease. They were recruited from a health screening programme at the Preventive Medicine Section, Department of Medicine, Lund University, University Hospital, Malmö. During the study period, 32 of the subjects were lost to follow-up, leaving 59 in the IG and 58 in the CG. INTERVENTION: The IG subjects underwent multifactorial intervention for 2 years, the goal being to help them stop smoking and to reduce their blood lipids and blood pressure. MAIN OUTCOME MEASURES: Intima-media thickness and plaque score in the right carotid artery were ultrasonographically determined initially and after 2 years. Blood lipids and blood pressure were measured at the same time, and in the IG also after 3, 6, 12 and 18 months after entry into the study. RESULTS: At the entry into the study, there were no significant differences in major risk factors or ultrasound variables between IG and CG. Blood lipids and smoking decreased significantly during the 2 years of intervention in the IG, whilst these factors remained unchanged in the CG. Intima-media thickness and plaque scores increased significantly in both groups. CONCLUSIONS: No effects on ultrasound variables could be detected after 2 years of multifactorial intervention. A more aggressive intervention programme, possibly more dependent on pharmacological treatment, may be required to obtain reduced progression or regression of atherosclerosis.

Adult↗
PubMed1993

Serum bactericidal activity and induction of chemiluminescence of polymorphonuclear leukocytes: complement activation pathway requirements in defense against Neisseria meningitidis.

Serum bactericidal activity and chemiluminescence (CL) responses of polymorphonuclear leukocytes (PMNL) to pathogenic Neisseria meningitidis serogroups B and W-135 and to nonpathogenic serogroup 29E were examined with pooled normal human serum depleted of the complement proteins C1q, factor D, properdin and C5. Purified C1q, factor D, properdin and C5 were added alone or in combination. For investigation of serogroup W-135 meningococci, a C1q, factor D and properdin-depleted postvaccination serum with high concentrations of anticapsular antibodies was also used. Serogroup B and W-135 cultured to log phase were resistant to the bactericidal activity of pooled normal human serum but were efficiently killed through the classical pathway alone when the bacteria were cultured to stationary phase. Nonpathogenic serogroup 29E meningococci in log or stationary growth phases were efficiently killed in serum, predominantly through the classical pathway. Serogroup W-135 meningococci grown to log phase were resistant to classical pathway-mediated bactericidal activity in postvaccination serum but were killed on addition of alternative pathway proteins. Stationary phase serogroup W-135 meningococci were killed through both pathways in the postvaccination serum. In the pooled normal human serum CL responses of PMNL were consistently more pronounced with fully reconstituted C1q, factor D, properdin, C5-depleted serum than with serum reconstituted with C1q, factor D and properdin suggesting contribution of actions related to terminal components. In the absence of C1q, serogroup W-135 meningococci in postvaccination serum induced a significant but delayed alternative pathway-mediated CL response. CL responses induced by serum-opsonized meningococci, in contrast to serum bactericidal activity, were not influenced by culture conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Bactericidal Activity↗
PubMed1992

Effects of lumbar belts on trunk muscle strength and endurance: a follow-up study of construction workers.

The effects on maximal isometric trunk muscle strength and endurance after wearing a soft heat-retaining lumbar belt or a weightlifter's belt were studied. The soft belt (SB) study group comprised 12 construction workers with healthy backs, and the weightlifter's belt (WB) group comprised 24 construction workers with current or previous low back pain. The strength and endurance measurements were performed before the start of belt use, and after 1 and 2 months. The SB group increased the trunk flexor strength by 13% (p less than or equal to 0.01) after 2 months. The WB group increased the trunk flexor strength and endurance by 12% and 29%, respectively (p less than or equal to 0.001). No significant decrease of trunk muscle strength and endurance was found at the end of the follow-up period.

Adult↗
PubMed1992

Trunk muscle strength and back muscle endurance in construction workers with and without low back disorders.

The aim of this study was to test the hypothesis that male workers exposed to heavy work and with no lifetime history of a low back disorder (group A) have better trunk muscle strength and back muscle endurance compared to male workers with the same work exposure but with a probable (group B) or definite low back disorder (group C). Group A (n = 42) was clinically negative on physical examination. Group B (n = 75) was clinically negative or uncertain and group C (n = 86) was clinically positive, with current or previous low back disorders occurring in both groups. Group A had a significantly higher mean intraindividual extension/flexion ratio, namely 1.29 versus 1.19, in group C. The mean values for maximum isometric trunk extension and flexion strength did not differ between the groups. The isometric trunk extensor endurance was significantly lower in group C than in both group A and group B.

