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J Larsson

Publications and source records attributed to J Larsson.

At least 37 records · Page 2Linked to original sources
PubMed2001

Distribution of iodine 125-labeled alpha1-microglobulin in rats after intravenous injection.

The 28-kd plasma protein alpha(1)-microglobulin is found in the blood of mammals and fish in a free, monomeric form and as high-molecular-weight complexes with molecular masses above 200 kd. In this study, iodine 125-labeled free and high-molecular weight rat alpha(1)-microglobulin (a mixture of alpha(1)-microglobulin/alpha(1)-inhibitor-3 and alpha(1)-microglobulin/fibronectin complexes) were injected intravenously into rats. The distribution of the proteins was measured by using scintillation camera imaging. Both forms of (125)I-labeled alpha(1)-microglobulin were rapidly cleared from the blood, with a half-life of 2 and 16 minutes for the initial and late phase, respectively, for free alpha(1)-microglobulin; and a half-life of 3 and 130 minutes for the initial and late phase, respectively, for the complexes. After 45 minutes, 6%, 16%, 27%, 13%, and 34% of the free (125)I-labeled alpha(1)-microglobulin and 18%, 21%, 6%, 10%, and 42% of the (125)I-labeled alpha(1)-microglobulin complexes were found in the blood, gastrointestinal tract, kidneys, liver, and the remainder of the body, respectively. The local distribution of injected (125)I-labeled alpha(1)-microglobulin in intestines and kidneys was investigated by microscopy and autoradiography. In the intestine, both forms were distributed in the basal layers, villi, and luminal contents. The results also suggested intracellular labeling of epithelial cells. Well-defined local regions containing higher concentrations of injected protein could be seen in the intestine. In the kidneys, both forms were found mostly in the cortex. Free (125)I-labeled alpha(1)-microglobulin was found predominantly in epithelial cells of a subset of the tubules, whereas the (125)I-labeled complexes were more evenly distributed. Intracellular labeling was indicated for both alpha(1)-microglobulin forms. The results thus indicate a rapid transport of (125)I-labeled alpha(1)-microglobulin from the blood to most tissues.

Animals↗
PubMed2001

Receptors and ligands for autocrine growth pathways are up-regulated when pancreatic cancer cells are adapted to serum-free culture.

Overexpression of autocrine growth factors and their receptors has been reported in many human cancers. The study of autocrine-regulated pathways using in vitro culture systems can be hindered by the presence of fetal bovine serum in culture medium. A human pancreatic cancer cell line (HPAF) was slowly weaned from its dependence on fetal bovine serum and subsequently maintained in serum-free conditions. Growth factor secretion studies showed that production of autocrine growth factors such as transforming growth factor alpha, gastrin-releasing peptide, and insulin-like growth factor I from weaned cells increased three times compared with nonweaned cells (p < 0.01). The epidermal growth factor and gastrin-releasing peptide receptor densities were also increased in weaned cells (2 times and 2.5 times, respectively, p < 0.05). The proliferation of weaned cells cultured continuously in the same medium was significantly greater than of nonweaned cells (p < 0.05). Collectively, these data indicate that weaned pancreatic cancer cells can proliferate in the absence of serum by up-regulating autocrine pathways.

Binding, Competitive↗
PubMed2001

Photopic 30 Hz flicker ERG as a predictor for rubeosis in central retinal vein occlusion.

AIMS: To investigate the predictive value of the cone b-wave implicit time in the photopic compared with the scotopic 30 Hz flicker ERG for rubeosis in central retinal vein occlusion. METHODS: 44 patients with a central retinal vein occlusion were examined with full field electroretinogram (ERG). RESULTS: The average implicit time in the photopic 30 Hz flicker ERG in patients who developed rubeosis (n=15) was 38.3 ms. In the patients who did not develop rubeosis (n=29) it was 31.3. The difference is statistically significant (p=0.0000000004). CONCLUSION: The photopic cone b-wave implicit time in the 30 Hz flicker ERG is a good predictor for rubeosis.

Adult↗
PubMed2001

Su(z)12, a novel Drosophila Polycomb group gene that is conserved in vertebrates and plants.

