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Biomedical subjects

L Nilsson

Publications and source records attributed to L Nilsson.

At least 19 recordsLinked to original sources
PubMed2003

Respiratory variations in the reflection mode photoplethysmographic signal. Relationships to peripheral venous pressure.

Photoplethysmography (PPG) is a non-invasive optical way of measuring variations in blood volume and perfusion in the tissue, used in pulse oximetry for instance. Respiratory-induced intensity variations (RIIVs) in the PPG signal exist, but the physiological background is not fully understood. Respiration causes variations in the blood volume in the peripheral vascular bed. It was hypothesised that the filling of peripheral veins is one of the important factors involved. In 16 healthy subjects, the respiratory synchronous variations from a PPG reflection mode signal and the peripheral venous pressure (PVP) were recorded. Variations of tidal volume, respiratory rate and contribution from abdominal and thoracic muscles gave significant and similar amplitude changes in both RIIV and the respiratory variation of PVP (p<0.01). The highest amplitudes of both signals were found at the largest tidal volume, lowest respiratory rate and during mainly thoracic breathing, respectively. The coherence between PVP and RIIV signals was high, the median (quartile range) being 0.78 (0.42). Phase analysis showed that RIIV was usually leading PVP, but variations between subjects were large. Although respiratory-induced variations in PVP and PPG showed a close correlation in amplitude variation, a causal relationship between the signals could not be demonstrated.

Adult↗
PubMed2003

An unusual case of tumor thrombus in the inferior vena cava. A case report.

Adrenal cortical carcinoma (ACC) is a rare malignancy. Patients present either with a functional tumor or secondary to mass effect. In non-functioning tumors, the tumor size often exceeds 5 cm by the time of diagnosis, and tumor thrombus can occur. We report on a case of a small non-functioning ACC causing a large tumor thrombus in the inferior vena cava.

Adrenal Cortex Neoplasms↗
PubMed2002

Antibiotic prescription practices, consumption and bacterial resistance in a cross section of Swedish intensive care units.

BACKGROUND: The purpose of this work was to study usage of antibiotics, its possible determinants, and patterns of bacterial resistance in Swedish intensive care units (ICUs). METHODS: Prospectively collected data on species and antibiotic resistance of clinical isolates and antibiotic consumption specific to each ICU in 1999 were analyzed together with answers to a questionnaire. Antibiotic usage was measured as defined daily doses per 1000 occupied bed days (DDD1000). RESULTS: Data were obtained for 38 ICUs providing services to a population of approximately 6 million. The median antibiotic consumption was 1257 DDD1000 (range 584-2415) and correlated with the length of stay but not with the illness severity score or the ICU category. Antibiotic consumption was higher in the ICUs lacking bedside devices for hand disinfection (2193 vs. 1214 DDD1000, p=0.05). In the ICUs with a specialist in infectious diseases responsible for antibiotic treatment the consumption pattern was different only for use of glycopeptides (58% lower usage than in other ICUs: 26 vs. 11 DDD1000,P=0.02). Only 21% of the ICUs had a written guideline on the use of antibiotics, 57% received information on antibiotic usage at least every 3 months and 22% received aggregated resistance data annually. Clinically significant antimicrobial resistance was found among Enterbacter spp. to cephalosporins and among Enterococcus spp. to ampicillin. CONCLUSIONS: Availability of hand disinfection equipment at each bed and a specialist in infectious diseases responsible for antibiotic treatment were factors that correlated with lower antibiotic consumption in Swedish ICUs, whereas patient-related factors were not associated with antibiotic usage.

Adult↗
PubMed2002

Living situation, subjective quality of life and social network among individuals with schizophrenia living in community settings.

