PubMed Health⌕ Search

Biomedical subjects

S Persson

Publications and source records attributed to S Persson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Cardiovascular, respiratory and metabolic effects of interval training at VLA4.

The purpose of this study was to determine if training with short intervals at the velocity producing a lactate level of 4 mmol/l (VLA4) is sufficient to induce adaptations and better exercise tolerance. Five Standardbred mares (4-8 years) were interval trained on a treadmill 3 days a week for 12 weeks and subsequently detrained for 4 weeks. Standardized exercise tests were performed before, during and after the training period and muscle biopsies were taken. Measurements were made of heart rate, oxygen consumption, stride frequency, blood volume and blood lactate. Plasma volume was reduced after 2 weeks of training but then increased to the approximate pre-training value throughout the remaining training and post-training periods. No change was detected in the total cell volume whereas the total blood volume varied in consequence with the plasma volume variation. A significant reduction in heart rate response to exercise was seen after 4 weeks of training. VLA4 increased after 2 weeks of training and remained higher than the baseline value during the rest of the training period. Consequently, the blood lactate at 8 m/sec was decreased compared to baseline concentration after 8 and 12 weeks of training. The post-training VLA4 did not differ significantly either from the end of training or from the pre-training value. Mass specific oxygen consumption (VO2-200/BW) at V200 increased with training and decreased with detraining. The respiratory quotient at a velocity of 8 m/sec decreased from 1.18 +/- 0.02 before training to 1.07 +/- 0.02 (P < 0.05) at the end of training. No changes were found in muscle histo- or biochemical parameters. The results indicate that training at VLA4 is sufficient to cause adaptational changes in exercise tolerance related parameters.

Animals↗
PubMed1995

Calcitonin gene related peptide gene expression in collagen-induced arthritis.

Changes in calcitonin gene related peptide (CGRP) gene expression in spinal motoneurons and dorsal root ganglia (DRG) of rats subjected to collagen II induced arthritis (CIA) were evaluated by semiquantitative in situ hybridization. The effects of systemic treatment with the corticosteroid budesonide on basal CGRP expression and on changes under inflammatory conditions were examined. CIA caused a significant increase in CGRP mRNA levels in DRG. Budesonide reduced the constitutive CGRP mRNA levels in DRG, compared with untreated control rats, and reversed the CIA-induced increase. In contrast, CIA caused a marked decrease of CGRP mRNA levels in motoneurons. Budesonide had no effect on constitutive CGRP mRNA levels in motoneurons and attenuated the decrease in CGRP mRNA levels in motoneurons of rats subjected to CIA. Thus, peripheral inflammation and systemic corticosteroids have differential effects on CGRP expression in sensory and motor neurons. This may be relevant for the pathophysiology and pharmacotherapy of chronic inflammatory pain and motor dysfunction in chronic arthritis.

Animals↗
PubMed1994

Spinal prodynorphin gene expression in collagen-induced arthritis: influence of the glucocorticosteroid budesonide.

Changes in the spinal expression of the opioid precursor and prodynorphin, which has been implicated in the response to peripheral inflammation, were examined with semi-quantitative in situ hybridization histochemistry in rats subjected to collagen II-induced arthritis. The effects of glucocorticosteroid treatment on the basal and inflammation-induced prodynorphin expression were evaluated. Collagen II-induced arthritis caused a 16-fold increase in prodynorphin mRNA levels which comprised all neurons expressing low levels under normal conditions. In the superficial dorsal horn, one group of neurons of a large size reacted with a dramatic increase of prodynorphin mRNA, while another group of small neurons exhibited a moderate elevation of prodynorphin mRNA levels. In the deep dorsal horn of arthritic rats, most prodynorphin neurons were large and showed high prodynorphin mRNA levels. Systemic treatment with the glucocorticosteroid budesonide attenuated the arthritis-induced increase of prodynorphin mRNA expression in a topospecific manner. The budesonide-induced reduction of prodynorphin mRNA levels was more pronounced in the deep dorsal horn than in the superficial dorsal horn. Budesonide treatment of control animals caused a small, but significant increase in prodynorphin mRNA levels in the superficial laminae I/II without affecting prodynorphin mRNA levels in the deep dorsal horn. The degree of arthritis correlated closely with spinal prodynorphin mRNA levels. The tight correlation between severity of arthritis and prodynorphin mRNA levels in non-treated and corticosteroid-treated arthritic rats suggests that spinal prodynorphin expression is a good parameter for the evaluation of the influence of peripheral inflammation and of the efficacy of analgesic/anti-inflammatory drugs in its treatment. Opposite effects of budesonide on basal and inflammation-induced prodynorphin expression may involve a spinal site of action in addition to peripheral anti-inflammatory mechanisms. We suggest that the collagen II-induced arthritis in the rat is an excellent model for human rheumatoid arthritis allowing for the study of molecular plasticity of anti-inflammatory and anti-nociceptive drug action at different levels of the neuroaxis.