In both Drosophila and vertebrates, spatially restricted expression of HOX genes is controlled by the Polycomb group (PcG) repressors. Here we characterize a novel Drosophila PcG gene, Suppressor of zeste 12 (Su(z)12). Su(z)12 mutants exhibit very strong homeotic transformations and Su(z)12 function is required throughout development to maintain the repressed state of HOX genes. Unlike most other PcG mutations, Su(z)12 mutations are strong suppressors of position-effect variegation (PEV), suggesting that Su(z)12 also functions in heterochromatin-mediated repression. Furthermore, Su(z)12 function is required for germ cell development. The Su(z)12 protein is highly conserved in vertebrates and is related to the Arabidopsis proteins EMF2, FIS2 and VRN2. Notably, EMF2 is a repressor of floral homeotic genes. These results suggest that at least some of the regulatory machinery that controls homeotic gene expression is conserved between animals and plants.

Amino Acid Sequence↗
PubMed2001

A 4D approach to the analysis of functional brain images: application to FMRI data.

This paper presents a new approach to functional magnetic resonance imaging (FMRI) data analysis. The main difference lies in the view of what comprises an observation. Here we treat the data from one scanning session (comprising t volumes, say) as one observation. This is contrary to the conventional way of looking at the data where each session is treated as t different observations. Thus instead of viewing the v voxels comprising the 3D volume of the brain as the variables, we suggest the usage of the vt hypervoxels comprising the 4D volume of the brain-over-session as the variables. A linear model is fitted to the 4D volumes originating from different sessions. Parameter estimation and hypothesis testing in this model can be performed with standard techniques. The hypothesis testing generates 4D statistical images (SIs) to which any relevant test statistic can be applied. In this paper we describe two test statistics, one voxel based and one cluster based, that can be used to test a range of hypotheses. There are several benefits in treating the data from each session as one observation, two of which are: (i) the temporal characteristics of the signal can be investigated without an explicit model for the blood oxygenation level dependent (BOLD) contrast response function, and (ii) the observations (sessions) can be assumed to be independent and hence inference on the 4D SI can be made by nonparametric or Monte Carlo methods. The suggested 4D approach is applied to FMRI data and is shown to accurately detect the expected signal.

Brain Chemistry↗
PubMed2001

Obesity increases the severity of acute experimental pancreatitis in the rat.

BACKGROUND: Studies in patients with acute pancreatitis have shown a correlation between obesity and serious complications or a fatal outcome. However, the mechanisms by which obesity aggravates acute pancreatitis are not known. In the present study we used the sodium taurocholate model of pancreatitis to examine the effect of obesity on severity and outcome in acute experimental pancreatitis (AEP). METHODS: AEP was induced at two degrees of severity by retrograde infusion of sodium taurocholate (0.2 ml x 3% or 0.4 ml x 3.5%) into the pancreatic duct of rats with obesity induced by high-fat diet, genetically obese (GO) rats or lean control rats. Surviving animals were sacrificed 72 h after induction of pancreatitis. RESULTS: In the low-dose experiment, there were no significant differences in pancreatic histology or survival rate between the groups. In the high-dose experiment, the GO rats had a significantly lower 72-h survival rate than the high-fat obese (HFO) or lean control (LC) groups (GO 25% versus HFO 73%, P < 0.05; GO 25% versus LC 100%, P < 0.001). Survival rates in the high-dose experiment correlated strongly with basal liver fat content (R2 = 0.86). Pancreatic histology showed significantly more fat necrosis and a higher total pathological mean score in the HFO rats than in the LC animals (both P < 0.05). CONCLUSIONS: Obesity had a negative influence on the outcome of necrotizing pancreatitis that was related to the magnitude of the pancreatic insult. The sodium taurocholate model in obese rats would be useful for future mechanistic studies of the effect of obesity on pancreatitis.

Animals↗
PubMed2000

Effects of long-term infusion of anorexic concentrations of islet amyloid polypeptide on neurotransmitters and neuropeptides in rat brain.