OBJECTIVE: To investigate the relationships between characteristics of the living situation in the community and subjective quality of life and social network among community-based individuals with schizophrenia. METHOD: A total of 418 individuals with schizophrenia from 10 sites were interviewed with regard to quality of life, psychopathology, social network and needs for care. Characteristics of the living situation investigated were: living alone or not, living with family or not, and having an independent or a sheltered housing situation. RESULTS: An independent housing situation was related to a better quality of life concerning living situation and living with the family to a better quality of life concerning family relations. An independent housing situation was associated with a better social network regarding availability and adequacy of emotional relations. CONCLUSION: People with schizophrenia with an independent housing situation have a better quality of life associated with more favorable perceptions of independence, influence, and privacy. Their social network is better irrespective of whether they live alone or not, or with family or not.

Activities of Daily Living↗
PubMed2002

Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet.

Epidemiological studies suggest that foods rich in flavonoids might reduce the risk of cardiovascular disease and cancer. The objective of the present study was to investigate the effect of green tea extract (GTE) used as a food antioxidant on markers of oxidative status after dietary depletion of flavonoids and catechins. The study was designed as a 2 x 3 weeks blinded human cross-over intervention study (eight smokers, eight non-smokers) with GTE corresponding to a daily intake of 18.6 mg catechins/d. The GTE was incorporated into meat patties and consumed with a strictly controlled diet otherwise low in flavonoids. GTE intervention increased plasma antioxidant capacity from 1.35 to 1.56 (P<0.02) in postprandially collected plasma, most prominently in smokers. The intervention did not significantly affect markers in fasting blood samples, including plasma or haemoglobin protein oxidation, plasma oxidation lagtime, or activities of the erythrocyte superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase. Neither were fasting plasma triacylglycerol, cholesterol, alpha-tocopherol, retinol, beta-carotene, or ascorbic acid affected by intervention. Urinary 8-oxo-deoxyguanosine excretion was also unaffected. Catechins from the extract were excreted into urine with a half-life of less than 2 h in accordance with the short-term effects on plasma antioxidant capacity. Since no long-term effects of GTE were observed, the study essentially served as a fruit and vegetables depletion study. The overall effect of the 10-week period without dietary fruits and vegetables was a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence.

Adult↗
PubMed2001

[Great geographic variations in the prevalence of asthma and allergy. International population studies to explain the associative factors].

During the 1990's the international variation in the prevalence of asthma and allergy was studied in young adults (European Community Respiratory Health Survey, ECRHS) and in children (International Study of Asthma and Allergy in Children, ISAAC). The prevalence of asthma and allergy was highest in the United Kingdom, North America, Australia and New Zealand, lower in the Baltic countries and very low in some of the poorest republics of the former USSR. Children that lived in the countryside during the first year of life had a lower prevalence of atopic disease as teenager while in adults farmers had the highest prevalence of occupational asthma. In both investigations a negative association was found between having pets as a child and atopic sensitisation. This association could, however, be related to selection mechanisms. In a three year follow-up of the Swedish part of the ECRHS the incidence of asthma was higher in smokers than non-smokers. Passive smoking was associated with respiratory symptoms in both children and adults. Follow-ups of both studies are being planned or performed. Further analyses of the geographic differences may explain the reason for the rapid increase of asthma and allergy in the Western world.

Adolescent↗
PubMed2001

MD simulations of homomorphous PNA, DNA, and RNA single strands: characterization and comparison of conformations and dynamics.

MD simulations of homomorphous single-stranded PNA, DNA, and RNA with the same base sequence have been performed in aqueous solvent. For each strand two separate simulations were performed starting from a (i) helical conformation and (ii) random coiled state. Comparisons of the simulations with the single-stranded helices (case i) show that the differences in the covalent nature of the backbones cause significant differences in the structural and dynamical properties of the strands. It is found that the PNA strand maintains its nice base-stacked initial helical structure throughout the 1.5-ns MD simulation at 300 K, while DNA/RNA show relatively larger fluctuations in the structures with a few local unstacking events during -ns MD simulation each. It seems that the weak physical coupling between the bases and the backbone in PNA causes a loss of correlation between the dynamics of the bases and the backbone compared to the DNA/RNA and helps maintain the base-stacked helical conformation. The global flexibility of a single-stranded PNA helix was also found to be lowest, while RNA appears to be the most flexible single-stranded helix. The sugar pucker of several nucleotides in single-stranded DNA and RNA was found to adopt both C2'-endo and C3'-endo conformations for significant times. This effect is more pronounced for single strands in completely coiled states. The simulations with single-stranded coils as the initial structure also indicate that a PNA can adopt a more compact globular structure, while DNA/RNA of the same size adopts a more extended coil structure. This allows even a short PNA in the coiled state to form a significantly stable nonsequentially base-stacked globular structure in solution. Due to the hydrophobic nature of the PNA backbone, it interacts with surrounding water rather weakly compared to DNA/RNA.

