| 1. |
- Harms-Ringdahl, K, et al.
(författare)
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Assessment of jet pilots' upper trapezius load calibrated to maximal voluntary contraction and a standardized load.
- 1996
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Ingår i: Journal of Electromyography & Kinesiology. - : Elsevier BV. - 1050-6411 .- 1873-5711. ; 6:1, s. 67-72
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Tidskriftsartikel (refereegranskat)abstract
- Electromyographic (EMG) recording of the myoelectrical activity level in the trapezius muscle is often used as one method of assessing neck and shoulder muscle workload. To analyse how the normalization value influences interpretation of upper trapezius load during a work task, two different reference values for normalization were applied - one obtained during a maximum voluntary contraction (MVE) and the other during a standardized muscular load (RVE). Nine jet pilots (ages 30-48 yr) flew two sorties in a 37 Viggen aircraft using either of two types of head garment while 3-D acceleration and muscular activity were recorded. In each sortie twice in the programme a steep left turn at 5-6 +G(Z) was performed. The highest activity level (MVE) obtained during shoulder elevation combined with an isometric heavy resistance (maximum) against arm flexion/abduction was used as one normalization value. Before, between, and after the two flights, 15 s EMG recordings (RVE) during a dumbbell test in the same arm position were also taken. The muscular activity in the upper trapezius during a given task varied a great deal between individuals, but the reliability of the amplitude levels on different occasions during a work day was good, given the same electrode location and application. If muscular activity during a standardized loading force (e.g. dumbbell test) is used to normalize the recordings for workload assessments related to utilized muscular capacity, a subject with high muscular strength and comparatively low workload might in some situations be assessed as having the same workload as, or a higher load than a subject with less strength and a comparatively high workload. While normalization using a standardized force can be used to assess changes in workload, for assessing workload related to the individual's capacity recording the myoelectrical activity during maximal contraction is preferable.
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| 2. |
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| 3. |
- Horsten, M, et al.
(författare)
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Psychosocial factors and heart rate variability in healthy women.
- 1999
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Ingår i: Psychosomatic Medicine. - : Ovid Technologies (Wolters Kluwer Health). - 0033-3174 .- 1534-7796. ; 61:1, s. 49-57
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: This study was conducted to investigate associations between psychosocial risk factors, including social isolation, anger and depressive symptoms, and heart rate variability in healthy women. METHODS: The study group consisted of 300 healthy women (median age 57.5 years) who were representative of women living in the greater Stockholm area. For the measurement of social isolation, a condensed version of the Interpersonal Support Evaluation List was used and household size assessed. Anger was measured by the anger scales previously used in the Framingham study and depressive symptoms by a questionnaire derived from Pearlin. Health behaviors were measured by means of standard questionnaires. From 24-hour ambulatory electrocardiographic monitoring, both time and frequency domain measures were obtained: SDNN index (mean of the SDs of all normal to normal intervals for all 5-minute segments of the entire recording), VLF power (very low frequency power), LF power (low frequency power), HF power (high frequency power), and the LF/HF ratio (low frequency by high frequency ratio) were computed. RESULTS: Social isolation and inability to relieve anger by talking to others were associated with decreased heart rate variability. Depressive symptoms were related only to the LF/HF ratio. Adjusting for age, menopausal status, exercise and smoking habits, history of hypertension, and BMI did not substantially change the results. CONCLUSIONS: These findings suggest heart rate variability to be a mediating mechanism that could explain at least part of the reported associations between social isolation, suppressed anger, and health outcomes.
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| 4. |
- Ingvarsson, P K, et al.
