Search PubMed⌕ Search

Biomedical subjects

G Eriksson

Publications and source records attributed to G Eriksson.

At least 19 recordsLinked to original sources

Genetic variation in carbon isotope discrimination in six European populations of Castanea sativa Mill. originating from contrasting localities.

The objective of this study was to evaluate the variability of physiological performances of Castanea sativa Mill. in relation to drought tolerance, among and within European populations coming from contrasting environmental conditions. Forty-eight open-pollinated families from a stratified sample (temperature/precipitation) of six naturalized populations from Spain, Italy and Greece were grown for one growth period under two temperature regimes (25 and 32 degrees C), in combination with two watering regimes in growth chambers. Complementary to growth traits analysed in a previous study, carbon isotope discrimination (Delta), a complex physiological trait involved in acclimation and adaptive processes, was studied. anova indicated significant Delta variability for C. sativa populations across Europe and, thereby, variation in adaptedness to drought. The European pattern of Delta variability matches the previously reported one for the centre of origin of C. sativa (Ponto-Caucasian region). This suggests that common mechanisms of drought adaptedness, involving both genetic and physiological determinants, give C. sativa the capacity to colonize a wide range of site conditions. The highest Delta values, indicating the lowest water-use efficiency (WUE), were found within each treatment for populations originating from Mediterranean drought-prone sites. These populations also had the highest phenotypic plasticity of Delta. Significant among-family genetic variation in Delta was found. The heritability based on the joint anova was estimated at 0.31 +/- 0.07. The estimates of the coefficients for the additive variance varied in the range 2.6-4.0%, suggesting possibilities for selection on WUE and adaptedness to drought. The genetic correlations between Delta and growth traits were generally strong and negative, especially in the two high temperature treatments.

Adaptation, Physiological↗

Thermodynamic modeling of PCDD/Fs formation in thermal processes.

Three thermodynamic databases of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), derived using the Group Additivity approach and two computational molecular modeling methods, Modified Neglect of Diatomic Overlap (MNDO) and Parametrized Model 3 (PM3), respectively, combined with the Scientific Group Thermodata Europe (SGTE) database have been used to model the formation of PCDD/Fs in thermal processes, such as iron ore sintering process. The predictions using the three different databases are compared, and similar thermodynamic conditions of PCDD/Fs formation are found. The comparison of the calculated values with measured results obtained from industrial iron ore sinter plant indicates that the PCDDs and PCDFs found in practice are not in equilibrium with each other. While within each dioxin and furan homologue equilibrium between the isomers appears to be established in industrial processes, reactions between dioxins and furans seem to be kinetically inhibited. This view has been supported by assuming no reaction at all between PCDFs and PCDDs in the simulation. With this assumption, both PCDFs and PCDDs reached partial pressures between 600 and 800 K in the order of magnitude actually found in practice. Taking this restriction into account, the conditions for PCDD/Fs formation were calculated as a function of oxygen partial pressure; temperature; concentrations of carbon, hydrogen, and chlorine; and C/H ratio.

Benzofurans↗

Alcohol biomarkers: clinical significance and biochemical basis.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Raj Lakshman and Mikihiro Tsutsumi. The presentations were (1) Sialic acid index of apolipoprotein J: A new marker for chronic alcohol consumption, by P. Ghosh and M. R. Lakshman; (2) Microheterogeneity of serum glycoproteins in alcoholics, by M. Tsutsumi and S. Takase; (3) Probing protein-ethanol adducts with combinatorial peptide libraries displayed by filamentous phage, by H. Anni, O. Nikolaeva, and Y. Israel Y; (4) Carbohydrate-deficient transferrin as a marker for heavy alcohol use: What have we learned; Where do we go from here, by R. F. Anton; (5) Sensitivity and specificity of carbohydrate-deficient transferrin in drinking experiments and different patient groups, by O. M. Lesch; (6), Transferrin variants interfere with the measurement of carbohydrate-deficient transferrin, by A. Helender, G. Eriksson, and J-O. Jeppson; and (7) Chronic ethanol on protein trafficking in liver, by P. Marmillot, M. N. Rao, and M. R. Lakshman.

Alcoholism↗

Increased gene expression of interleukin-1alpha and interleukin-6 in rat primary glial cells induced by beta-amyloid fragment.

