Search PubMed⌕ Search

Biomedical subjects

Anders Larsson

Publications and source records attributed to Anders Larsson.

At least 37 records · Page 2Linked to original sources

Mode locking a 1550 nm semiconductor disk laser by using a GaInNAs saturable absorber.

Passive mode locking of an optically pumped, InP-based, 1550 nm semiconductor disk laser by using a GaInNAs saturable absorber mirror is demonstrated. To reduce material heating and enable high-power operation, a 50 microm thick diamond heat spreader is bonded to the surface of the gain chip. The laser operates at a repetition frequency of 2.97 GHz and emits near-transform-limited 3.2 ps pulses with an average output power of 120 mW.

Journal Article↗

Single-frequency operation of a high-power, long-wavelength semiconductor disk laser.

An optically pumped, high-power, single-frequency semiconductor disk laser is demonstrated. A thin (50 microm) diamond bonded to an InGaAsP gain chip provides the combined functions of heat removal and spectral filtering, thus eliminating the need for the additional intracavity etalons that are usually employed for single-frequency operation. In a short cavity (4 mm) configuration we obtained a maximum output power of 470 mW at 0 degrees C and 170 mW at 20 degrees C in a near-diffraction-limited beam (M2 < 1.2). The emission wave-length was 1549 nm and the linewidth was less than 200 MHz.

Journal Article↗

Molecular cloning and characterization of a nuclear androgen receptor activated by 11-ketotestosterone.

Although 11-ketotestosterone is a potent androgen and induces male secondary sex characteristics in many teleosts, androgen receptors with high binding affinity for 11-ketotestosterone or preferential activation by 11-ketotestosterone have not been identified. So, the mechanism by which 11-ketotestosterone exhibits such high potency remains unclear. Recently we cloned the cDNA of an 11-ketotestosterone regulated protein, spiggin, from three-spined stickleback renal tissue. As spiggin is the only identified gene product regulated by 11-ketotestosterone, the stickleback kidney is ideal for determination of the mechanism of 11-ketotestosterone gene regulation. A single androgen receptor gene with two splicing variants, belonging to the androgen receptor-beta subfamily was cloned from stickleback kidney. A high affinity, saturable, single class of androgen specific binding sites, with the characteristics of an androgen receptor, was identified in renal cytosolic and nuclear fractions. Measurement of ligand binding moieties in the cytosolic and nuclear fractions as well as to the recombinant receptor revealed lower affinity for 11-ketotestosterone than for dihydrotestosterone. Treatment with different androgens did not up-regulate androgen receptor mRNA level or increase receptor abundance, suggesting that auto-regulation is not involved in differential ligand activation. However, comparison of the trans-activation potential of the stickleback androgen receptor with the human androgen receptor, in both human HepG2 cells and zebrafish ZFL cells, revealed preferential activation by 11-ketotestosterone of the stickleback receptor, but not of the human receptor. These findings demonstrate the presence of a receptor preferentially activated by 11-ketotestosterone in the three-spined stickleback, so far the only one known in any animal.

Amino Acid Sequence↗

Lung recruitment maneuver depresses central hemodynamics in patients following cardiac surgery.

OBJECTIVE: To assess the impact of the lung recruitment maneuver on circulation following cardiac surgery. DESIGN AND SETTING: Prospective randomized cross-over study at the Departments of Anesthesia and Thoracic Surgery, Copenhagen University Hospital. PATIENTS: Ten adult undergoing coronary artery bypass surgery. INTERVENTIONS: Patients were randomized to two durations of lung recruitment maneuvers (40 cmH2O airway pressure for 10 s and 20 s or vice versa after 5 min) administered immediately after surgery. MEASUREMENTS AND RESULTS: Transesophageal echocardiography (left ventricular short axis view), pulse contour cardiac output, and arterial blood pressure were monitored continuously. Systemic and pulmonary arterial blood gases were sampled before and after each lung recruitment maneuver to calculate the intrapulmonary shunt. Left ventricular end-diastolic areas decreased significantly during both the 10-s and the 20-s lung recruitment maneuvers. Cardiac output was 5.6+/-0.8 l/min at baseline, decreasing by 3.0+/-1.1 l/min and 3.6+/-1.2 l/min during lung recruitment maneuvers of 10 and 20 s, respectively. Shunt decreased from 20+/-5% to 15+/-6% after the first lung recruitment maneuver and from 15+/-6% to 12+/-5% after the second. CONCLUSIONS: Lung recruitment maneuvers markedly reduced cardiac output and left ventricular end-diastolic areas in hemodynamically stable patients following cardiac surgery.