(författare)
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Extinction-recolonization dynamics in the mycophagous beetle Phalacrus substriatus
- 1997
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Ingår i: Evolution. - : Oxford University Press (OUP). - 0014-3820 .- 1558-5646. ; 51:1, s. 187-195
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Tidskriftsartikel (refereegranskat)abstract
- The population structure of the mycophagous beetle Phalacrus substriatus is characterized by many small, local populations interconnected by migration over a small spatial scale (10 X 75 m(2)). Each local P. substriatus population has a relatively short expected persistence time, but persistence of the species occurs due to a balance between frequent local extinctions and recolonizations. This nonequilibrium population structure can have profound effects on how the genetic variation is structured between and within populations. Theoretical models have stated that the genetic differentiation among local populations will be enhanced relative to an island model at equilibrium if the number of colonizers is less than approximately twice the number of migrants among local populations. To study these effects, a set of 50 local P. substriatus populations were surveyed over a four-year period to record any naturally occurring extinctions and recolonizations. The per population colonization and extinction rate were 0.237 and 0.275, respectively. Mark-recapture techniques were used to estimate a number of demographic parameters: local population size (N = 11.1), migration rate ((m) over cap = 0.366), number of colonizers (k = 4.0), and the probability of common origin of colonizers (phi = 0.5). The theoretically predicted level of differentiation among local populations (measured as Wright's F-ST) was 0.070. Genetic data obtained from an electrophoretic survey of seven polymorphic loci gave an estimated degree of differentiation of 0.077. There was thus a good agreement between the empirical results and the theoretical predictions. Young populations (<(theta)over cap>(young) = 0.090) had significantly higher levels of differentiation than old, more established populations (<(theta)over cap>(old) = 0.059). The extinction-recolonization dynamics resulted in an overall increase in the genetic differentiation among local populations by c. 40%. The global effective population size was also reduced by c. 55%. The results give clear evidence to how nonequilibrium processes shape the genetic structure of populations.
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| 5. |
- Jensen-Urstad, K, et al.
(författare)
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Heart rate variability in healthy subjects is related to age and gender.
- 1997
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772 .- 1365-201X. ; 160:3, s. 235-41
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Tidskriftsartikel (refereegranskat)abstract
- The effects of age and gender on heart rate variability as measured by spectral and time domain analysis of 24 h ECG recordings were evaluated in 101 healthy subjects, 49 men and 52 women (20-69 years of age). In the frequency domain, total power, very low-frequency power, low-frequency power and high-frequency power were negatively correlated to age (P < 0.001 for all variables). Total power decreased by 30% between 20-29 and 60-69 years of age. In the time domain, SDNN-index, the mean of the standard deviations of all normal R-R intervals for all 5 min segments of a 24 h ECG recording, was negatively correlated to age (P < 0.001). Total power, very low-frequency power, low-frequency power and the low-frequency/high-frequency ratio were lower in women (P < 0.05, P < 0.05, P < 0.01 and P < 0.01), although the absolute differences were much smaller than for age. There was a pronounced circadian variation; at night total power increased in all age groups (P < 0.01). The results show that age, and to a lesser degree gender, are important determinants of heart rate variability in healthy subjects. Heart rate variability is a valuable tool for risk stratification in cardiovascular disease, but the physiological effects of ageing, with diminishing heart rate variability in older age groups, must also be taken into account.
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| 6. |
- Jensen-Urstad, K, et al.
(författare)
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Pronounced resting bradycardia in male elite runners is associated with high heart rate variability.
- 1997
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 7:5, s. 274-8
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Tidskriftsartikel (refereegranskat)abstract
- Forty-eight hour Holter monitoring was undertaken of 16 male elite middle- and long-distance runners, age 25 +/- 3 years, with peak oxygen uptake 4.83 +/- 0.43 1 O2/min or 73.0 +/- 3.9 ml O2/kg/min. The athletes had pronounced bradycardia during the night-time, with heart rate calculated from four RR intervals < 30 beats/min in five runners. Twelve of 16 runners had RR intervals > 2 s. Of those, 10 runners had sinus pauses exceeding 2 s, the longest being 3.06 s. Three runners had AV block II, two with Mobitz type 1, and one with both Mobitz type 1 and 2. Autonomic function was estimated by time domain and power spectral analysis of heart rate variability. The runners were compared with a control group of 13 sedentary or moderately active subjects. The runners had a mean of 14 b.p.m. lower heart rate at night than the controls. The runners had higher heart rate variability in all spectral bands. In the time domain pNN50 and rMSSD, which are considered to reflect strongly vagal tone, were markedly higher in the runners than the controls. The findings suggest that an increased parasympathetic tone might at least partly explain the pronounced resting sinus bradycardias found in endurance-trained runners.