Base Sequence↗
PubMed2001

Structure, dynamics and electrostatics of the active site of glutaredoxin 3 from Escherichia coli: comparison with functionally related proteins.

The chemistry of active-site cysteine residues is central to the activity of thiol-disulfide oxidoreductases of the thioredoxin superfamily. In these reactions, a nucleophilic thiolate is required, but the associated pK(a) values differ vastly in the superfamily, from less than 4 in DsbA to greater than 7 in Trx. The factors that stabilize this thiolate are, however, not clearly established. The glutaredoxins (Grxs), which are members of this superfamily, contain a Cys-Pro-Tyr-Cys motif in their active site. In reduced Grxs, the pK(a) of the N-terminal active-site nucleophilic cysteine residue is lowered significantly, and the stabilization of the corresponding thiolate is expected to influence the redox potential of these enzymes. Here, we use a combination of long molecular dynamics (MD) simulations, pK(a) calculations, and experimental investigations to derive the structure and dynamics of the reduced active site from Escherichia coli Grx3, and investigate the factors that stabilize the thiolate. Several different MD simulations converged toward a consensus conformation for the active-site cysteine residues (Cys11 and Cys14), after a number of local conformational changes. Key features of the model were tested experimentally by measurement of NMR scalar coupling constants, and determination of pK(a) values of selected residues. The pK(a) values of the Grx3 active-site residues were calculated during the MD simulations, and support the underlying structural model. The structure of Grx3, in combination with the pK(a) calculations, indicate that the pK(a) of the N-terminal active-site cysteine residue in Grx3 is intermediate between that of its counterpart in DsbA and Trx. The pK(a) values in best agreement with experiment are obtained with a low (<4) protein dielectric constant. The calculated pK(a) values fluctuate significantly in response to protein dynamics, which underscores the importance of the details of the underlying structures when calculating pK(a) values. The thiolate of Cys11 is stabilized primarily by direct hydrogen bonding with the amide protons of Tyr13 and Cys14 and the thiol proton of Cys14, rather than by long-range interactions from charged groups or from a helix macrodipole. From the comparison of reduced Grx3 with other members of the thioredoxin superfamily, a unifying theme for the structural basis of thiol pK(a) differences in this superfamily begins to emerge.

Bacterial Proteins↗
PubMed2001

[Consumption of psychopharmaceuticals in residential facilities for the elderly. Evaluation of the extent, indications and effects].

Previous studies have shown a high level of consumption of psychopharmacological drugs in nursing homes. A questionnaire study in Kronoberg County in the autumn of 1998 investigated treatment with psychopharmacological drugs at ten nursing homes with a total of 405 care recipients. The questionnaire included questions about the extent of treatment, indications, duration of treatment and evaluation routines. Some 59% of the recipients, with a variation of 48-73% in different homes, were in continuous treatment with psychopharmacological drugs. Disturbances of sleep, depression and anxiety accounted for 79% of all indications. For 84%, treatment duration was not time-limited ("until further notice"). Assessments by the care staff were the most common evaluation procedure. In only 43% of cases were patients' self-evaluations heeded. Neuroleptics were probably overused, often with indications other than psychotic symptoms. Repeated treatment evaluations involving different categories of staff are important if excessive medication is to be avoided.

Aged↗
PubMed2001

Thoracic epidural anesthesia does not influence the occurrence of postoperative sustained atrial fibrillation.