One of the pathological hallmarks of Alzheimer's disease (AD) is the presence of amyloid plaques. The main constituent of the amyloid plaques is the amyloid beta-peptide (A beta) shown to activate glial cells in vitro. A growing body of evidence suggests that these cells contribute to neurotoxicity through production of inflammatory cytokines, chemokines, and neurotoxic substances, such as reactive oxygen species (ROS). In this study, mRNA levels of the inflammatory cytokines interleukin (IL)-1alpha and beta, and IL-6 were analysed by reverse transcriptase-polymerase chain reaction (RT-PCR) in rat primary mixed glial cells after treatment with A beta(25-35), a biologically active fragment of A beta peptide with neurotoxic properties. Clear morphological changes of the astrocytes, as well as proliferation and clustering of microglial cells were observed by light and immunofluorescence microscopy after 24 h treatment. Significant increases in IL-1alpha and IL-6 mRNA levels were detected after 24 and 72 h, whereas significantly increased levels of IL-1beta mRNA could only be detected after 4 h treatment. The most pronounced effect was seen on IL-6 mRNA expression, which increased approx two- to threefold after treatment. In addition, increased secretion of IL-6 was detected after 96 h exposure. Recently, association of IL-1alpha and IL-6 gene polymorphism with AD was reported, suggesting that these cytokines may play an important role in the development of the disease. The increased mRNA levels of IL-1alpha and IL-6 in parallel with the morphological changes in the mixed glial-cell cultures support that these cytokines may be involved in A beta-induced gliosis and in the pathogenesis of AD.

Amyloid beta-Peptides↗

Interference of transferrin isoform types with carbohydrate-deficient transferrin quantification in the identification of alcohol abuse.

BACKGROUND: Isoforms of transferrin interfere with measurement of carbohydrate-deficient transferrin (CDT) as a marker of heavy alcohol consumption. We evaluated the rate of inaccurate CDT results by immunoassays. METHODS: We studied 2360 consecutive sera (1614 individuals) submitted for CDT assay without clinical information as well as samples from 1 patient with a congenital disorder of glycosylation (CDG Ia) and from 6 healthy carriers of CDG Ia. The CDTect, %CDT-TIA, and new %CDT immunoassays were compared with HPLC (%CDT-HPLC). Transferrin isoform pattern were evaluated by isoelectric focusing (IEF). RESULTS: Transferrin BC and CD heterozygotes were found at frequencies of approximately 0.7% and approximately 0.2%, respectively. Another transferrin C subtype, where di- and trisialotransferrin partly coeluted (tentatively identified as C2C3), was observed in approximately 0.6%. Compared with the %CDT-HPLC method, the immunoassays often produced low results for transferrin BC and high results for transferrin CD and "C2C3". A very high trisialotransferrin value (frequency approximately 1%) often produced high CDT immunoassay results. In four of six healthy carriers of CDG Ia, a- and disialotransferrin were highly increased and the HPLC and IEF isoform patterns were indistinguishable from those in alcohol abuse. CONCLUSIONS: Rare transferrin isoform types and abnormal amounts of trisialotransferrin (total frequency approximately 2-3%) may cause incorrect determination of CDT with immunoassays. The observed variants were readily identified by HPLC and IEF, which can be recommended for verification of CDT immunoassay results in doubtful cases. In healthy carriers of CDG Ia, CDT is high by all assays.

Alcoholism↗

[Risky alcohol drinking surveyed at a GP unit. Secondary prevention of alcohol problems in primary care patients].

This article describes an implementation of secondary prevention of alcohol abuse at a GP unit in southern Gothenburg, Sweden. During several periods between 1994 and 1996, screening for alcohol problems was performed using either AUDIT or a 4-item instrument called SWAG. In one part of the study, screening was simultaneously carried out using gamma-GT and MCV. The main object of screening efforts was to stimulate interest for alcohol-related conditions, and this goal was reached. The staff was trained in treatment techniques such as motivational interviewing (MI), bio-feedback using gamma-GT and delivery of concise information. Simple methods to determine level of motivation were used for treatment stratification. Some doctors reported that they had insufficient time for adequate MI treatment, and therefore a condensed model was sometimes used. A nurse-staffed treatment unit was started and successfully promoted work with alcohol problem. Attempts were made to spread these methods to other GP units in the region and this was partially successful, although support from the central primary care administration was not secured.