Islet amyloid polypeptide (IAPP or amylin) potently reduces food intake in rats at or near physiological concentrations. Although the mechanisms of action of IAPP are not understood, the brain is a suggested site. Changes in hypothalamic and striatal neurotransmission have been reported following acute systemic administration of a pharmacological concentration of IAPP. In the current study, we evaluated the effects of chronic administration of low doses of IAPP on satiety-related neurotransmitters and neuropeptides in the hypothalamus, hippocampus, striatum, left cortex, and right cortex of the rat. Doses of 0, 5 and 25 pmol IAPP/kg-min were administered subcutaneously for 2 or 5 days. Food intake was reduced by 27 and 44% (both P<0.001) for the 5 and 25 pmol/kg-min groups, respectively, in the 2-day experiment and was decreased by 14% (P<0.01) and 24% (P<0.001), respectively, in the 5-day experiment. Body weight was significantly decreased in a dose-dependent fashion. In the 2-day experiment, norepinephrine increased in the hypothalamus in the 5 pmol IAPP/kg-min group, and neurotensin increased in the hippocampus in the 25 pmol/kg-min rats (both P<0.05). In the 5-day, 5 pmol/kg-min rats, 5-hydroxyindoleacetic acid (5-HIAA) increased in the hypothalmus and cholecystokinin (CCK) increased in the striatum (both P<0.05). In the 5-day, 25 pmol/kg-min group, neuropeptide Y (NPY) increased in the hypothalamus (P<0.01) and CCK increased in the hypothalmus and striatum (both P<0.05). The present study confirms that IAPP is a potent anorectic peptide at low doses and suggests that IAPP not only affects classical neurotransmitters in the brain but also alters concentrations of neuropeptides known to be involved in food intake.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

[Guidelines for management of patients with acute pancreatitis].

During recent years new concepts and methods have been introduced in the management of acute pancreatitis. Severity and risk of complications show wide variation. Outcome is also dependent on the physician's experience and on his local resources. In this light the Swedish Society of Upper Abdominal Surgery has elaborated national guidelines for management. Attention is paid to diagnosis, severity assessment and etiology. Furthermore, guidelines are offered for treatment of mild and severe pancreatitis, as well as for the management of pseudocysts. The role of multidisciplinary intensive care specialist teams in the management of severe disease is emphasized. The guidelines are supported by the Swedish Society of Gastroenterology, the Swedish Society of Gastroenterology, the Swedish Society of Anesthesiology and Intensive Care and by experts from other Nordic countries.

APACHE↗
PubMed2000

Time-resolved X-Ray diffraction from coherent phonons during a laser-induced phase transition

Time-resolved x-ray diffraction with picosecond temporal resolution is used to observe scattering from impulsively generated coherent acoustic phonons in laser-excited InSb crystals. The observed frequencies and damping rates are in agreement with a model based on dynamical diffraction theory coupled to analytic solutions for the laser-induced strain profile. The results are consistent with a 12 ps thermal electron-acoustic phonon coupling time together with an instantaneous component from the deformation-potential interaction. Above a critical laser fluence, we show that the first step in the transition to a disordered state is the excitation of large amplitude, coherent atomic motion.

Journal Article↗
PubMed2000

Involvement of the beta2-integrin CD18 in apoptosis signal transduction in human neutrophils.

OBJECTIVE AND DESIGN: To examine the hypothesis that an accelerated rate of neutrophil apoptosis occurs following beta2-integrin activation, and further investigate the signal transduction pathways involved. MATERIAL: Human polymorphonuclear neutrophils. TREATMENT: Neutrophils were challenged with pansorbins coated with antibodies towards the beta2-integrin subunit CD18 in a proportion of 1:100 with or without the inhibitors diphenylene iodonium (10 M), cytochalasin B (5 microg/ml), genistein (10 nM), herbimycin A (10 M) and Z-VAD-FMK (10 microM). METHODS: Measurement of phosphatidylserine exposure and DNA fragmentation in flow cytometry and assessment of H2O2-production through spectrofluorometry. The results were analysed using Mann Whitney U test and Kruskal Wallis. RESULTS: Pansorbins coated with antibodies to CD18 induce apoptosis in neutrophils (p<0.01), and activate the production of reactive oxygen species (p<0.01). Pre-treatment with the inhibitors have no effect on anti-CD 18 induced apoptosis. CONCLUSION: Anti-CD18 pansorbins induce apoptosis in neutrophils through an alternative pathway not involving reactive oxygen species and independent of tyrosine phosphorylation, cytoskeletal reorganisation and caspases.

Adult↗
PubMed2000

Bidirectional supply of glutamine maintains enterocyte ATP content in the in vitro using chamber model.

