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Biomedical subjects

Anders Larsson

Publications and source records attributed to Anders Larsson.

At least 55 records · Page 3Linked to original sources

Inflammatory activity: capillary electrophoresis provides more information than erythrocyte sedimentation rate.

BACKGROUND: A new automated multicapillary zone electrophoresis instrument with improved resolution buffer (Capillarys with HR buffer, SEBIA, Paris, France) for analysis of human plasma proteins was compared with erythrocyte sedimentation rate (ESR). ESR determinations have been performed for more than eighty years and it is still one of the most frequently used laboratory tests, mainly to monitor the inflammatory response and as a tumour marker. METHODS: We studied the relationships between ESR, capillary electrophoresis and nephelometric determination of fibrinogen and albumin in 503 consecutive patient samples. The samples were analyzed on the Capillarys. The albumin concentration from the nephelometric determination was used for quantification of the individual peaks in the capillary electrophoresis electropherogram. RESULTS: We found no significant correlation between presence or size of M-components and ESR. There were moderate to strong correlations between ESR, fibrinogen and capillary electrophoretic determination of alpha1-antitrypsin, alpha1-acid glycoprotein or haptoglobin for the detection of acute phase response. CONCLUSIONS: We suggest that ESR could be replaced by capillary electrophoresis for the assessment of inflammatory conditions and to detect M-components.

Acute-Phase Proteins↗

Cystatin C: a novel predictor of outcome in suspected or confirmed non-ST-elevation acute coronary syndrome.

BACKGROUND: Patients with suspected or confirmed non-ST-elevation acute coronary syndrome (ACS) constitute a large and heterogeneous group. Measurements of renal function such as serum creatinine and estimation of creatinine clearance carry independent prognostic information in this population. Cystatin C is a new and better marker of renal function than creatinine. The aim was therefore to evaluate the prognostic value of cystatin C in this population. METHODS AND RESULTS: Cystatin C was analyzed on admission in 726 patients admitted because of symptoms suggestive of an acute coronary syndrome and no ST-segment elevations. Patients were followed up with regard to death and myocardial infarction for a median of 40 and 6 months, respectively. The median cystatin C level was 1.00 mg/L (25th to 75th percentile, 0.83 to 1.24 mg/L). The risk of death during follow-up increased with increasing levels of cystatin C. In the group with non-ST-elevation ACS, patients in the second, third, and fourth quartiles had a relative risk of subsequent death of 1.8 (95% CI, 0.6 to 5.3), 3.2 (95% CI, 1.2 to 8.5), and 11.7 (95% CI, 4.7 to 29.3) compared with the lowest quartile. In Cox regression models including well-known predictors of outcome, cystatin C level was independently associated with mortality but not with the risk of subsequent myocardial infarction. In a comparison of the markers of renal function in receiver-operating curve analyses, cystatin C had the best ability to discriminate between survivors and nonsurvivors. CONCLUSIONS: A single measurement of cystatin C will substantially improve the early risk stratification of patients with suspected or confirmed non-ST-elevation ACS.

Acute Disease↗

The role of circulating anti-p53 antibodies in patients with advanced non-small cell lung cancer and their correlation to clinical parameters and survival.

BACKGROUND: Lung cancer causes approximately one million deaths each year worldwide and protein p53 has been shown to be involved in the intricate processes regulating response to radiation and/or chemotherapeutic treatment. Consequently, since antibodies against p53 (anti-p53 antibodies) are associated with mutations within the p53 gene it seems likely that these antibodies could, hypothetically, be correlated with prognosis. METHODS: Serum samples from patients with non-small cell lung cancer (NSCLC) admitted to the Department of Oncology, University Hospital, Uppsala, Sweden, during 1983-1996 were studied. Anti-p53 abs were measured using a sandwich ELISA (Dianova, Hamburg, Germany). RESULTS: The present study included 84 patients with stage IIIA-IV (advanced NSCLC). At least three serum samples from each patient were collected and altogether 529 serum samples were analysed for the presence of anti-p53 antibodies. The median value of anti-p53 antibodies was 0.06 (range 0 - 139.8). Seventeen percent of investigated NSCLC first serum samples (n = 84) expressed elevated levels of anti-p53 antibodies. Anti-p53 antibodies were not correlated to tumour volume or platelets. Survival analysis showed that anti-p53 antibodies were not associated with survival as revealed by univariate analysis (p = 0.29). However, patients with adenocarcinoma had a significantly poorer survival if they expressed anti-p53 antibodies (p = 0.01), whereas this was not found for patients with squamous cell carcinoma (p = 0.13). In patients where the blood samples were collected during radiation therapy, a statistically significant correlation towards poorer survival was found (p = 0.05) when elevated anti-p53 antibodies levels were present. No correlations to survival were found for serum samples collected prior to radiation therapy, during chemotherapy, or during follow-up. When anti-p53 antibodies were measured continuously, no increase in median anti-p53 values was observed the closer the individual patient come to death. CONCLUSION: The result of the present retrospective study indicates that anti-p53 antibodies are not suitable for predictions concerning selection of patients with a more favourable outcome. Further prospective studies are, though, needed to fully elucidate this issue.