Adolescent↗

On demand therapy with omeprazole for the long-term management of patients with heartburn without oesophagitis--a placebo-controlled randomized trial.

AIM: To observe the natural course of gastro-oesophageal reflux disease (GERD) in patients without oesophagitis following effective symptom relief, and to determine the place of acid pump inhibitor therapy in the long-term management of these patients. METHODS: We investigated the efficacy of on-demand therapy with omeprazole 20 mg or 10 mg, or placebo in a double-blind, randomized multicentre trial. It involved 424 patients with troublesome heartburn without endoscopic evidence of oesophagitis in whom heartburn had been resolved with short-term treatment. Patients were told to take study medication on demand once daily on recurrence of symptoms until symptoms resolved over a 6-month period. They also had access to antacids. The primary efficacy variable was time to discontinuation of treatment, due to unwillingness to continue. RESULTS: According to life-table analysis, after 6 months the remission rates were 83% (95% CI: 77-89%) with omeprazole 20 mg, 69% (61-77%) with omeprazole 10 mg, and 56% (46-64%) with placebo (P < 0.01 for all intergroup differences). The mean (s.d.) number of study medications used per day in these groups was 0.43 (0.27), 0.41 (0.27) and 0.47 (0.27), respectively. The use of antacids was highest in the placebo group and lowest in the omeprazole 20 mg group. Treatment failure was associated with more than a doubling of antacid use, and a deterioration in patient quality of life. CONCLUSIONS: Approximately 50% of patients with heartburn who do not have oesophagitis need acid inhibitory therapy in addition to antacid medication to maintain a normal quality of life. On-demand therapy with omeprazole 20 mg, is an effective treatment strategy in these patients.

Adult↗

Hypersensitive cytokine response to beta-amyloid 25-35 in astroglial cells from IL-1 receptor type I-deficient mice.

betaA25-35, a neurotoxic fragment of the Alzheimer beta-amyloid peptide (betaA), acts as a strong inducer of pro-inflammatory cytokines, such as interleukin (IL)-1 and IL-6, in glial cells. Since IL-1 is known to induce expression of both IL-1 and IL-6, we have investigated to what extent the induction of IL-1alpha and IL-6 by betaA25-35, is dependent on the IL-1 receptor type I (IL-1RI), the only known signalling IL-1 receptor. Primary astroglial cell cultures prepared from wild-type and IL-1RI-deficient mice were incubated in the presence of betaA25-35 (100 microM) for 19 h, followed by analysis of mRNA levels of IL-1alpha and IL-6. Cell cultures treated with betaA25-35 showed a significant increase in mRNA levels for IL-1alpha and IL-6 and in addition increased levels of IL-1alpha immunoreactivity. A supersensitive IL-1alpha response was observed in astroglial cell cultures lacking the IL-1 RI as compared to betaA25-35 treated cell cultures from wild-type mice. In contrast the betaA25-35-induced increase of IL-6 was lower in the absence of IL-1RI. In conclusion, these results suggest that a functional IL-1 signal transduction is not necessary for induction of mRNA levels of IL-1alpha and IL-6 in astroglial cell cultures treated with betaA25-35, but that induction of IL-6 involves at least two distinct mechanisms, one of which occurs via activation of the IL-1RI.

Amyloid beta-Peptides↗

Interleukin-1-mediated febrile responses in mice and interleukin-1 beta activation of NFkappaB in mouse primary astrocytes, involves the interleukin-1 receptor accessory protein.