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| 7. |
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| 8. |
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| 9. |
- Ericson, Anna, et al.
(författare)
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Kinetics and Mechanism for Reduction of Gold(III) Complexes by Dimethylsulfide
- 1997
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Ingår i: Journal of the Chemical Society. Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1472-7773 .- 0300-9246 .- 1364-5447. ; 1997:7, s. 1159-1164
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Tidskriftsartikel (refereegranskat)abstract
- The reactions between trans-[Au(CN) 2 X 2 ] - (X = Cl or Br) and Me 2 S have been studied by conventional and high-pressure stopped-flow spectrophotometry in acidic aqueous solution containing 10% (w/w) methanol. The overall stoichiometry Au III ∶Me 2 S is 1∶(1.0 ± 0.1) in agreement with the reaction: trans-[Au(CN) 2 X 2 ] - + Me 2 S + H 2 O → [Au(CN) 2 ] - + Me 2 SO + 2H + + 2X - . Initial rapid substitution processes result in the formation of a pre-equilibrium between transient gold(III) complexes, which are reduced to [Au(CN) 2 ] - in a subsequent slower redox process. Complexes trans-[Au(CN) 2 X(Me 2 S)] with an asymmetric electron distribution along the X–Au–S axis are reduced rapidly via an intermolecular process, in which Me 2 S attacks a co-ordinated halide. The complex trans-[Au(CN) 2 (Me 2 S) 2 ] , on the other hand, undergoes slow reduction to gold(I) involving a water molecule. The rapid halide-mediated oxidation of thioethers implies that reduction of metal ions in biological systems by such moieties should be favoured in extracellular environments, where the chloride concentrations are high.
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| 10. |
- Ericson, Gunilla, 1955-
(författare)
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³²P-postlabelling analysis of DNA adducts in fish as a biomarker of genotoxic exposure
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The 32P-postlabelling assay was used for analysis of hydrophobic DNA adducts in fish as a biomarker of genotoxic exposure. DNA adducts were analysed in perch (Perca fluviatilis) and northern pike (Esox lucius), two relatively stationary fish species which are common in Swedish freshwater systems and along the Baltic coast. Experimental studies on time-course, dose-response and persistence of DNA adducts in liver and extrahepatic tissues of pike were performed in the laboratory. DNA adducts were readily formed in pike exposed to carcinogenic model substances. Oral exposure gave rise to higher adduct levels in both liver and intestine compared to intraperitoneal exposure. Following repeated oral exposure, adduct levels increased in a dose-related manner in liver, gills, brain and intestine, with highest levels in the intestine. No significant decrease in total adduct levels was observed in liver, gills and brain during a 78-day period after the last exposure, while adduct levels in intestine decreased to one third of the maximum value. DNA adducts in the intestine are probably removed due to a high cell turnover rate in this tissue, and may thus represent ongoing or relatively recent exposure.Perch and pike from minimally polluted sites were analysed at several occasions, including during the reproductive season for perch, with the results showing no detectable adducts, or very low levels. No adducts related to spawning season were detected in unexposed female or male perch.In a field investigation carried out in a pollution gradient of polycyclic aromatic hydrocarbons leading away from an aluminium smelter, adduct levels in liver and kidney were correlated to distance from the suspected point source and to contaminant levels in the sediment. Adduct levels in gills, spleen, blood and brain were also elevated in perch from the site closest to the smelter compared to the outermost site. Increased adduct levels in these tissues were correlated to effects on higher biological organisation levels, i.e. hepatocellular degeneration and decreased growth rate at the two innermost sites, and decreased spleen somatic index at the innermost site. Adduct levels were also increased in perch from a river with creosote-contaminated bottom sediments, indicating that potentially genotoxic compounds in the sediment were bioavailable to the fish. Exposure of perch in the laboratory to a solvent extract prepared from the contaminated sediment resulted in adduct patterns which closely resembled those obtained from field captured perch, thus verifying the origin of the genotoxic substances. Furthermore, increased DNA adduct levels in liver and intestine of feral fish from coastal waters receiving bleached kraft pulp mill effluents were detected.The results show that 32P-postlabelling analysis of hydrophobic DNA adducts in feral perch and pike can be used as a sensitive biomarker of exposure to potentially genotoxic compounds in the aquatic environment. Adduct levels in liver and several extrahepatic tissues were positively correlated to exposure concentrations. Levels of aromatic/hydrophobic DNA adducts in unexposed perch and pike can be considered as practically zero. DNA adducts thus exhibit a wide range in response, from almost zero in unexposed fish to high levels in exposed fish, which is desirable for a good biomarker.