Aged↗

Purification of a 75 kDa protein from the organelle matrix of human neutrophils and identification as N-acetylglucosamine-6-sulphatase.

A 75 kDa protein was purified to homogeneity from granule extracts of normal human granulocytes using Sephadex G-75 chromatography, Mono-S cation exchange chromatography and chromatofocusing. The protein consisted of one chain with a molecular mass of 75 kDa, as determined by SDS/PAGE. Tryptic peptide analysis by MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS and sequence analysis by MS/MS identified the protein to be N-acetylglucosamine-6-sulphatase (EC 3.1.6.14). The identity of the protein was confirmed by demostrating enzymatic activity towards the substrate N-acetylglucosamine 6-sulphate. The enzyme was active over a broad pH range with an optimum of pH 7.0, and showed a K(m) value of 13.0 mM and a V(max) value of approximately 1.8 microM/min per mg. The enzyme also showed O-desulphation activity towards heparan sulphate-derived saccharides. Subcellular fractionation of neutrophil organelles showed the presence of enzymatic activity mainly in the same fractions as primary granules. Furthermore, PMA treatment of the neutrophils induced release of the enzyme, indicating its matrix protein nature. The presence of N-acetylglucosamine-6-sulphatase in human neutrophils implies that neutrophils may play a role in the modulation of cell surface molecules and extracellular matrix by O-desulphation.

Humans↗

Adhesion of the probiotic bacterium Lactobacillus plantarum 299v onto the gut mucosa in critically ill patients: a randomised open trial.

INTRODUCTION: To achieve any possible positive effect on the intestinal mucosa cells it is important that probiotics adhere tightly onto the intestinal mucosa. It has been shown in healthy volunteers that Lactobacillus plantarum 299v (Lp 299v) (DSM 9843), a probiotic bacterium, given orally in a fermented oatmeal formula adheres onto the intestinal mucosa, but whether this also occurs in critically ill patients is unknown. METHODS: After randomisation, nine enterally fed, critically ill patients treated with broad-spectrum antibiotics received an oatmeal formula fermented with Lp 299v throughout their stay in the intensive care unit; eight patients served as controls. Biopsies of the rectal mucosa were made at admission and then twice a week, and the biopsies were analysed blindly. RESULTS: Four patients in the control group were colonised with Lp 299v at admission but thereafter all their biopsies were negative (Lp 299v is an ingredient in a common functional food, ProViva, in Sweden). Of the treated patients none was colonised at admission but three patients had Lp 299v adhered on the mucosa from the second or third biopsy and in the following samples. CONCLUSION: This study shows that Lp 299v could survive the passage from the stomach to the rectum and was able adhere onto the rectal mucosa also in critically ill, antibiotic-treated patients.

APACHE↗

Distributed user interfaces for clinical ubiquitous computing applications.

OBJECTIVES: Ubiquitous computing with multiple interaction devices requires new interface models that support user-specific modifications to applications and facilitate the fast development of active workspaces. METHODS: We have developed NOSTOS, a computer-augmented work environment for clinical personnel to explore new user interface paradigms for ubiquitous computing. NOSTOS uses several devices such as digital pens, an active desk, and walk-up displays that allow the system to track documents and activities in the workplace. RESULTS: We present the distributed user interface (DUI) model that allows standalone applications to distribute their user interface components to several devices dynamically at run-time. This mechanism permit clinicians to develop their own user interfaces and forms to clinical information systems to match their specific needs. We discuss the underlying technical concepts of DUIs and show how service discovery, component distribution, events and layout management are dealt with in the NOSTOS system. CONCLUSION: Our results suggest that DUIs--and similar network-based user interfaces--will be a prerequisite of future mobile user interfaces and essential to develop clinical multi-device environments.

Computer Communication Networks↗

Improved blood compatibility of a stent graft by combining heparin coating and abciximab.

