Biomedical subjects

M Magnusson

Publications and source records attributed to M Magnusson.

At least 19 recordsLinked to original sources

PubMed2006

Bioaccumulation of 14C-PCB 101 and 14C-PBDE 99 in the marine planktonic copepod Calanus finmarchicus under different food regimes.

Bioaccumulation factors (BAFs) were determined for (14)C-PCB 101 and (14)C-PBDE 99 in the pelagic copepod Calanus finmarchicus after exposure to either contaminated water or after being fed contaminated phytoplankton (the dinoflagellate Prorocentrum minimum or the diatom Thalassiosira weissflogii). BAFs in algae range from 7.6 to 8.0 for PCB 101 and from 8.5 to 8.6 for PBDE 99. BAFs in copepods were significantly lower, 6.3-6.8 for PCB 101 and 7.6 for PBDE 99. For each compound, the BAFs in copepods were independent of what algal species they had consumed, even though the bioaccumulation of both compounds were higher in P. minimum than in T. weissflogii. The ratios between BAF and the K(ow) for PCB 101 and PBDE 99 were similar within each of the three species, but varied between species. For copepods the ratios were 2-4, for T. weissfloggii 15-22 and for P. minimum 32-40. The data strongly suggest that the two compounds bioaccumulate in a similar manner and that there is no biomagnification in the transfer between phytoplankton and herbivorous copepods.

Animals↗

PubMed2006

Mondini-like malformation mimicking otosclerosis and superior semicircular canal dehiscence.

In 2003, it was reported that superior semicircular canal dehiscence can mimic otosclerosis because of low-frequency bone conduction hearing gain and dissipation of air-conducted acoustic energy through the dehiscence. We report the case of a 17-year-old girl with left-sided combined hearing loss thought to be due to otosclerosis. Bone conduction thresholds were -10 dB at 250 and 500 Hz and she had a 40 dB air-bone gap at 250 Hz. When a tuning fork was placed at her ankle she heard it in her left ear. Acoustic reflexes and vestibular evoked myogenic potentials could be elicited bilaterally. Imaging of the temporal bones showed no otosclerosis, superior semicircular canal dehiscence or large vestibular aqueduct, but a left-sided, Mondini-like dysplasia of the cochlea with a modiolar deficiency could be seen. Mondini-like cochlear dysplasia should be added to the causes of inner-ear conductive hearing loss.

Adolescent↗

PubMed2006

Survival time and period of catheterization in patients treated with percutaneous nephrostomy for urinary obstruction due to malignancy.

PURPOSE: To assess patient mortality and survival time, period of catheterization, and indications for percutaneous nephrostomy (PCN) withdrawal in patients treated with PCN for urinary obstruction due to malignancy. MATERIAL AND METHODS: A retrospective analysis of 151 patients treated with 257 PCNs in a 5-year period was performed. Data on survival time, duration of catheterization, and clinical end-points for PCN treatment were collected. RESULTS: The median survival time of the patients was 255 days, while median catheterization time was 62 days. The majority of patients (84) died with the catheter. Indications for PCN withdrawal were surgery, stent treatment, catheter displacement, and response to medical treatment. CONCLUSION: The majority of patients with malignancy treated with PCN have advanced disease and short life expectancy. Factors such as diagnosis, prognosis, economy, and the patient's preference influence the choice of urinary diversion method. However, PCN should be considered in patients with malignancy on grounds of safety and low cost.

Aged↗

PubMed2006

Identification of health problems at 18 months of age--a task for physicians or child health nurses?