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| 11. |
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| 12. |
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| 13. |
- Ericson, K, et al.
(författare)
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Lipidbestämning hos avlidna.
- 1996
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Ingår i: Hygiea. ; 105, s. 374-
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Recension (övrigt vetenskapligt/konstnärligt)
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| 14. |
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| 15. |
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| 16. |
- Ericson, K, et al.
(författare)
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Volume Determination of Intracranial Arteriovenous Malformations prior to Stereotactic Radiosurgical Treatment
- 1996
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Ingår i: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - : SAGE Publications. - 1591-0199. ; 2:4, s. 271-5
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Tidskriftsartikel (refereegranskat)abstract
- Exact dose planning for stereotactic radiosurgery was enabled in connection with diagnostic angiography or at the end of an endovascular procedure by simply placing a stereotactic localizing box onto the head of the patient while acquiring PA and lateral angiographic views. The fiducials engraved on the localizing box enabled the appropriate images to be scaled to the stereotactic space. Regular dose planning was then performed after estimating the size of the patient's head. A prediction of the chances of obliteration and the risks of complication could then be made immediately after the endovascular or diagnostic procedure, and further therapy could be selected much more confidently. This technique may also be used at centres without facilities for radiosurgical treatment if only the localizing box is available. The images may then be sent for evaluation to a unit with dose planning equipment. The technique is simple and involves little risk, significantly improving patient management. Digital subtraction angiography was used in this study. A correction algorithm was used to minimize the geometric distortion inherent to the digital technique.
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| 17. |
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| 18. |
- ERICSON, TEO, et al.
(författare)
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PI-NN COUPLING FROM HIGH-PRECISION NP CHARGE-EXCHANGE AT 162 MEV
- 1995
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMER INST PHYSICS. - 0031-9007. ; 75:6, s. 1046-1049
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Differential np cross sections for unpolarized neutrons of 162 MeV have been measured to high precision with particular attention to the absolute normalization. These data can be extrapolated precisely and model independently to the pion pole and give a p
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| 19. |
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| 21. |
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| 23. |
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| 25. |
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| 26. |
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| 27. |
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| 28. |
- Jensen-Urstad, M, et al.
(författare)
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Heart rate variability is related to leucocyte count in men and to blood lipoproteins in women in a healthy population of 35-year-old subjects.
- 1998
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Ingår i: Journal of Internal Medicine. - 0954-6820 .- 1365-2796. ; 243:1, s. 33-40
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To investigate if, in a healthy randomly-selected population of 35-year-old men and women, there already is a relation between decreased heart rate variability and conventional risk factors for cardiovascular disease. BACKGROUND: Analysis of heart rate variability (HRV) has been used for estimating tonic autonomic activity. HRV is reduced in patients with various cardiovascular diseases. If a decreased HRV is a late phenomenon in the progression of cardiovascular disease, or if it parallels or even precedes manifest disease is unknown. DESIGN: Spectral analysis of HRV was made from 24-hour ambulatory electrocardiograms in a randomised population of healthy 35-year-old men (n = 63) and women (n = 70). The different spectral indices of HRV were analysed against gender, leucocyte count (previously described as an independent risk factor for cardiovascular disease), blood lipoproteins, smoking, heredity, body mass index (BMI) and systolic blood pressure. SETTING: A research centre of general medicine and a university hospital. RESULTS: Mean heart rate was lower, total power (TP), very low frequency power (VLF) and low frequency power (LF) were higher in men than in women. In women TP, VLF and LF were negatively correlated to BMI, smoking, triglycerides and positively correlated to HDL cholesterol. TP and VLF were also negatively correlated to risk factor score. High frequency power (HF), a marker of parasympathetic activity, was positively related to HDL cholesterol. In men, at daytime, TP, VLF, LF and HF were negatively correlated to leucocyte count. TP, VLF and LF were also negatively correlated to triglycerides and VLF also to risk factor score. CONCLUSIONS: There are correlations between HRV and known risk factors for cardiovascular disease already in a healthy 35-year-old population. A novel observation is the relationship in men between leucocyte count and heart rate variability.