BACKGROUND: To evaluate whether thoracic epidural anesthesia (TEA) can reduce the incidence of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). METHODS: Forty-one patients undergoing CABG were treated with TEA intraoperatively and postoperatively. Another 80 patients served as the control group. The sympathetic and parasympathetic activities were evaluated by analysis of neuropeptides, catecholamines and heart rate variability (HRV), preoperatively and postoperatively. RESULTS: Postoperative AF occurred in 31.7% of the TEA-treated patients and in 36.3% of the untreated patients (p = 0.77). TEA significantly suppressed sympathetic activity, as indicated by a less pronounced increase of norepinephrine and epinephrine (p = 0.03, p = 0.02) and a significant decrease of neuropeptide Y (p = 0.01) postoperatively in TEA-treated patients compared to untreated patients. The HRV variable expressing sympathetic activity was significantly lower and the postoperative increase in heart rate was significantly less in the TEA group than in the control group after surgery (p = 0.01, p < 0.001). Among patients developing AF, the maximal number of supraventricular premature beats per minute increased significantly in untreated patients postoperatively but remained unchanged in TEA-treated patients (p = 0.004 versus p = 0.86). CONCLUSIONS: TEA has no effect on the incidence of postoperative sustained AF, despite a significant reduction in sympathetic activity.

Aged↗
PubMed2001

A triglyceride-rich fat emulsion and free fatty acids but not very low density lipoproteins impair endothelium-dependent vasorelaxation.

OBJECTIVE: To investigate the effects of triglycerides and free fatty acids on endothelium-dependent and endothelium-independent vasorelaxation. METHODS: Femoral arterial rings from rats were studied in organ baths. The vascular segments were constricted with phenylephrine after 20 min of preincubation with the triglyceride-rich fat emulsion Intralipid, free fatty acids (16:0, 18:1, 18:3) bound to bovine serum albumin, or very low density lipoproteins. Endothelium-dependent and endothelium-independent relaxations were determined after administration of acetylcholine and nitric oxide donors, respectively. RESULTS: Preincubation with Intralipid caused a concentration-dependent impairment of endothelium-dependent but not endothelium-independent relaxation. Very low density lipoproteins did not affect vascular function. All free fatty acids impaired endothelium-dependent relaxation, whereas endothelium-independent relaxation was unaffected. Administration of the antioxidant vitamin C partly reversed the impairment of the endothelium-dependent relaxation induced by Intralipid and free fatty acids. CONCLUSIONS: The present study demonstrates that the triglyceride-rich fat emulsion Intralipid and individual FFAs impair endothelium-dependent relaxation of arterial rings from rat, whereas triglycerides in the form of VLDL do not affect endothelial function. The finding that the antioxidant vitamin C partly reverses this impairment indicates the involvement of oxidative mechanisms.

Acetylcholine↗
PubMed2001

Low peripheral blood levels of the immunosuppressive cytokine interleukin 10 (IL-10) at the start of gonadotrophin stimulation indicates increased risk for development of ovarian hyperstimulation syndrome (OHSS).

Our hypothesis was that patients developing ovarian hyperstimulation syndrome (OHSS) might have a disturbed responsiveness or delayed activation of the immunosuppresive cytokine system. In a prospective cohort study, women (n=428) undergoing in vitro fertilisation (IVF) treatment were subjected to repeated blood sampling and collection of clinical data. Fifteen patients, who developed severe OHSS, were compared with matched (age, follicle numbers, pregnancy) control patients. Samples of serum and plasma were collected throughout the stimulation and up to 7 days after embryo transfer as well as during hospitalisation for OHSS. Levels of IL-4, IL-10, IL-13, oestradiol and progesterone were measured. Significantly lower levels of IL-10 were seen at the start of gonadotrophin stimulation in OHSS patients, with an increase seen after the development of OHSS. In these OHSS patients, a negative correlation between IL-10 levels and number of follicles at time of aspiration existed, but there were no correlations between steroid and IL-10 levels. Levels of IL-13 and IL-4 were low in both groups and did not change during stimulation. The lower levels of IL-10 at start of stimulation in OHSS patients, as compared with controls, may be of pathophysiological importance by allowing for an enhanced Th-1 type immune response during gonadotrophin stimulation and thereby increased and generalised inflammation. The increase in IL-10 after development of OHSS indicates that IL-10 at that time is induced in a systemic attempt to suppress the inflammation of OHSS.