BACKGROUND: Several studies have questioned the rationality of repeated routine health examinations by physicians during the first years of life. The aim of the present study was to evaluate the population-based 18-month health examination and compare the yield of new health problems identified by physicians in 1994 with the yield identified by child health centre (CHC) nurses in 2000. METHODS: Two populations of children were invited to their 18-month health examination during one year, the first in 1994 and the second in 2000. In 1994 the population consisted of 4075 and in 2000 of 2968 children who were registered in Uppsala county, Sweden, for census purposes in December 31 each year. Data from a county health register as well as child health records and information regarding referrals were analysed to categorize the health problems by type, severity and action taken. RESULTS: On the whole few new verified health problems were detected by the health examinations at the 18 month health examinations: 2.3% in 1994 and 1.7% in 2000. In 1994, when the physicians carried out the examinations, the most common health problems were somatic problems, particularly moderate transient infections. In 2000, when the nurses carried out the examinations, the dominant problems were speech problems. Peculiarly enough a couple of children with the same severe health problems, gluten allergy and problems in the autistic spectrum, were identified both in 1994 and in 2000. In addition the nurses in 2000 identified seven children with severe speech problems. No additional severe health problems were identified by the physicians in 1994. CONCLUSIONS: According to the present study, there is no evidence that health examinations carried out by nurses are of lower quality in detecting health problems than those carried out by physicians. The organization and content of the health surveillance programme ought to be reconsidered with respect to available resources and importance of the close relationship established between nurse and family already in the newborn period.

Clinical Competence↗

PubMed2006

Glycaemic and nonglycaemic effects of pioglitazone in triple oral therapy of patients with type 2 diabetes.

OBJECTIVES: To examine pioglitazone as add-on to metformin and insulin secretagogues in patients with type 2 diabetes and inadequate glycaemic control and its effect on glycaemic control, surrogate measures of insulin sensitivity (adiponectin) and beta-cell function (proinsulin/insulin) and fluid retention. DESIGN AND SETTING: Prospective open-label study of 54 patients with type 2 diabetes and HbA1c>or=6.5% admitted to outpatient unit at Malmö University Hospital. The patients received 30-45 mg pioglitazone daily during 26 weeks in addition to their existing antidiabetic medication. After 26 weeks, one-third of patients were followed for 3 months without pioglitazone. RESULTS: HbA1c decreased (7.8+/-0.9-6.3+/-0.9%, P<0.001) with 61% of patients achieving levels<6.5%. However, in the group followed for another 3 months HbA1c increased (6.1+/-0.73-7.1+/-0.9, n=18, P<0.001) after pioglitazone withdrawal. Adiponectin increased (6.1+/-2.8-13.2+/-5.8 microg mL-1, P<0.001) and the proinsulin to insulin ratio decreased (0.89+/-0.66-0.66+/-0.53, P<0.001). Nt-proBNP increased from 487.3+/-252.2 to 657.8+/-392.1 pmol L-1 (P<0.001). CONCLUSIONS: Pioglitazone is effective in achieving glycaemic targets and reducing risk factors involved in atherosclerosis and improving beta-cell function when used as part of triple oral therapy in patients with type 2 diabetes and secondary drug failure. Nt-proBNP increase with concomitant decrease in haemoglobin suggests a subclinical sign of fluid retention.

Adiponectin↗

PubMed2006

Effect of different premilking manual teat-cleaning methods on bacterial spores in milk.

Different teat-cleaning methods were evaluated to determine their effect on the presence of spores from anaerobic bacterial spore-formers in the milk. Artificial contamination was used to achieve uniform contamination of teats to reduce the number of cows and samples needed in the experiments and still obtain adequate power to detect differences among tested methods. Teats were contaminated experimentally with a large amount of Clostridium tyrobutyricum spores in a manure-water slurry. Various types of dry and moistened towels and different combinations of methods using soap or 2 types of towels, together with cleaning times of 10 or 20 s, were compared in 2 Latin square-designed experiments with 7 cows, 7 treatments, and 4 replications in each experiment. In comparison with control (no cleaning and no forestripping), cleaning teats with dry paper towels for 10 s reduced concentration of spores in milk by 45 to 50%. A 50 to 74% reduction was achieved using different types of moist towels for 10 s. Methods using 2 towels, soap, or a longer cleaning time reduced bacterial contamination by 85 to 91%. The most effective methods in reducing milk spore content (96% reduction) were use of a moist washable towel with or without soap followed by drying with a dry paper towel, for a total time of 20 s per cow. One of the best cleaning methods was studied in an additional experiment to determine the effect of different teat contamination mixtures. The Latin square-designed experiment with 8 cows, 8 treatments, and 2 replications showed that cleaning was independent of the tested contamination matrix (manure, soil, or sawdust), type of spores (Cl. tyrobutyricum and Bacillus cereus), or degree of contamination (manure or extra manure).