UNLABELLED: The aim of this study was to assess the combined effect of heparin coating of a stent graft and administration of abciximab, on platelet and coagulation activity in vitro. METHODS: Stent grafts with an expanded polytetrafluoroethylene (ePTFE) membrane interfoliated between two stents were deployed in tubings to form Chandler loops. Fresh human blood with a low concentration of heparin and various doses of abciximab was rotated for 1 h, then collected and used for measurements of platelets, thrombin-antithrombin complex (TAT), CD11b, complement and contact activation of coagulation. In the first set of experiments, all stent grafts were heparin coated. There were three study groups: Group 1a (no abciximab, n=5); Group1b (abciximab in a concentration of 3.3 microg/ml, n=5); Group 1c (abciximab in a concentration of 8.3 microg/ml, n=5). In the second set of experiments, the concentration of abciximab was 3.3 microg/ml. There were three study groups: Group 2a (untreated stent grafts, n=4); Group 2b (heparin-coated stent grafts, n=4); Group 2c (heparin-coated PVC tubings with no stent grafts, n=4). RESULTS: In the first set of experiments, there was a significant reduction in platelet count in Group 1c compared to Group 1a and Group 1b. There was a significant reduction in TAT in Group 1b and Group 1c as compared to Group 1a. In the second set of experiments, TAT was reduced in Group 2b and Group 2c compared to Group 2a. Contact activation was lowered in Group 1b and Group 1c as compared to Group 1a for both FXIa-AT (0.088 and 0.088 vs. 0.115) and FXIIa-AT (0.12 and 0.12 vs. 0.19). CONCLUSION: Heparin coating of a stent graft was shown to improve blood compatibility and this was further enhanced by addition of abciximab.

Abciximab↗

Capillary electrophoresis for monitoring the effects of plasmapheresis: a feasibility study.

Plasmapheresis is an established method to treat patients with large monoclonal gammopathies (M-components) that increases the blood viscosity. During plasmapheresis the patient plasma is substituted with a mixture of saline, albumin and normal plasma. The treatment results in a reduction of the M-component in the circulation. Plasmapheresis causes changes in several proteins, which makes monitoring by nephelometric or turbidimetric analysis of specific proteins less suitable. Quantification of paraproteins by nephelometric assays are also known to be associated with technical problems. An alternative could be agarose gel electrophoresis but this method is too slow to permit monitoring during the plasmapheresis. Capillary electrophoresis of plasma proteins can be performed in less than 10 min. We have used the CAPILLARYS capillary electrophoresis system (Sebia, Paris, France) to monitor the effect of plasmapheresis treatment on 22 occasions. The mean reduction in M-component size was 51%, range 33-61%. Capillary electrophoresis is a rapid and inexpensive method that could be used to monitor the effect of plasmapheresis during the actual treatment.

Blood Protein Electrophoresis↗

Effects of dehydroepiandrosterone supplement on health-related quality of life in glucocorticoid treated female patients with systemic lupus erythematosus.

The objective of this study was to evaluate the efficacy of low dose dehydroepiandrosterone (DHEA) on health-related quality of life (HRQOL) in glucocorticoid treated female patients with systemic lupus erythematosus (SLE). Forty one women ( >or= 5 mg prednisolone/day) were included in a double-blind, randomized, placebo-controlled study for 6 months where DHEA was given at 30 mg/20 mg ( or= 46 years) daily, or placebo, followed by 6 months open DHEA treatment to all patients. HRQOL was assessed at baseline, 6 and 12 months, using four validated questionnaires and the patients' partners completed a questionnaire assessing mood and behaviour at 6 months. DHEA treatment increased serum levels of sulphated DHEA from subnormal to normal. The DHEA group improved in SF-36 "role emotional" and HSCL-56 total score (both p<0.05). During open DHEA treatment, the former placebo group improved in SF-36 "mental health" (p<0.05) with a tendency for improvement in HSCL-56 total score (p=0.10). Both groups improved in McCoy's Sex Scale during active treatment (p<0.05). DHEA replacement decreased high-density lipoprotein (HDL) cholesterol and increased insulin-like growth factor I (IGF-I) and haematocrit. There were no effects on bone density or disease activity and no serious adverse events. Side effects were mild. We conclude that low dose DHEA treatment improves HRQOL with regard to mental well-being and sexuality and can be offered to women with SLE where mental distress and/or impaired sexuality constitutes a problem.