Administration, Topical↗
PubMed1994

Improved exercise hemodynamic status in dilated cardiomyopathy after beta-adrenergic blockade treatment.

OBJECTIVES: This study was performed to investigate exercise hemodynamic status in a double-blind, placebo-controlled trial and was a substudy in the Metoprolol in Dilated Cardiomyopathy Trial. BACKGROUND: Previous open studies have shown beneficial effects on exercise hemodynamic status after beta-adrenergic blocking agent therapy in patients with congestive heart failure. METHODS: The study included 41 patients with idiopathic dilated cardiomyopathy with ejection fraction < 0.40 (metoprolol, 20 patients; placebo, 21 patients) whose hemodynamic status was investigated at rest and during supine submaximal exercise, at baseline and after 6 and 12 months of treatment. Myocardial metabolism was evaluated in a subset of 19 patients. RESULTS: Metoprolol-treated patients responded favorably, as expressed by improved exercise cardiac index ([mean +/- SD] placebo 4.8 +/- 1.6 to 4.7 +/- 1.8 liters/min per m2, metoprolol 4.3 +/- 1.1 to 5.4 +/- 1.9 liters/min per m2, p = 0.0001) and stroke work index (placebo 44 +/- 20 to 41 +/- 27 g.m/m2, metoprolol 35 +/- 16 to 58 +/- 28 g.m/m2, p < 0.0001). Exercise systolic arterial pressure increased (placebo 161 +/- 25 to 151 +/- 23 mm Hg, metoprolol 155 +/- 29 to 165 +/- 37 mm Hg, p = 0.0003) as well as exercise oxygen consumption index (placebo 463 +/- 194 to 474 +/- 232 ml/min per m2, metoprolol 406 +/- 272 to 507 +/- 298 ml/min per m2, p = 0.045). There was a significant increase in exercise duration in the metoprolol group (63 +/- 38 s) compared with the placebo group (-24 +/- 42 s) (p = 0.01). Net myocardial lactate extraction increased in the metoprolol group, suggesting less myocardial ischemia (placebo 17 +/- 22 to 9.5 +/- 6.4 mmol/min, metoprolol -32 +/- 100 to 42 +/- 45 mmol/min, p = 0.03). Peripheral levels of norepinephrine tended to decrease at rest and during exercise, whereas myocardial net spillover was unchanged. CONCLUSIONS: Metoprolol improved hemodynamic status in patients with dilated cardiomyopathy at rest and had a more pronounced effect during exercise. These positive effects were achieved along with improved or stable myocardial metabolic data.

Analysis of Variance↗
PubMed1994

Changed blood rheology in patients with idiopathic dilated cardiomyopathy.

Rheologic properties of blood were studied in 8 patients with dilated cardiomyopathy (DCM) and in 10 healthy subjects. Whole-blood viscosity was measured at four different shear rates, by means of a computer-controlled rotational viscometer. The patients had significantly higher blood viscosity at all shear rates, both at their natural hematocrits and after an in vitro adjustment of sample hematocrits to 45%. Erythrocyte filterability (5 microns pore size) was significantly lower, fibrinogen concentration significantly higher, and HDL-cholesterol concentration significantly lower in the patient group. No significant differences were found regarding hematocrit, mean corpuscular volume, hemoglobin concentration, leukocyte count and filterability (8 microns pore size), plasma viscosity, and total cholesterol concentration. The measured hemorheologic abnormalities may contribute to the previously reported reduction of coronary blood flow reserve in DCM patients and to myocardial microcirculatory disturbances, which have been suggested as a cause for DCM.

Adult↗
PubMed1994

Protostrongylidae in Cervidae and Ovibos moscatus: a clustering based on isoelectric focusing on nematode body proteins.