Adenocarcinoma↗

Novel non-coding RNAs in Dictyostelium discoideum and their expression during development.

The quest for non-coding RNAs (ncRNAs) in the last few years has revealed a surprisingly large number of small RNAs belonging to previously known as well as entirely novel classes. Computational and experimental approaches have uncovered new ncRNAs in all kingdoms of life. In this work, we used a shotgun cloning approach to construct full-length cDNA libraries of small RNAs from the eukaryotic model organism Dictyostelium discoideum. Interestingly, two entirely novel classes of RNAs were identified of which one is developmentally regulated. The RNAs within each class share conserved 5'- and 3'-termini that can potentially form stem structures. RNAs of both classes show predominantly cytoplasmic localization. In addition, based on conserved structure and/or sequence motifs, several of the identified ncRNAs could be divided into classes known from other organisms, e.g. 18 small nucleolar RNA candidates (17 box C/D, of which a few are developmentally regulated, and one box H/ACA). Two ncRNAs showed a high degree of similarity to the small nuclear U2 RNA and signal recognition particle RNA (SRP RNA), respectively. Furthermore, the majority of the regions upstream of the sequences encoding the isolated RNAs share conserved motifs that may constitute new promoter elements.

Animals↗

Incomplete protection by prophylactic surfactant against the adverse effects of large lung inflations at birth in immature lambs.

OBJECTIVE: To investigate whether preceding surfactant instillation prevents the harmful effect of large lung inflations at birth in immature lambs, and, if not, to find out for how long the immature lung remains sensitive to large inflations. DESIGN: In an exploratory study, 12 preterm lambs given surfactant at birth were randomized to receive five large lung inflations at four different times: at birth just before or immediately after surfactant treatment; at 10 min; or at 60 min of age. In a confirmatory study, 10 pairs of preterm lamb twins were all given surfactant before the first breath. One lamb in each pair was randomised to receive large lung inflations immediately after surfactant while the other twin underwent similar inflations at 10-15 min of age. SETTING: Animal laboratory. EXPERIMENTAL ANIMALS: Anaesthetized lambs delivered by cesarean section at a gestational age of 127 days. INTERVENTIONS: Surfactant supplementation at birth. Five sustained lung inflations of 16 ml/kg at different times in relation to surfactant instillation. Pressure-limited mechanical ventilation for 4 h. MEASUREMENTS AND RESULTS: The response to surfactant was assessed by ventilator settings, lung mechanics and lung histology. Preceding surfactant supplementation did not prevent the adverse effect of large lung inflations at birth on ventilatory efficiency and lung mechanics, but seemed to protect against severe lung injury. No adverse effect was seen from large lung inflations given at 10 min of age or later. CONCLUSION: Prophylactic surfactant supplementation does not fully protect against the harmful effect of large lung inflations during a short sensitive period immediately after birth.

Age Factors↗

Association of type 2 diabetes with cyclooxygenase-mediated inflammation and oxidative stress in an elderly population.