Adjuvants, Immunologic↗

Early endotoxin-mediated haemostatic and inflammatory responses in the clopidogrel-treated pig.

We have previously shown that the thrombin inhibiting agent melagatran markedly prolongs aPTT and counteracts creatinine increase in endotoxemic pigs. Against this background the effects of the platelet-inhibiting agent, clopidogrel on basic haemostatic, inflammatory and physiological variables were evaluated during porcine endotoxemia. Clopidogrel (10 mg/kg) or saline was randomly injected i.v. 30 min before start of a 6-h continuous infusion of endotoxin in 12 anaesthetised pigs. Another three pigs were given clopidogrel but not endotoxin. Clopidogrel did not affect physiological variables, formation of activated platelet microparticles, PK, aPTT, platelet count, plasma fibrinogen, TNF-alpha, or IL-6 during porcine endotoxemia. Although renal function, as evaluated by creatinine clearance (CLcr) deteriorated significantly (P = 0.01) in the saline-endotoxin, but not in the clopidogrel-endotoxin group, there was no significant difference between the saline-endotoxin and the clopidogrel-endotoxin groups. Renal biopsies were marked with a FITC-labelled chicken anti-fibrinogen antibody detecting fibrinogen and platelet bound fibrinogen, as a marker of porcine platelet activation, and examined by light microscopy. Evaluation of these immunohistochemical slides did not indicate that clopidogrel, significantly reduced the amount of intrarenal fibrin or fibrinogen depositions. Besides a trend to preserve renal function, clopidogrel did not affect haemodynamics or the coagulatory and inflammatory responses in porcine endotoxemia.

Animals↗

Serum selenium predicts levels of F2-isoprostanes and prostaglandin F2alpha in a 27 year follow-up study of Swedish men.

Low concentrations of selenium (Se) predict mortality and cardiovascular diseases in some populations. The effect of Se on in vivo indicators of oxidative stress and inflammation, two important features of atherosclerosis, in human populations is largely unexplored. This study investigated the longitudinal association between serum selenium (s-Se) and a golden standard indicator of oxidative stress in vivo (8-iso-prostaglandin F2alpha, a major F2-isoprostane), an indicator of cyclooxygenase (COX)-mediated inflammation (prostaglandin F2alpha), high sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6) and serum amyloid A protein (SAA) in a follow-up study of 27 years. The s-Se was measured in 615 Swedish men at 50 years of age in a health investigation. The status of oxidative stress and inflammation was evaluated in a re-investigation 27 years later by quantification of urinary 8-iso-PGF2alpha and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha) and serum hsCRP, SAA and IL-6. Men in the highest quartile of s-Se at age 50 had decreased levels of 8-iso-PGF2alpha compared to all lower quartiles and decreased levels of PGF2alpha compared to all lower quartiles at follow-up. These associations were independent of BMI, diabetes, hyperlipidemia, hypertension, smoking, alpha-tocopherol and beta-carotene at baseline. The s-Se was not associated with hsCRP, SAA or IL-6 at follow-up. In conclusion, high concentrations of s-Se predict reduced levels of oxidative stress and subclinical COX-mediated (but not cytokine-mediated) inflammation in a male population. The associations between Se, oxidative stress and inflammation, respectively, might be related to the proposed cardiovascular protective property of Se.

Aged↗

Chicken anti-protein L for the detection of small amounts of protein L in the presence of IgG.

Protein L is a cell surface protein, expressed by Peptostreptoccocus magnus, which binds to the variable light chains of immunoglobulins without interfering with antigen binding. It can be used for purification of mammalian antibodies of all classes in contrast to the Ig-binding proteins protein A and protein G. Detection of protein L leakage into antibody preparations is important, since protein L could interfere in immunological assays and cause adverse reactions in vivo. Here we have developed a sandwich ELISA for detection of protein L in the presence or absence of mouse IgG utilizing specific chicken IgY antibodies. Protein L does not react with chicken IgY light chains, and it is therefore possible to make an antigen-specific assay. The assay can be used to detect protein L at a concentration of 0.3 ng/mL in the presence of IgG.