Cohort Studies↗
PubMed2001

Plasma levels of free vascular endothelial growth factor(165) (VEGF(165)) are not elevated during gonadotropin stimulation in in vitro fertilization (IVF) patients developing ovarian hyperstimulation syndrome (OHSS): results of a prospective cohort study with matched controls.

OBJECTIVE: To evaluate whether differences in plasma vascular endothelial growth factor(165) (VEGF(165)) concentrations exist during gonadotropin stimulation in IVF patients developing severe ovarian hyperstimulation syndrome (OHSS) compared to matched controls. STUDY DESIGN: Prospective cohort study with comparison of 15 OHSS cases with 30 matched (age, follicle numbers, pregnancy) controls. Unpaired students t-test was used to evaluate differences between the OHSS and control group and correlations were calculated with Pearson's test. RESULT(S): Plasma levels of VEGF(165), at four time-points from start of gonadotropin stimulation to embryo transfer (ET), were compared and related to steroid levels and ultrasound data. There were no differences between OHSS and control patients in plasma VEGF(165) levels at any of the four time points, which were compared. The mean levels were between 53--83 pg ml(-1) and 64--83 pg ml(-1) in the OHSS and control group, respectively. Positive correlations existed between total number of follicles, number of large (>15 mm) follicles and VEGF(165) at day of oocyte aspiration and between VEGF(165) and progesterone at ET in the control group, but not in the OHSS group. CONCLUSION(S): Patients developing OHSS do not have raised plasma VEGF(165) levels during gonadotropin stimulation. The lack of positive correlation between VEGF(165) levels and follicle numbers/progesterone in the OHSS group, suggests a disruption in OHSS of the normal controlled follicular VEGF expression.

Adult↗
PubMed2001

Effects of staurosporine, U-73122, wortmannin, 4-hydroxynonenal and sodium azide upon the release of secreted beta-amyloid precursor protein from human platelets in response to thrombin stimulation.

In the present study, the release of secreted beta-amyloid precursor protein (AbetaPPs) in response to thrombin stimulation in platelets has been investigated. Incubation of platelets with thrombin produced a concentration-dependent release of AbetaPPs with a concomitant reduction in the AbetaPP remaining in the lysates. The response to thrombin was not affected by pretreatment for 15 min with the phospholipase C inhibitor U-73122, with the protein kinase C inhibitor staurosporine, or with hydrogen peroxide (which at the concentrations used affects the phosphoinositide signalling system in human platelets). In contrast, pretreatment with wortmannin and sodium azide reduced the responses to thrombin. These data would suggest that thrombin may cause the release of AbetaPPs from human platelets via an activation of a phospholipase C-independent pathway. Thrombin-stimulated AbetaPPs release was also reduced by 4-hydroxynonenal. This finding, if it is a phenomenon also found for CNS cells, could be of relevance to the pathogenesis of Alzheimer's disease, given that an accumulation of 4-hydroxynonenal is found in this disease.

Aldehydes↗
PubMed2001

Do early childhood immunizations influence the development of atopy and do they cause allergic reactions?

Concerns about allergic side-effects of vaccines and about a possible promotion of allergic diseases contribute to incomplete vaccination rates in childhood. This article reviews the current understanding of these issues. There is evidence that pertussis and diphtheria/tetanus antigens elicit immunoglobulin E (IgE) antibody formation as part of the immune response. In murine models, pertussis toxin is an effective adjuvant for IgE formation against simultaneously administered antigens. In children, however, sensitization to unrelated antigens or development of allergic diseases do not seem to be augmented. In contrast, bacille Calmette-Guérin (BCG) and measles vaccination have been proposed as suppressors of allergy because of their T helper 1 (Th1)-fostering properties. In the murine system, BCG inhibits allergic sensitization and airway hyper-reactivity. Some epidemiological studies in humans suggest an inhibitory effect of tuberculosis on allergy. BCG vaccination in children, however, has no or merely a marginal suppressive effect on atopy. Other vaccine components such as egg proteins, gelatin, and antibiotics are a potential hazard to children with severe clinical reactions to these allergens. These rare children should be vaccinated under special precautions. In conclusion, vaccination programs do not explain the increasing prevalence of allergic diseases, but individual children may uncommonly develop an allergic reaction to a vaccine. The risks of not vaccinating children, however, far outweigh the risk for allergy. Therefore, childhood vaccination remains an essential part of child health programs and should not be withheld, even from children predisposed for allergy.