BACKGROUND: Involvement of cyclooxygenase (COX)-mediated inflammation in type 2 diabetes has not been studied, and the association between cytokine-mediated inflammation and diabetes is not fully clarified. METHODS AND RESULTS: 15-Keto-dihydro-prostaglandin F2alpha (a metabolite of prostaglandin F2alpha and an indicator of COX-mediated inflammation), high-sensitivity C-reactive protein (CRP), serum amyloid protein A (SAA), 8-iso-PGF2alpha (a nonenzymatic, free radical product of arachidonic acid and an indicator of oxidative stress), and alpha-tocopherol were measured in a population-based sample of 77-year-old men (n=765), in which 112 men had type 2 diabetes. The inflammatory indicators were increased in men with diabetes (urinary 15-keto-dihydro-PGF2alpha, P<0.001, CRP and SAA, P<0.05). However, when adjusted for body mass index, waist circumference, or fasting insulin, no association was found between diabetes and CRP or SAA. The oxidative stress indicator 8-iso-PGF2alpha in urine was increased (P<0.01) in men with diabetes. Patients who were newly diagnosed with diabetes (<7 years since diagnosis) had increased urinary 15-keto-dihydro-PGF2alpha and decreased alpha-tocopherol, but 8-iso-PGF2alpha was unaltered. CONCLUSIONS: This is the first study to show that type 2 diabetes in elderly men is related to COX-mediated inflammation, reflected by enhanced prostaglandin formation. The high levels of cytokine-mediated acute-phase proteins observed in men with diabetes appear to be related to obesity and increased fasting insulin. The results further suggest that the appearance of chronic inflammation is an early process in the pathogenesis of diabetes, whereas oxidative injury may be a later process, possibly related to inflammation.

Aged↗

Biochemical indicators of cardiac and renal function in a healthy elderly population.

OBJECTIVES: To examine the distributions of NT-proBNP and cystatin C and their relation to age, gender, and other physiological factors in an apparently healthy elderly population. METHOD: NT-proBNP and cystatin C were analyzed in 407 and 408 healthy individuals, median age: 65 (range 40-76). RESULTS: Increasing age, female gender and CRP were independently associated to higher NT-proBNP levels. Age, body mass index, and CRP level were independently associated to the cystatin C level. In women and men, < or =65 years, the 97.5th percentile value for NT-proBNP was 268 ng/l and 184 ng/l, in those older, 391 ng/l and 269 ng/l. For those < or =65 years the 97.5th percentile value for cystatin C was 1.12 mg/l, and for those older 1.21 mg/l. CONCLUSION: In a healthy elderly population, NT-proBNP is influenced by age and gender, whereas cystatin C is influenced by age but not by gender. Both markers seem to be associated to the CRP level.

Age Factors↗

Vascular endothelial growth factor (VEGF)--a possible mediator of inflammation and mucosal permeability in patients with collagenous colitis.

Patients with collagenous colitis have watery diarrhea and histopathologically thickened collagen layer with discrete signs of mucosal inflammation. Vascular endothelial growth factor (VEGF) is a potent angiogenic, mitogenic, permeability, and fibrosis enhancing peptide and it was studied by segmental perfusion and immunohistochemistry in patients and controls. The concentrations of VEGF were significantly increased in perfusates from both the descending colon and the rectum in patients compared to controls but this difference was not found in serum. Immunohistochemical staining showed expression of VEGF within colon epithelial cells, inflammatory cells, and fibroblasts in the lamina propria. The intensity of staining in the surface epithelium was not different between patients and controls but in the lamina propria the intensity was significantly higher among controls. Patients with collagenous colitis have increased colorectal mucosal secretion of VEGF, which may lead to albumin leakage and promote fibrosis with deposition of collagen.

Adult↗

Acute hyperinsulinemia restrains endotoxin-induced systemic inflammatory response: an experimental study in a porcine model.

BACKGROUND: Intensive insulin therapy in critically ill patients reduces morbidity and mortality. The current study elucidates whether acute hyperinsulinemia per se could attenuate the systemic cytokine response and improve neutrophil function during endotoxin (lipopolysaccharide)-induced systemic inflammation in a porcine model. METHODS: Pigs were anesthetized, mechanically ventilated, randomized into four groups, and followed for 570 min: group 1 (anesthesia solely, n = 10), group 2 (hyperinsulinemic euglycemic clamp [HEC], n = 9), group 3 (lipopolysaccharide, n = 10), group 4 (lipopolysaccharide-HEC, n = 9). Groups 3 and 4 were given a 180-min infusion of lipopolysaccharide (total, 10 microg/kg). Groups 2 and 4 were clamped (p-glucose: 5 mM/l, insulin 0.6 mU.kg(-1).min(-1)) throughout the study period. Changes in pulmonary and hemodynamic function, circulating cytokines, free fatty acids, glucagon, and neutrophil chemotaxis were monitored. RESULTS: Tumor necrosis factor alpha and interleukin 6 were significantly reduced in the lipopolysaccharide-HEC group compared with the lipopolysaccharide group (both P = 0.04). In the lipopolysaccharide-HEC group, the glucagon response was diminished compared with the lipopolysaccharide group (P < 0.05). Serum free fatty acid concentrations were decreased in animals exposed to HEC. Animals receiving lipopolysaccharide showed an increase in pulmonary pressure (P < 0.001), but otherwise, there were no major changes in pulmonary or hemodynamic function. Neutrophil function was impaired after lipopolysaccharide administration. CONCLUSION: Hyperinsulinemia concomitant with normoglycemia reduces plasma concentrations of tumor necrosis factor alpha and the catabolic hormone glucagon in lipopolysaccharide-induced systemic inflammation in pigs. The finding strongly supports the role of insulin as an antiinflammatory hormone. Whether the effect to some extent operates via a reduced free fatty acid concentration is unsettled.