Animals↗

Endotoxemia-induced lymphocyte apoptosis is augmented by a hyperinsulinemic-euglycemic clamp.

BACKGROUND: Sepsis and endotoxemia are associated with lymphocyte apoptosis. This has been regarded as harmful, contributing to further immune suppression in already immune-compromised patients. Because normalization of blood glucose improves outcome in critically ill patients, the authors hypothesized that one of the effects of insulin and normoglycemia would be inhibition of lymphocyte apoptosis. Therefore, in this experimental study in pigs, the authors examined the separate and combined effects of acute endotoxemia and a hyperinsulinemic-euglycemic clamp (HEC) on lymphocyte apoptosis. METHODS: After 60 min of stabilization, 38 anesthetized and mechanically ventilated pigs (weight, 35-40 kg) were divided (by randomization performed before the experiment) into four groups and were then studied for 570 min. Group 1 received no intervention. Group 2 received a HEC (5 mm p-glucose, insulin infusion rate of 0.6 mU . kg (-1). min(-1)) for 570 min. Group 3 received a lipopolysaccharide infusion for 180 min. Group 4 was given a combination of a HEC and a lipopolysaccharide infusion. After the 570-min study period, the pigs were killed, and tissue was sampled from the spleen and frozen. In four sections of each sample, the apoptosis of B and T lymphocytes were analyzed using stereologic methods: The number of apoptotic B and T cells was estimated by fluorescence immunohistochemistry with anti-active caspase-3 and either anti-CD21 (B lymphocytes) or anti-CD3epsilon (T lymphocytes). The number of apoptotic B and T lymphocytes was then compared using two-way analysis of variance, and the interaction between endotoxemia and the clamp (hyperinsulinemia and euglycemia) was investigated. RESULTS: Endotoxemia induced apoptosis of B (P < 0.001) and T lymphocytes (P = 0.016) in the spleen, and this effect was independent of the clamp. The ratios of apoptotic cells in the spleen tissue of pigs with and without endotoxemia were 2.4 (confidence interval, 1.7-3.4) and 1.6 (confidence interval, 1.1-2.2) for B and T lymphocytes, respectively. Independent of endotoxin infusion, HEC increased the number of apoptotic lymphocytes (P = 0.029 and P = 0.038 for B and T lymphocytes, respectively). The ratios of the number of apoptotic spleen cells in pigs treated and not treated with HEC were 1.5 (confidence interval, 1.0-2.1) and 1.5 (confidence interval, 1.0-2.1) for B and T lymphocytes, respectively. CONCLUSION: In this porcine model, both endotoxemia and a HEC increased the number of apoptotic B and T lymphocytes in the spleen. Contrary to our hypothesis, lymphocyte apoptosis during acute endotoxemia was augmented by a HEC.

Algorithms↗

Serum amyloid A (SAA) protein and high-sensitivity C-reactive protein (hsCRP) in healthy newborn infants and healthy young through elderly adults.

AIM: To determine the levels of serum amyloid A (SAA) protein and high-sensitivity C-reactive protein (hsCRP) in different age groups. METHODS: Serum samples from 70 healthy newborn infants, 80 blood donors and 81 healthy elderly individuals were analysed using a nephelometric method. The 231 samples were grouped as follows: 35 umbilical cords, 35 newborns, 48 young adults, 28 middle-aged adults, and 85 elderly adults. RESULTS: Serum levels of both SAA and hsCRP were lower in umbilical cords than in the newborns and young, middle-aged and elderly adults (p<0.0001). The SAA and hsCRP levels were comparable in newborns, and young and middle-age adults, but higher in elderly adults (p<0.0001-0.03). SAA (r2=0.159, p<0.0001) and hsCRP (r2=0.059, p<0.0001) were positively correlated with age and to each other (r2=0.385, p<0.0001). CONCLUSION: Serum levels of SAA and hsCRP in umbilical cord blood are close to the detection limit and lower than in the other age groups investigated. The elderly have generally higher levels than the younger age groups, which require higher decision levels in inflammatory diseases, including infections. In newborns and young and middle-aged adults, the lower decision levels of 10 mg/l for SAA and 5 mg/l for CRP are suggested.