The endogenous pyrogen interleukin-1 (IL-1) is considered as one of the key molecules in orchestrating the host response of injury and inflammation. IL-1 exerts its effects upon binding to the type I IL-1 receptor (IL-1RI). The IL-1-IL-1RI complex is further thought to associate with the IL-1 receptor accessory protein (IL-1RAcP), which is suggested to be important for most IL-1 signal transduction pathways. With the aim of investigating the importance of the IL-1RAcP in IL-1 signalling, IL-1alpha and IL-1beta induced febrile responses and IL-1beta-mediated activation of NFkappaB in primary astrocyte cultures were examined using IL-1RAcP-deficient (IL-1RAcP KO) and wild type mice, respectively. It was shown that neither recombinant rat IL-1alpha (rrIL-1alpha, 25 microg/kg), recombinant rat IL-1beta (rrIL-1beta, 40 microg/kg) nor recombinant human IL-1beta (rhIL-1beta, 50 microg/kg) injected i.p. could elicit febrile responses in the IL-1RAcP-deficient mice, while the same doses of rrIL-1alpha/beta or rhIL-1beta injected into wild type mice caused normal fever responses. A febrile response could be induced in the IL-1RAcP-deficient mice by i.p. administration of E. coli lipopolysaccharide (LPS, 50 microg/kg) and this response was similar to that obtained in wild type mice. Furthermore, it was shown that rhIL-1beta activated, in a concentration-dependent manner, nuclear translocation of the transcriptional nuclear factor kappa B (NFkappaB) in primary astrocyte cultures prepared from wild type mice, whereas no IL-1beta-induced translocation of NFkappaB could be detected in cultures prepared from IL-1RAcP-deficient mice, as revealed by electrophoretic mobility shift assay (EMSA). The rhIL-1beta-induced NFkappaB complexes were shown to contain p50 but no, or very little, p65 and cRel immunoreactive proteins.

Animals↗

Long-term follow-up of patients with obstructive sleep apnea treated with uvulopalatopharyngoplasty.

OBJECTIVE: To study the long-term outcome after treatment with uvulopalatopharyngoplasty (UPPP). DESIGN: Long-term follow-up (4-8 years) with polysomnography. SETTING: Referral center for patients with sleep-disordered breathing. PATIENTS: Thirty-four consecutive patients of whom 25 (22 men and 3 women; mean age, 49 years) participated in the follow-up. All patients had obstructive sleep apnea syndrome. INTERVENTION: Uvulopalatopharyngoplasty. MAIN OUTCOME MEASURES: Symptoms and apnea-hypopnea index (AHI) before and after UPPP. Response to treatment defined as a 50% or more reduction in AHI and a postoperative AHI of 10 or less. RESULTS: Reduced prevalence of snoring and daytime sleepiness and reduction in AHI (mean [+/-SD], 40 +/- 26 to 21 +/- 21) at follow-up (P < .001). Sixteen patients (64%) were responders after 6 months and 12 (48%) at the long-term follow-up. Responders had a lower preoperative AHI (25 +/- 7) than did nonresponders (48 +/- 29) (P < .05). None of the 7 patients with preoperative AHI of more than 40 were responders (P < .01). No difference was seen in preoperative body mass index, lung function, ventilatory response to carbon dioxide, computed tomography scan of upper airways, or change in body mass index between responders and nonresponders. CONCLUSIONS: Four to 8 years after UPPP, about half of our patients were clinically and objectively improved. Uvulopalatopharyngoplasty should be reserved for patients with mild or moderate obstructive sleep apnea. After UPPP, long-term follow-up is recommended because some initially successfully treated patients will relapse in the long term.

Female↗

Storage of buffy coat preparations at 22 degrees C in plastic containers with different gas permeability.

BACKGROUND: Buffy coats (BCs) are used as an alternative to platelet-rich plasma in the preparation of platelet concentrates (PCs). For this purpose the BCs have to be stored for same time at 20-24 degrees C which implies cellular metabolic activity. However, little information is available concerning the effects of a number of factors which may influence the suitability of the preparation as the source of PC. STUDY DESIGN AND METHODS: We studied the effects on BCs of a high and low gas permeability of the wall of the plastic containers, PL2209 and PL146, respectively, mixing versus non-mixing during storage for 48 h at 22 degrees C, and two types of anticoagulant solutions, CPD and half strength citrate CPD (0.5CPD). The buffy coats were prepared by the bottom and top technique. The median values of volume and haematrocrit were 58-64 ml and 39-45%, respectively. A total of 48 BCs were tested. Blood gases, pH, bicarbonate concentration and haemolysis were determined in the blood mixtures and beta-thromboglobulin (beta-TG), lactate dehydrogenase (LDH), complement factor 3a, and elastase in the extracellular fluid. RESULTS: The pH decreased in all units but to a lesser extent in PL2209 containers than in PL146 units. In the former the pCO2 decreased slowly in contrast to the latter where it increased by about 50%. Mixing during storage increased the pH and decreased the pCO2 in 0.5CPD-PL146 and CPD-PL2209 units, as compared to resting, while no effects of mixing were observed in the other groups. The pO2 decreased to low levels in PL146 units. The haemolysis and LDH release were higher in mixed than in unmixed units. The initial beta-TG levels were lowest in 0.5CPD-PL146 units which also had the lowest 24-hour levels. The release of beta-TG during storage was smallest in CPD resting units. The elastase release was significantly higher in 0.5CPD than in CPD units already from the beginning of storage and increased during storage at about the same rate irrespective of mixing. The C3a levels were higher in 0.5CPD-PL2209 units than in the other units at 2 h. Storage for 24 h caused an increase by 2-3 times of the original level without any clear relation to storage conditions. CONCLUSIONS: In BC units accumulation of CO2 occurs in containers with low gas permeability. These also show the most rapid pH decrease during storage. Prolonged holding of BCs puts extra emphasis on the need of satisfactory gas permeability of the container for platelet storage in BC-derived PCs. Continuous mixing causes red cell damage and does not seem to have any clear benefit. The release of granulocyte elastase was higher in 0.5CPD than in CPD units but there was no indication of an associated increase in platelet activation. SUMMARY: Study of buffy coats stored in various media and containers at 22 degrees C suggests that it is better to restrict storage to 24 h or less to avoid activation or other deleterious effects on the platelets.