2-Propanol↗

PubMed2005

Treatment of phobic postural vertigo. A controlled study of cognitive-behavioral therapy and self-controlled desensitization.

In balance clinic practice, phobic postural vertigo is a term used to define a population with dizziness and avoidance behavior often as a consequence of a vestibular disorder. It has been described as the most common form of dizziness in middle aged patients in dizziness units. Anxiety disorders are common among patients with vestibular disorders. Cognitive-behavioral therapy is an effective treatment for anxiety disorders, and vestibular rehabilitation exercises are effective for vestibular disorders. This study compared the effect of additional cognitive-behavioral therapy for a population with phobic postural vertigo with the effect of self-administered vestibular rehabilitation exercises. 39 patients were recruited from a population referred for otoneurological investigation. Treatment effects were evaluated with the Dizziness Handicap Inventory, Vertigo Symptom Scale, Vertigo Handicap Questionnaire, and Hospital Anxiety and Depression Scale. All patients had a self treatment intervention based on education about the condition and recommendation of self exposure by vestibular rehabilitation exercises. Every second patient included was offered additional cognitive behavioral therapy. Fifteen patients with self treatment and 16 patients with cognitive- behavioral treatment completed the study. There was significantly larger effect in the group who received cognitive behavioral therapy than in the self treatment group in Vertigo Handicap Questionnaire and the Hospital Anxiety and Depression scale and its subscales. Cognitive-behavioral therapy has an additional effect as treatment for a population with phobic postural vertigo. A multidisciplinary approach including medical treatment, cognitive-behavioral therapy and physiotherapy is suggested.

Adult↗

PubMed2005

Three-dimensional rotational angiography of transplanted renal arteries: influence of an extended angle of rotation on beam-hardening artifacts.

PURPOSE: To investigate whether three-dimensional rotational angiography (3D-RA) of the transplant renal artery performed with an extended angle of rotation can reduce beam-hardening artifacts in 3D reconstructed images without image quality being lost or side effects to the transplanted kidney being increased. MATERIAL AND METHODS: 3D-RA with a C-arm rotation of 180 degrees was performed consecutively in 12 renal transplanted patients with suspicion of renal artery stenosis. A 1.7-mm balloon occlusion catheter was placed using the crossover technique and this was compared to a protocol with 160 degrees rotation and a traditional 1.4-mm catheter in 10 patients. The occurrence of beam-hardening artifacts was registered and the effects of the reduced contrast load on image quality and of arterial occlusion on renal function were assessed. RESULTS: The extended angle of rotation, from 160 degrees to 180 degrees, reduced the beam-hardening artifacts. Artifacts were observed in 4/11 patients (36%) in the study group and in all 10 (100%) of the controls. There was no statistical difference regarding image quality between the two protocols. Renal function was equally affected in both protocols. CONCLUSION: 3D-RA with an extended C-arm rotation reduced the beam-hardening artifacts. Image quality was not reduced despite the reduced contrast medium load. The different protocols had no effect on patient outcome.

Adult↗

PubMed2005

Nt-proANP in plasma, a marker of salt sensitivity, is reduced in type 2 diabetes patients.