Adult↗

Slight increase of serum S-100B during porcine endotoxemic shock may indicate blood-brain barrier damage.

Septic shock is a condition that affects many organs, but little is known about the effects on the central nervous system. S-100B, an acidic low molecular weight protein, has attracted considerable interest as a marker for brain damage and disintegration of the blood-brain barrier. It is released into the cerebrospinal fluid and blood from brain tissue after brain damage. We studied S-100B in a porcine model of endotoxemic shock that resembles human Gram-negative septic shock. Ten piglets received IV endotoxin, and plasma samples were collected before the endotoxin infusion and each hour (1-6 h) during the endotoxin infusion. S-100B was measured by sandwich enzyme-linked immunosorbent assay. Low levels of plasma S-100B were detected, but there was a significant increase in S-100B during Hours 1-5 in comparison with the 0 values. We determined that endotoxemia causes a very small but significant increase in the levels of the widely used brain damage marker serum S-100B. However, it cannot be excluded that the increase in S-100B could be caused by release from organs other than the brain.

Animals↗

The role of cystatin C and the angiogenic cytokines VEGF and bFGF in patients with esophageal carcinoma.

Angiogenesis is the formation of new blood vessels out of the existing vascular bed. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) are potent circulating angiogenic factors, whereas cystatin C is one of the most important extracellular inhibitors of several cysteine proteinases. Because proteases degrade interstitial connective tissue and basement membranes during tumor growth and metastasis, an association between cystatin C and the angiogenic factors seems plausible. The primary aim of the present study was to investigate if such a correlation exists between these serum markers. The secondary aim was to determine the prognostic value of these circulating cytokines and cystatin C, collected prior to therapy, in patients with esophageal carcinoma.A total of 42 patients with esophageal carcinoma donated serum samples prior to therapy. VEGF and bFGF were correlated to platelet and leukocyte counts and VEGF was correlated to tumor volume (p = 0.04), whereas bFGF was not (p = 0.08). VEGF was significantly correlated with cystatin C (p = 0.027). Survival analysis showed that VEGF regarded as a continuous variable was associated with a significantly poorer survival in the univariate analysis (p = 0.023); however, this was not found for bFGF (p = 0.46). Neither of the angiogenic factors were associated with survival in the multivariate analysis. In the univariate analysis, cystatin c was correlated with survival (p = 0.01), but this was not found in the multivariate analysis (p = 0.28). In conclusion, VEGF was correlated with cystatin C, possible explanations being discussed in the present article. Results of the present study indicate that use of the angiogenic factors as prognostic factors, prior to therapy in patients with esophageal carcinoma, appears limited.

Cystatin C↗

Type 1 diabetes is associated with increased cyclooxygenase- and cytokine-mediated inflammation.

OBJECTIVE: The extent of involvement of cyclooxygenase (COX)-mediated inflammation in type 1 diabetes is unknown, and the association between the COX- and cytokine-mediated inflammatory responses in type 1 diabetes is not fully understood. RESEARCH DESIGN AND METHODS: Plasma high-sensitivity C-reactive protein (CRP), 24-h urinary and plasma 15-keto-dihydro-prostaglandin F(2alpha) (a metabolite of prostaglandin F(2alpha) [PGF(2alpha)] and an indicator of COX-mediated inflammation), serum amyloid protein A (SAA), and interleukin (IL)-6 (indicators of inflammation) were measured in 38 subjects with type 1 diabetes and 41 healthy age- and sex-matched control subjects. RESULTS: The inflammatory indicators (urinary 15-keto-dihydro-PGF(2alpha), P < 0.01; IL-6, P < 0.04) were increased in men with diabetes. CRP and SAA did not show any significant difference between the diabetic and the control subjects. Urinary levels of 15-keto-dihydro-PGF(2alpha) correlated with the degree of glycemic control, HbA(1c) (r = 0.42, P < 0.0005). No correlation was found between the duration of diabetes and the inflammatory biomarkers or metabolic measurements. CONCLUSIONS: These results suggest that an early low-grade inflammatory process reflected by elevated levels of PGF(2alpha) and IL-6 is involved in type 1 diabetes. Thus, both COX- and cytokine-mediated inflammatory pathways are significantly related to type 1 diabetes.

Adult↗