Glutamine is the principal energy source for enterocytes, but it is not known whether parenteral or enteral supplementation is most beneficial to gut integrity. The aim of this study was to evaluate the effects of glutamine in uni- or bidirectional supply on the viability of intestinal mucosa of starved rats during incubation in Ussing chambers. Segments of jejunum from rats starved for 48 h were randomly mounted in Ussing chambers with three nutrient solutions: Krebs buffer without glutamine; 6 mM glutamine added to the mucosal side; 6 mM glutamine added to the mucosal side and 0.6 mM glutamine to the serosal side. ATP content of the mucosa, electrophysiology, and 51Cr-ethylenediaminetetraacetate (EDTA) permeability were studied during 180 min of incubation. The addition of glutamine to both sides of the stripped mucosa improved ATP levels compared to the Krebs solution (P < 0.05), and the addition of glutamine resulted in an increase in short circuit current (P < 0.05). No significant differences were seen in 51Cr-EDTA permeability or epithelial electrical resistance. Glutamine supplementation to both the luminal and serosal side in the Ussing chamber was more effective than luminal glutamine only in maintaining ATP levels of intestinal mucosa. Bidirectional supplementation of glutamine might improve intestinal energy metabolism and viability in in vitro studies.

Adenosine Triphosphate↗
PubMed2000

MHC expression in fragment and full-thickness allogeneic embryonic retinal transplants.

BACKGROUND: The study was carried out to evaluate the expression of major histocompatibility complex (MHC) molecules in retinal transplants with different tissue integrity. METHODS: Twelve adult rabbits received an allogeneic subretinal neuroretinal transplant, in the form of either fragmented embryonic cells or a complete full-thickness embryonic retina. A controlled transvitreal approach was used for both transplantation types. The grafts were examined histologically after 31 or 49 days with hematoxylin and eosin staining and immunohistochemical analysis of MHC class I and class II expression. RESULTS: All five fragment transplants developed into rosettes. Two of them displayed MHC class I-labeled cells, and four MHC class II-labeled cells. The cells were concentrated on the scleral side of the graft, and there was also a marked increase of labeled cells in the choroid. MHC labeling was often associated with defects in the retinal pigment epithelium. Six of the seven full-thickness grafts displayed a laminated morphology with well-developed retinal layers. The seventh consisted of rosettes. None of these grafts displayed MHC class I- or class II-labeled cells. CONCLUSIONS: The findings suggest that host immune response against fragmented and intact neuroretinal grafts is different, indicating tissue integrity as one factor affecting graft-host immune interactions. The absence of immune response in full-thickness grafts is encouraging and important in the struggle to find therapies for retinal degenerative disease.

Animals↗
PubMed2000

Central retinal artery occlusion in a patient homozygous for factor V Leiden.

PURPOSE: To report an association between central retinal artery occlusion and homozygosity for factor V Leiden. METHOD: Case report. RESULTS: A 48-year-old woman with sudden loss of visual acuity in her right eye caused by a central retinal artery occlusion showed abnormal resistance to activated protein C and was homozygous for the factor V Leiden gene. CONCLUSION: Activated protein C resistance may be a risk factor for central retinal artery occlusion in young adults.

Activated Protein C Resistance↗
PubMed2000

A comparison of results in middle-aged and young patients after anterior cruciate ligament reconstruction.