Acute Disease↗

Serum semicarbazide-sensitive amine oxidase (SSAO) activity correlates with VEGF in non-small-cell lung cancer patients.

Semicarbazide-sensitive amine oxidase (SSAO) is an enzyme associated with vascular systems in mammals. SSAO catalyzes the deamination of primary monoamines and has been suggested to be a risk factor in vascular disorders, e.g., diabetic vascular complications. The primary aim of the present study was to investigate if serum SSAO activity is associated with clinical parameters in non-small cell lung cancer (NSCLC) patients. Secondary aims were to investigate if there is a correlation between SSAO activity and the angiogenic factors vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF).Thirty-three patients donated 231 serum samples. Detectable levels of bFGF, VEGF, and SSAO were observed in all patients. Serum SSAO activity was not statistically associated with survival (p = 0.35). A highly significant statistical correlation was found between SSAO activity and VEGF (p < 0.0001). No significant correlation between SSAO and bFGF was observed. We conclude that SSAO was not associated with survival in patients with NSCLC. However, a strong correlation between serum SSAO activity and the angiogenic factor VEGF was found that might implicate new aspects of the mechanisms controlling angiogenesis.

Adenocarcinoma↗

Analysis of inflammatory response in human plasma samples by an automated multicapillary electrophoresis system.

A new automated multicapillary zone electrophoresis instrument with a new high-resolution (HR) buffer (Capillarys with HR buffer) for analysis of human plasma proteins was evaluated. Albumin, alpha(1)-antitrypsin, alpha(1)-acid glycoprotein, haptoglobin, fibrinogen, immunoglobulin (Ig)A, IgG and IgM were determined nephelometrically in 200 patient plasma samples. The same samples were then analyzed on the Capillarys system (Sebia, Paris, France). The albumin concentration from the nephelometric determination was used for quantification of the individual peaks in the capillary electrophoresis (CE) electropherogram. There was strong linear correlation between the nephelometric and electrophoretic determination of alpha(1)-antitrypsin (R(2) = 0.906), alpha(1)-acid glycoprotein (R(2) =0.894) and haptoglobin (R(2) = 0.913). There was also good correlation between the two determinations of gamma-globulins (R(2) = 0.883), while the correlation was weaker for fibrinogen (R(2) = 0.377). The Capillarys instrument is a reliable system for plasma protein analysis, combining the advantages of full automation, good analytical performance and high throughput. The HR buffer in combination with albumin quantification allows the simultaneous quantification of inflammatory markers in plasma samples without the need for nephelometric determination of these proteins.

Albumins↗

Cystatin C vs creatinine as markers of renal function in patients on digoxin treatment.

BACKGROUND: The kidney function is a major determinant of the serum concentration of digoxin as this drug is mainly eliminated unchanged through the kidneys. Since digoxin is widely prescribed among the elderly, and the glomerular filtration rate (GFR) declines with age, it is important that the clinician takes the patient's GFR into account when prescribing digoxin. Serum cystatin C has been suggested to be superior to creatinine for estimation of GFR, which may have relevance for the optimization of treatment with digoxin. METHODS: To evaluate which of the two GFR markers serum creatinine and serum cystatin C that best correlates with serum digoxin, we compared the serum levels of digoxin with the serum levels of creatinine and cystatin C in 149 patients on therapeutic drug monitoring of digoxin at our hospital. RESULTS: Overall, there was a stronger correlation between serum digoxin concentrations and cystatin C (p=0.00001) as compared to creatinine (p= 0.00003). Interestingly, of the patients with a serum digoxin concentration > or = 1.5 nmol/L, 29% had a serum creatinine level within normal limits, as compared to 20% with normal cystatin C levels. CONCLUSIONS: In this study, serum cystatin C correlated better to serum digoxin than did serum creatinine. With improved GFR monitoring, digoxin concentrations should be better controlled.