OBJECTIVE: We recently showed that plasma concentration of N-terminal atrial natriuretic peptide (Nt-proANP) is strongly directly related to salt sensitivity. The aims of the present study were to test (i) whether plasma concentration of N-terminal brain natriuretic peptide (Nt-proBNP) is related to salt sensitivity and (ii) whether Nt-proANP, as a marker of salt sensitivity, differs between type 2 diabetes patients and nondiabetic subjects without a history of coronary heart disease. METHODS: Nt-proBNP was determined in 30 Swedish normal subjects with heredity for primary hypertension and salt sensitivity was defined as the difference between mean arterial blood pressure after 1 week on a high-salt diet (240 mmol day(-1)) and 1 week on a low-salt diet (10 mmol day(-1)). Nt-proANP was measured in 253 patients with type 2 diabetes and in 230 nondiabetic subjects aged 40-70 years, all without a history of coronary heart disease. RESULTS: Amongst the 30 subjects, in whom salt sensitivity was directly measured, Nt-proBNP was not correlated with salt sensitivity (R=-0.18, P=0.35). Nt-proANP (median, interquartile range) was lower in patients with type 2 diabetes (505, 387-661 pmol L(-1)) than in nondiabetic subjects (536, 421-696 pmol L(-1)) (P=0.02). In a multiple regression analysis heart rate (P <0.00001), diastolic blood pressure (P=0.02) and diabetes status (P=0.02) were inversely related whereas age (P <0.00001), cystatin C (P=0.0006), hypertension treatment (P=0.002) and female sex (P=0.006) were directly related to ln(Nt-proANP). CONCLUSION: In contrast to Nt-proANP, Nt-proBNP is not related to salt sensitivity. Salt sensitivity, as estimated by Nt-proANP, seems to be reduced in type 2 diabetes.

Atrial Natriuretic Factor↗

PubMed2005

Child health services in transition: I. Theories, methods and launching.

AIM: To describe an evidence-based model for preventive child health care and present some findings from baseline measurements. METHODS: The model includes: parent education; methods for interaction and language training; follow-up of low birthweight children; identification and treatment of postnatal depression, interaction difficulties, motor problems, parenthood stress, and psychosocial problems. After baseline measurements at 18 mo (cohort I), the intervention was tested on children from 0 to 18 mo at 18 child health centres in Uppsala County (cohort II). Eighteen centres in other counties served as controls. Two centres from a privileged area were included in the baseline measurements as a "contrasting" sample. Data are derived from health records and questionnaires to nurses and mothers. RESULTS: Baseline experiment (n = 457) and control mothers (n = 510) were largely comparable in a number of respects. Experiment parents were of higher educational and occupational status, and were more frequently of non-Nordic ethnicity. Mothers in the privileged area (n = 72) differed from other mothers in several respects. Experiment nurses devoted considerably fewer hours per week to child health services and to child patients than did control nurses. CONCLUSIONS: Despite certain differences, experiment and control samples appeared comparable enough to permit, in a second step, conclusions about the effectiveness of the intervention.

Child Health Services↗

PubMed2005

Child health services in transition: II. Mothers' perceptions of 18-month-old children in the light of socio-economic status and some subjective factors.

AIMS: To analyse mothers' self-assessed quality of interaction with their children and their opinions about child difficulty with respect to socio-economic status and subjective factors: postnatal depression, social isolation, sense of coherence and locus of control. METHODS AND MATERIAL: A comprehensive questionnaire was completed by 1039 mothers of 18-mo-old children participating in the baseline measurements of a Swedish multicentre study developing and testing a new psychosocial model for the child health services. RESULTS: All subjective factors, including the number of factors, showed significant associations with perceived interaction and difficultness. Effect sizes of subjective factors ranged from about 0.3 to 1 SD for interaction, and from about 0.2 to 0.8 SD for difficultness. As for difficultness, effect sizes were larger for boys. There were no associations between high socio-economic status and high-quality interaction or low child difficultness: the few significant differences in fact favoured low-status children. CONCLUSION: The results provided some contradictory findings to the well-known association between high socio-economic status and favourable outcome. This result is of practical relevance for interventions: supportive programmes cannot be limited to areas and families of low socio-economic status. Positive effects may ensue if subjective factors like those studied here can be promoted among parents and children through the child health services.

Child Health Services↗

PubMed2005

Improved postural control through repetition and consolidation.