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| 29. |
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| 30. |
- Quintana, M, et al.
(författare)
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Heart rate variability as a means of assessing prognosis after acute myocardial infarction. A 3-year follow-up study.
- 1997
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Ingår i: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 18:5, s. 789-97
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: The present study evaluated the prognostic value of heart rate variability after acute myocardial infarction in comparison with other known risk factors. The cut-off points that maximized the hazards ratio were also explored. PATIENTS AND METHODS: Heart rate variability was assessed with 24 h ambulatory electrocardiography in 74 patients with acute myocardial infarction, 4 +/- 2 days after hospital admission and in 24 healthy controls. Patients were followed for 36 +/- 15 months. RESULTS: During follow-up, 18 patients died, nine suffered a non-fatal infarction and 20 underwent revascularization procedures. Heart rate variability was higher in survivors than in non-survivors (P = 0.005). This difference was found at higher statistical levels when comparing non-survivors vs controls (P = 0.0002). A similar statistically significant difference was also found between survivors vs controls (P = 0.04). Patients suffering non-fatal infarction and cardiac events (defined as death, non-fatal infarction or revascularization) had a lower heart rate variability than those without (P = 0.03 and P = 0.03, respectively). With multivariate regression analysis, decreased heart rate variability independently predicted mortality and death or non-fatal infarction. The presence of a left ventricular ejection fraction < 40% and a history of systemic hypertension were, however, stronger predictors. The cut-off points that maximized the hazards ratio using the Cox model differed from those reported by others. CONCLUSION: Decreased heart rate variability independently predicted poor prognosis after myocardial infarction. However, the cut-off points that should be used in clinical practice are still a matter for further investigation.
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| 31. |
- Rahm, J, et al.
(författare)
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np scattering measurements at 162 MeV and the pi NN coupling constant
- 1998
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Ingår i: PHYSICAL REVIEW C-NUCLEAR PHYSICS. - : AMERICAN PHYSICAL SOC. - 0556-2813. ; 57:3, s. 1077-1096
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The differential np scattering cross section has been measured at 162 MeV in the angular range theta(c.m.) = 72 degrees-180 degrees, using the neutron beam facility at The Svedberg Laboratory in Uppsala. Special attention was paid to the absolute normaliz
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| 32. |
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| 33. |
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| 34. |
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| 35. |
- Soderman, M, et al.
(författare)
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Stereotaxy in neuroradiology
- 1996
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Ingår i: RIVISTA DI NEURORADIOLOGIA. - 1120-9976. ; 9, s. 53-62
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 36. |
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| 37. |
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| 38. |
- Söderman, M, et al.
(författare)
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Acute-Sinus Thrombosis in a Child with Antibodies against Cardiolipins. Report of a Case Treated with Local Fibrinolysis
- 1996
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Ingår i: Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences. - : SAGE Publications. - 1591-0199. ; 2:2, s. 143-8
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Tidskriftsartikel (refereegranskat)abstract
- A case of thrombosis of the straight sinus and the left transverse sinus in an 11 year old boy is described. The patient had a history of slight trauma followed by infection of the upper airways and presented with severe impressive and expressive dysphasia and stupor.He was treated with in situ fibrinolysis. Despite successful local fibrinolysis and thrombectomy with a balloon catheter the patient rethrombosed his left transverse sinus several times and had a late thrombosis of his jugular vein.Nevertheless, flow in the left sigmoid sinus was facilitated and focal brain oedema was significantly reduced.Serum levels of antibodies against cardiolipins, associated with venous thrombosis, were elevated and interfered with reagents used for measuring the activated partial tromboplastin time, causing it to be falsely prolonged with subsequent underdosage of heparin. He was treated with oral anticoagulants for one year after the episode and recovered completely.
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