Aged↗

Design requirements for ubiquitous computing environments for healthcare professionals.

Ubiquitous computing environments can support clinical administrative routines in new ways. The aim of such computing approaches is to enhance routine physical work, thus it is important to identify specific design requirements. We studied healthcare professionals in an emergency room and developed the computer-augmented environment NOSTOS to support teamwork in that setting. NOSTOS uses digital pens and paper-based media as the primary input interface for data capture and as a means of controlling the system. NOSTOS also includes a digital desk, walk-up displays, and sensor technology that allow the system to track documents and activities in the workplace. We propose a set of requirements and discuss the value of tangible user interfaces for healthcare personnel. Our results suggest that the key requirements are flexibility in terms of system usage and seamless integration between digital and physical components. We also discuss how ubiquitous computing approaches like NOSTOS can be beneficial in the medical workplace.

Computer Graphics↗

Endotoxin neutralization and anti-inflammatory effects of tobramycin and ceftazidime in porcine endotoxin shock.

INTRODUCTION: Antibiotics used for treatment of severe bacterial infections have been shown to exert effects on the inflammatory response in addition to their antibacterial effects. The aim of the present study was to investigate whether the biological effects of endotoxin in a porcine model could be neutralized by tobramycin, and whether tobramycin or ceftazidime was able to modulate the inflammatory response. METHOD: Thirteen piglets were subjected to endotoxin infusion at an initial rate of 4 microgram/kg per hour, which was reduced to 1 microgram/kg per hour after 30 min. Before endotoxin infusion, the animals received saline (n = 4), ceftazidime (n = 5), or tobramycin (n = 4) at clinically relevant doses. Physiological parameters were measured and blood samples were taken hourly for 6 hours for analysis of tumour necrosis factor-alpha, IL-6 and endotoxin concentrations. RESULTS: All of the animals exhibited physiological signs of severe sepsis without major differences between the groups. Plasma endotoxin concentration was stable after 1 hour. There were no differences in endotoxin concentration or initial tumour necrosis factor-alpha and IL-6 concentrations between the groups. At 6 hours the IL-6 concentration was significantly lower in the ceftazidime group than in the saline group (P < 0.05), and in both the ceftazidime and the tobramycin groups there were significantly greater reductions from peak values (P < 0.05). CONCLUSION: There was no neutralization of the biological effects of endotoxin in this porcine model. However, our data indicate a possible anti-inflammatory effect exerted by both ceftazidime and tobramycin, which manifested as a significantly greater reduction in IL-6 in comparison with the untreated group.

Animals↗

Increased serum and cerebrospinal fluid FGF-2 levels in amyotrophic lateral sclerosis.

Lack of growth factors and hypoxia are two recent hypotheses about mechanisms underlying motor neuron death in amyotrophic lateral sclerosis. With this background, serum from 15 patients with amyotrophic lateral sclerosis and 15 controls, and CSF from 15 patients and 10 controls were analysed for fibroblast growth factor 2 (FGF-2) using an immunoassay. Serum FGF-2 levels were higher in the patient group than in the control group. FGF-2 was detected in CSF in 11/15 patients, but in none of the 10 control subjects. There were no correlations between age, duration of disease or clinical rating and FGF-2 levels. The findings indicate that FGF-2 is involved in the pathophysiological chain of events in this disorder.

Adult↗

Multifunctional gratings for surface-emitting lasers: design and implementation.

We experimentally demonstrate the use of two different multifunctional grating couplers in surface-emitting lasers for improved beam quality and advanced beam profiles. The lasers used for the demonstration are grating-based unstable resonator lasers, each with a grating coupler for surface emission and beam shaping. The new design method, described in detail, allows for simultaneous optimization of arbitrary feedback and outcoupling characteristics of the grating coupler. The first coupler is designed to reduce feedback to the resonator that would otherwise disturb the operation of the laser and lower the beam quality and to produce an output beam focused to four spots. The second coupler is designed to provide the feedback needed to support the unstable resonator, eliminating one feedback grating, and simultaneously focus the output beam to a single spot. As far as we know, this is the first time such multifunctional couplers are used in grating-coupled surface-emitting lasers. The couplers provide near-diffraction-limited spots that are a considerable improvement compared with previous lasers with no feedback control in the couplers.

Journal Article↗