Research regarding the optimal frequency of training in postural control rehabilitation has been sparse. Posturography with vibratory proprioceptive stimulation was performed with eyes open and closed on 36 healthy subjects divided into 3 groups. Each group was tested 5 times, though with different time-intervals; 20 minutes, 3 hours and 24 hours respectively. Two different adaptive processes seems to be involved in the formation of a new movement pattern when exposed to a postural disturbance, one fast adaptation active during each test occasion and a second adaptation active between the consecutive tests. As the same adaptation pattern was found regardless the repetition time interval, the results imply either that the consolidation process of the new motor memory is time-independent or that the stimulus was sufficiently strong to induce fast consolidation thus leaving the time-interval unimportant. The findings suggest that it is primarily the number of repetitions in the exercises that governs the outcome of training, whereas the time interval between the exercises is of less importance.

Adaptation, Psychological↗

PubMed2004

Balance control and adaptation during vibratory perturbations in middle-aged and elderly humans.

The objective was to investigate if healthy elderly people respond and adapt differently to postural disturbances compared to middle-aged people. Thirty middle-aged (mean age 37.8 years, range 24-56 years) and forty healthy elderly subjects (mean age 74.6 years, range 66-88 years) were tested with posturography. Body sway was evoked by applying pseudorandom vibratory stimulation to the belly of the gastrocnemius muscles of both legs simultaneously. The tests were performed both with eyes open and eyes closed. The anteroposterior body sway was measured with a force platform and analyzed with a method that considers the adaptive changes of posture and stimulation responses. The results showed that middle-aged people generally used a different postural control strategy as compared to the elderly. The elderly responded more rapidly to vibratory perturbation, used more high-frequency (>0.1 Hz) motions and the motion dynamics had a higher degree of complexity. Moreover, the elderly had diminished ability to use visual information to improve balance control. Altogether, despite having an effective postural control adaptation similar to that of middle-aged people, the elderly had more difficulty in withstanding balance perturbations. These findings suggest that the balance control deterioration associated with aging cannot be fully compensated for by postural control adaptation.

Adaptation, Physiological↗

PubMed2004

Effects of postural disturbances with fatigued triceps surae muscles or with 20% additional body weight.

One of the main issues for balance control is the ability to generate enough forces to execute motions and uphold stability. This study aimed to investigate whether induced fatigue of the triceps surae muscles and decreased muscle force due to temporary additional body weight affected the ability to withstand balance perturbations. Another aim was to examine whether postural control adaptation over time was able to compensate for the changes induced by fatigue and additional body weight. Eleven normal subjects were exposed to vibratory proprioceptive stimulation during three test conditions; a baseline test during normal condition; when the body weight was increased by 20%, by adding additional weight load; and when the triceps surae muscles were fatigued. The tests were performed both with eyes open and closed. The body movements were evaluated by analyzing the anteroposterior and lateral torques induced towards the supporting surface measured with a force platform. Postural control was substantially affected both by the additional body weight, and by muscle fatigue in the triceps surae muscles. The anteroposterior and lateral body sway were larger both with added weight and fatigued muscles compared with the baseline test during quiet stance. However, the body sway induced by the vibratory stimulation was significantly larger with additional body weight compared with when the triceps surae muscles were fatigued. The differences between the test conditions were mostly pronounced during tests with eyes closed and in the high frequency body sway (>0.1 Hz). Postural control adaptation was able to reduce but not fully compensate for the changes induced by fatigue and additional body weight. Several hypotheses could account for these observations. (1) Fatigued muscles are less sensitive to muscle vibration, (2) muscle fatigue alters the muscle contractile efficiency and thus alters the ability to produce high-frequency, short-latency responses to balance perturbations.

Adult↗

PubMed2003

Influence of neck proprioception on vibration-induced postural sway.