The aim of this retrospective study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction in middle-aged and young patients. From our database (including 604 patients with a follow-up rate of 95%), we extracted all the patients over 40 years of age (group A, n = 30) and compared them with a group of patients from the same material, aged between 20 and 24 years (group B, n = 37). The groups were comparable in terms of the male:female ratio and surgical techniques. The follow-up was performed by independent observers. The median follow-up period was 31 months (range, 22 to 60 months) in group A and 38 months (24 to 60 months) in group B (P =.014). Before injury, the Tegner activity level was 6 (4-9) in group A and 9 (4-9) in group B (P <.001). At follow-up, the Tegner activity level was 5 (3-9) in group A and 6 (3-9) in group B (P =.032). At the follow-up, there was no difference in terms of the Lysholm score, which was 91 (37-100) and 89 (38-100) points in group A and group B, respectively. Using the IKDC evaluation system, 10 patients (33%) were classified as normal, 12 (40%) as nearly normal, 6 (20%) as abnormal, and 2 (7%) as severely abnormal in group A, compared with 8 (22%) normal, 18 (48%) nearly normal, 10 (27%) abnormal, and 1 (3%) severely abnormal in group B (NS). The 1-leg hop quotient was 90% (52-167) in group A and 93% (70-118) in group B (P =.056). The KT-1000 measurement showed an anterior side-to-side laxity difference of 2.0 mm (-4 to 8.5 mm) in group A and 2.0 mm (-2.5 to 8.0 mm) in group B (not significant). The middle-aged patients were subjectively more pleased with the results than the younger patients. There were no differences in either early or late complications between the groups. At the index operation, 11 of 30 patients (37%) in group A and 1 of 37 (3%) in group B had cartilage lesions or degenerative changes (P <.001). Age does not appear to disqualify middle-aged patients with symptomatic ACL tears from undergoing reconstruction.

Adult↗
PubMed2000

The 30-Hz flicker cone ERG for monitoring the early course of central retinal vein occlusion.

PURPOSE: Investigation of the full-field ERG (electoretinography) within 24 hours after the onset of symptoms in central retinal vein occlusion, and repeated examination within the following days and weeks. METHODS: Seven patients with central retinal vein occlusion were examined with full-field ERG within less than 24 hours after the onset of their symptoms and every second to third day during the first 3 weeks. They were then followed for a period of time of six months. RESULTS: The amplitudes as well as the implicit times in the 30 Hz flicker ERG changed considerably within the first three weeks. In the three patients who developed rubeosis, the cone b-wave implicit times as well as the amplitudes were altered considerably. In the patients that did not develop rubeosis, the cone b-wave implicit times as well as the amplitudes in the 30 Hz flicker ERG were more stable. CONCLUSION: The full-field cone ERG reflects the retinal function and the ERG parameters change considerably during the first weeks after the onset of the central retinal vein occlusion. The 30 Hz flicker ERG gives important information concerning the early development of the disease. The optimal time to do a predictive ERG could be after three weeks.

Aged↗
PubMed2000

Hyperhomocysteinemia and the MTHFR C677T mutation in central retinal vein occlusion.

BACKGROUND: Hyperhomocysteinemia is a factor that predisposes to thrombosis, and the C677T mutation in methylene-tetrahydrofolate reductase (MTHFR) is known to give increased plasma homocysteine. We wanted to investigate if these factors were overrepresented in a group of patients with central retinal vein occlusion. METHODS: 116 patients with a history of central retinal vein occlusion were examined for the presence of hyperhomocysteinemia and the MTHFR C677T mutation. RESULTS: Compared to the control groups, there was no significant increase, neither in plasma homocysteine nor in the frequency of the MTHFR C677T mutation in the patients. Even when we looked selectively at the young patients, age less than 50 years, no difference could be detected. CONCLUSION: It seems that neither hyperhomocysteinemia nor the MTHFR C677T mutation is an important risk factor for the aetiology of central retinal vein occlusion.

Adult↗
PubMed2000

No effect of bolus glutamine supplementation on the postresectional adaptation of small bowel mucosa in rats receiving chow ad libitum.

OBJECTIVE: Early postoperative enteral feeding has been reported to stimulate intestinal mucosa proliferation. Dietary components influence the intestinal adaptive response after resection and glutamine is a preferential nutrient to enterocytes. The purpose of this study was to evaluate the effects of bolus glutamine supplementation on intestinal adaptation. METHODS: Male Wistar rats underwent a 65% small bowel resection. The rats were divided into three groups receiving glutamine 2 g/kg/day, isonitrogenous glycine or saline by gavage for 10 days. All the rats were provided with ordinary rat chow ad libitum. Sampling was done 10 days after resection. Animals fed ordinary rat chow without surgery or specific treatment served as control. RESULTS: Mucosal wet weight, DNA, RNA, protein contents and sucrose activity, as well as villus height increased in the ileal remnant. No significant differences in any of these parameters or body weight could be found between the three groups. CONCLUSION: Postoperative enteral bolus glutamine supplementation at a dose of 2 g/kg b.w. did not enhance the adaptation of the residual intestine 10 days after massive intestinal resection in the rat.

Adaptation, Physiological↗