Blood Gas Analysis↗

Sodium-dependent glutamate uptake as an activator of oxidative metabolism in primary astrocyte cultures from newborn rat.

In the present report we describe the effect of glutamate on respiratory activity in primary cultures of astrocytes, derived from cerebral cortex of newborn rat. Glutamate (100 microM) caused an increased oxygen consumption. This effect could not be inhibited by antagonists to the NMDA or AMPA/kainate receptors. Neither trans-ACPD (an agonist to the metabotropic glutamate receptor) nor the Krebs cycle intermediate alpha-ketoglutarate had any effect on the respiratory rate. An uncontrolled influx of Na+, caused by gramicidin, could mimic the glutamate effect on respiratory activity. In addition, the glutamate effect was abolished by addition of ouabain or replacement of Na+ by Li+ in the perfusion buffer. We conclude that the co-transport of Na+, in the Na(+)-dependent high-affinity glutamate uptake system, mediated the glutamate-induced increase in oxygen consumption through an increased activity of Na+/K(+)-ATPases.

Animals↗

Use of primary cultures and continuous cell lines to study effects on astrocytic regulatory functions.

1. Current opinions on the mechanisms for glutamate-mediated neurotoxicity are reviewed. The protective role of astrocytic high-affinity glutamate transport is also discussed. 2. Low-density seeding of primary astrocytes from rat hemispheres was found to result in the development of reactive-like astrocytes. Typical glial signs of amyotrophic lateral sclerosis (ALS) could not be induced in astrocyte cultures by serum from ALS-patients. 3. Glutamate (100 mumol/L) was found to induce an increase in respiratory activity in primary cultures of astrocytes. This stimulation appeared to be related to the co-transport of Na2+ with glutamate and a resulting activation of Na2+/K(+)-ATPase. Both basal respiration and glutamate-stimulated oxygen consumption was inhibited by organic solvents. 4. Preliminary results show that heavy metals cause an increase in the mitochondrial DNA content at concentrations that have no effect on growth rate or morphology in a glial cell line. This increase was accompanied by an inhibition of oxygen consumption and an increased production of lactate at unaltered ATP levels.

Amyotrophic Lateral Sclerosis↗

Dielectric spectroscopy of human blood.

Impedance measurement is an established technique for studying the passive electric properties of cell membranes. Dispersions can be detected by studying the electric properties (capacitance and conductance) in the radio-frequency range (kHz-mHz). The theoretical interpretation is based on the Maxwell-Wagner effect at the interface between the cytoplasm and the cell membrane. The specific electric variables of the membrane, the cytoplasm, as well as the surrounding plasma (medium) are estimated by non-linear regression fitting and appropriate equations. Using a four-electrode technique, we have measured the impedance with a commercial instrument working in the frequency range of 0.2-10 mHz interfaced to a computer. Differences were found in conductivity and capacitance of blood from 1) persons exposed to organic solvents, 2) patients with metal exposure, and 3) patients with cardiovascular disease. The effects of plasma components and haematocrit are crucial when undertaking measurements on whole blood. The results are difficult to interpret but we consider perturbations in the erythrocyte membrane to be involved. Potential clinical applications will be promoted by the development of the software.

Aspirin↗