Adult↗
PubMed1991

Cysteine residues are not essential for the catalytic activity of human class Mu glutathione transferase M1a-1a.

To investigate the possible involvement of a Cys thiol in the catalysis of the human glutathione transferase M1a-1a, we constructed mutants of this enzyme wherein the four Cys residues present in the native enzyme were replaced by Ala residues. Three mutants, one where all four Cys residues had been replaced and two mutants where three out of four Cys residues were changed into Ala, were characterized regarding their catalytic activities with three different substrates as well as by their binding of three different inhibitors. All three Cys-deficient mutant forms of glutathione transferase M1a-1a were catalytically active with the tested substrates and their binding of inhibitors, measured by I50, were not significantly different from the values previously obtained for the wild-type enzyme. We therefore conclude that none of the Cys residues in this class Mu glutathione transferase are directly involved in the catalysis performed by this enzyme.

Alkylating Agents↗
PubMed1991

Normal human serum depleted of C1q, factor D and properdin: its use in studies of complement activation.

Normal human sera were depleted of C1q, factor D (D) and properdin (P) by a simple and reproducible procedure providing reagents for analysis of complement-dependent functions. Classical pathway activity was restored with purified C1q, and alternative pathway activity with purified D and P. Since both activation pathways were abolished, antibodies and other components could be removed without loss of complement activity during immunoabsorption procedures. Synergism between the two pathways during haemolysis of rabbit erythrocytes was clearly demonstrated, and was also found on analysis of C3 cleavage in serum incubated with other alternative pathway activators such as zymosan and inulin. Experiments with a Neisseria meningitidis serogroup W-135 strain isolated from a patient with inherited P deficiency showed that both pathways were capable of supporting antibody-dependent killing of the bacteria in serum. The alternative pathway was possibly more efficient than the classical pathway in the assay system. In C1q,D,P-depleted serum with high concentrations of anticapsular IgG antibodies, the addition of D alone resulted in efficient alternative pathway-mediated killing. The alternative pathway was equally efficient in a C1q,D,P-depleted serum with low concentrations of anticapsular antibody, but in this case the reaction required both D and P.

Animals↗
PubMed1991

Low back pain--correspondence between questionnaire, interview and clinical examination.

The aim of this study was to analyse the correspondence between answers to a questionnaire about trouble from the musculoskeletal system, answers in a personal interview and clinical findings indicating low back disorder. The questionnaire was answered by 1,773 construction workers. Out of those, 206 workers underwent interview and clinical examination. Among those who reported no lifetime LBT in the questionnaire 63% gave the same report in the personal interview and those were all assessed negative at a blind clinical examination. Of those reporting current LBT in the interview 80% (47/59) were clinically positive. The clinical criteria used in the examination seemed to indicate lumbar painful structures. Answers to a question about functional impairment were in conformity with clinical findings. As regards answers to a question about frequency of pain and a question, in the specific Nordic questionnaire for the low back, concerning inability to do normal work the correlation to clinical findings was less apparent. Reported inability to do normal work in the questionnaire corresponded only to 43% with reported sick-leave in the interview.

Absenteeism↗
PubMed1985

Intra-abdominal pressure and trunk muscle activity during lifting. III. Effect of abdominal muscle training in chronic low-back patients.

Isometric training of the abdominal muscles is often recommended in programs of primary or secondary prevention for low-back pain. In this study 20 male workers with 2-18 years' history (average 5 1/2 years) of low-back pain without sciatica went through intense isometric abdominal muscle training for 5 weeks. Before and after training the subjects had trunk flexion and extension strength tests and a series of standardized lifts. The intraabdominal pressure (IAP) and the EMG activity of the oblique abdominal muscles, and of the erector spinae muscle were recorded. It was found that: the strength of the abdominal muscles increased; the increased strength was correlated to an improved recruitment of motor units in the oblique abdominal muscles; the EMG activity of the oblique abdominal muscles when lifting decreased after training, i.e. the acquired ability to recruit more motor units was not made use of; the IAP at lifting was generally not affected. A better knowledge of the mechanisms responsible for the IAP in different situations is needed to support advice on training or other prevention.

Abdomen↗
PubMedDate not supplied

Musculoskeletal disorders in construction workers.

Physical factors that contribute to musculoskeletal disorders in construction workers are described, and the clinical findings associated with muscular, tendon, articular, spinal, and peripheral nerve entrapment disorders are reviewed. Psychosocial factors and individual factors such as the worker's age, smoking habits, and endurance are considered.

Adult↗