OBJECTIVE: Several reports have shown that the direction of the postural responses induced by vestibular stimulation is affected by the positions of the neck and torso. The aim of this study was to investigate whether the postural responses to vibratory proprioceptive stimulation of the calf muscles are affected by the position of the head and thus by proprioceptive and vestibular information from the neck and head. MATERIAL AND METHODS: Ten normal subjects were exposed to vibratory proprioceptive stimulation of the calf muscles when the head was maintained in five different positions: in a neutral position facing forwards, with the head turned to the right or left sides or with the head tilted backwards or forwards. Body movements were evaluated by analyzing the anteroposterior and lateral torques induced towards the supporting surface. RESULTS: The analysis showed that only the anteroposterior body sway was significantly affected by the position of the head. The anteroposterior postural responses were primarily increased during the tests with the head tilted backwards or forwards, whereas the postural responses were unaffected by head torsion towards the sides. The lateral responses were primarily affected by vision and not by the position of the head. CONCLUSIONS: The findings suggest that the responses evoked by vibratory proprioceptive stimulation of the calf muscles may be affected by different mechanisms, either by purely proprioceptive information or by an interaction between proprioceptive and vestibular information. Moreover, the increasing difference between the test conditions over time suggests that fatigue of the neck muscles may be one of the factors affecting the responses induced by the perturbations.

Adult↗

PubMed2003

Effects of hypothermic anesthesia of the feet on vibration-induced body sway and adaptation.

The aim of this study was to investigate the significance of information from the plantar cutaneous mechanoreceptors in postural control and whether postural control could compensate for reduced cutaneous information by adaptation. Sixteen healthy subjects were tested with eyes open or eyes closed with hypothermic and normal feet temperature during posturography where body sway was induced by vibratory proprioceptive stimulation towards both calf muscles. The hypothermic anesthesia was obtained by cooling the subject's feet in ice water for 20 minutes. Body movements were evaluated by analyzing the anteroposterior and lateral torques induced towards the supporting surface by a force platform during the posturography tests. The reduction of cutaneous sensor information from the mechanoreceptors of the feet significantly increased the vibration-induced torque variance mainly in the anteroposterior direction. However, the effects of disturbed mechanoreceptors information was rapidly compensated for through postural adaptation and torque variance was in level with that without anesthesia within 50 to 100 seconds of stimulation, both when standing with eyes open and eyes closed. Our findings suggest that somatosensory input from mechanoreceptors in the foot soles contribute significantly in maintaining postural control, but the sensory loss could be compensated for.

Adaptation, Physiological↗

PubMed2002

Analysis of short- and long-term effects of adaptation in human postural control.

The short-term (i.e., days) and long-term (i.e., months) effects of adaptation to posturography examinations were investigated in 12 normal subjects who were repeatedly examined for five consecutive days and again after 90 days. The examinations were conducted both with eyes open and closed, and the perturbations were evoked by a pseudorandomly applied vibration stimulation to the calf muscles. The evoked anteroposterior responses were analyzed with a method considering adaptation in the slow changes in posture and in the stimulus-response relationship. Repetition of examinations on a daily basis revealed a gradual improvement of postural-control performance. The body sway induced by the stimulation was significantly reduced and the dynamical properties changed. Most of the improvements remained after 90 days, but some parameters such as the complexity of the control system used were increased to the initial level. The results confirm previous observations that postural control contains several partially independent adaptive processes, observed in terms of alteration of posture and as a progressive reduction of body sway induced by stimulation. The method used for the adaptation analysis in this study could be applied to analyze biological systems with multiple individual adaptive processes with different time courses or characteristics, or where the adaptation processes are related to multiple internal or external factors.

Adaptation, Physiological↗

PubMed2002

Adaptation of postural control to perturbations--a process that initiates long-term motor memory.

The objective was to investigate postural control adaptation during daily repeated posturography with vibratory calf stimulation. The posturography was performed with eyes open and closed daily for 5 days and after 90 days on 12 healthy subjects. The postural control adaptation could be described as two separate processes, a rapid adaptation during the test progress and a long-term habituation between consecutive test days. The adaptive improvements gained during the 5 days consecutive testing, largely remained 90 days later but seemed restricted to the same test situation. The findings suggest that balance rehabilitation should include a variety of repeated exercises, which are sufficiently long to induce habituation.

Adaptation, Physiological↗