Adolescent↗
PubMed2001

Comparison of key worker and patient assessment of needs in schizophrenic patients living in the community: a Nordic multicentre study.

OBJECTIVE: The present study is part of a Nordic multicentre study investigating the life and care situation of community samples of schizophrenic patients. The specific aim of the present part of the study was to examine the agreement between patients and their key worker concerning the presence of met and unmet needs in a number of life domains, and help or support given in these domains. METHOD: The comparisons were based on 300 matched pairs of assessments of need using the Camberwell Assessment of Need interview. RESULTS: The results showed that key workers identified slightly more needs, 6.17 vs. 5.76, a significant difference. There was a moderate or better agreement on the presence of a need in 17 of 22 life domains investigated, but in only 11 life domains concerning the presence of an unmet need. Disagreement concerning whether the patient was given the right kind of help or support was even more substantial. CONCLUSION: It is concluded that key workers and patients disagree particularly concerning unmet needs and that this is potentially related to a number of factors associated with the key worker and patient. It is also concluded that further research is needed to increase the knowledge concerning the sources of this disagreement if need assessment is to become a valid basis for service planning and individual treatment planning.

Adult↗
PubMed2001

Wheezing in relation to atopy and environmental factors in Estonian and Swedish schoolchildren.

BACKGROUND: The prevalence of asthma and allergic diseases is significantly lower in post socialist Eastern Europe than in Western industrialized countries. The reason for this difference is largely unknown. Different types of childhood wheezing could be related to different risk factors. OBJECTIVE: To compare the prevalence of respiratory symptoms, asthma and atopic diseases among Estonian and Swedish schoolchildren and to evaluate characteristics for wheezing in the two countries. METHODS: In a prevalence study, population-based random samples of 10-11-year-old schoolchildren in Tallinn (n = 979), Estonia and in Linköping (n = 911) and Ostersund (n = 1197), Sweden were studied by a parental questionnaire and skin prick tests (SPT). All 275 children with wheeze in the past 12 months and 710 randomly selected controls within the original cohorts were invited to a case-control study involving a parental questionnaire, examination for flexural dermatitis and bronchial challenge with hypertonic saline. The study adhered to the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. RESULTS: The prevalence of current wheezing was similar (8-10%) in the three centres, while diagnosed asthma and atopic symptoms were more common in Sweden and cold-related respiratory symptoms were more prevalent in Estonia. Frequent wheezing was more common in Sweden than in Estonia (but significantly so only in Ostersund). Wheezing children in Sweden had a high rate of positive SPT (49% in Linköping and 58% in Ostersund) bronchial hyper-responsiveness (BHR) (48% in Linköping and Ostersund) and anti-asthmatic treatment (63% in Linköping and 81% in Ostersund). In Estonia, the proportion of wheezing children with positive SPT, BHR and anti-asthmatic treatment was only 26%, 13% and 17%, respectively. Domestic crowding was inversely related to wheezing in one of the study areas (Ostersund). The mean baseline forced expiratory volume in one second (FEV1) was higher in Estonia than in Sweden, both in wheezing and non-wheezing children. CONCLUSIONS: Our study suggested that although wheezing symptoms were equally common in Estonia and Sweden, they were less severe in Estonia. More frequent symptoms and a high rate of atopy, BHR and anti-asthmatic medication characterized wheezing children in Sweden. In contrast, BHR, atopy and medication were uncommon among wheezing children in Estonia.

Bronchial Hyperreactivity↗