Isoelectric focusing for protein separation and evaluation by Unweighted Pair Group Method with Arithmetic averages (UPGMA) clustering was tested as an alternative to a morphological approach to taxonomical studies of the family Protostrongylidae and the genus Elaphostrongylus. These analyses revealed a close relationship among first stage protostrongylid larvae from roe deer, muskoxen and Varestrongylus alces first stage larvae. Furthermore, first stage larvae collected from moose faeces and adult Elaphostrongylus in moose were found related. Adult Elaphostrongylus in moose and reindeer maintained their separate taxonomical status.

Animals↗
PubMed1993

Safety of transvenous right ventricular endomyocardial biopsy guided by two-dimensional echocardiography.

A total of 231 endomyocardial biopsy procedures performed in 74 consecutive patients were evaluated to compare the incidence and nature of complications in procedures guided by fluoroscopy versus those guided by echocardiography. Sixty biopsy procedures were guided by fluoroscopy and 171 by two-dimensional echocardiography. The right interventricular septum was the target site for biopsy sampling in all patients. Clinical signs of myocardial perforation occurred during one (1.7%) procedure guided by fluoroscopy versus two (1.2%) procedures guided by echocardiography. Two cases of interventricular septal perforation were visualized during the echo-guided procedures. The biopsy specimens were judged to be inadequate for diagnosis in 2.2% of the biopsy procedures, all of which were guided by fluoroscopy. The number of samples obtained during a procedure guided by fluoroscopy was lower (mean 2.3 +/- 1.6) (mean +/- 1 SD) than that taken during a procedure guided by echocardiography (mean 4.0 +/- 1.2). Epicardial or pericardial tissue was present in 5.8% of the samples obtained under fluoroscopic guidance, versus 0.7% of the samples obtained using echocardiography (p = 0.0003). It is concluded that although echocardiography seems to provide more accurate and safer guidance for the positioning of the bioptome toward the septum, the presence of epicardium or pericardium in 0.7% of the samples indicates that inadvertent sampling from the right ventricular free wall cannot be avoided.

Adolescent↗
PubMed1993

L-iduronate-rich glycosaminoglycans inhibit growth of normal fibroblasts independently of serum or added growth factors.

The effects of various glycosaminoglycans (GAGs) on the growth rate of normal fibroblasts and a fibrosarcoma cell line (HT 1080) were examined. Cells were grown in 96-well microplates in the absence or presence of serum mitogens, epidermal (EGF), platelet-derived (PDGF), acidic fibroblast (aFGF), or basic fibroblast growth factor (bFGF). Cell number was measured by using crystal violet to stain cell nuclei (Westergren-Thorsson, G., Onnervik, P.-O., Fransson, L.-A., and Malmström, A. J. Cell. Phys. 147, 523-530, 1991) and also by using a Coulter counter. In the presence of serum mitogens, L-iduronate (IdoA)-rich GAGs, such as dermatan sulfate, heparin, and highly sulfated heparan sulfate, inhibited proliferation of normal cells (25-35%), whereas HT 1080 cells were unaffected or slightly stimulated. Ham's F-12 supplemented with insulin and transferrin but without growth factors was able to support growth of both cell types. Under these conditions, the IdoA-rich GAGs still suppressed growth of normal cells (40-55%), whereas HT 1080 cells again responded poorly. When growth factors were added proliferation of normal fibroblasts was further stimulated, EGF being the most effective. In the presence of either EGF, PDGF, or bFGF, IdoA-rich GAGs had a sustained inhibitory effect on normal fibroblasts (30-50% at concentrations at or above 10 micrograms/ml). However, in the presence of aFGF, both IdoA-rich and IdoA-poor heparan sulfates enhanced growth (nearly twofold after prolonged exposure) suggesting a stabilization of this growth factor. In general, IdoA-rich GAGs appear to inhibit proliferation of normal cells irrespective of the type of growth factor used. Therefore, GAGs are likely to act directly on cell-derived regulatory components, either before or after internalization. As fibrosarcoma cells were much less sensitive to growth inhibition, they may contain altered receptors for GAGs.

Blood Proteins↗
PubMed1993

Cerebrospinal fluid dynorphin-converting enzyme activity is increased by voluntary exercise in the spontaneously hypertensive rat.

The activity in cerebrospinal fluid (CSF) of dynorphin-converting enzyme (DCE) has been studied after voluntary exercise in the spontaneously hypertensive (SH) rat. The exercise consisted of spontaneous running in wheels for 4-5 weeks and the average running distance during the last two weeks was 4.0 km/24h. CSF samples were obtained under anaesthesia from the cisterna magna after penetration of the atlanto-occipital membrane. DCE transforms the members of the dynorphin family of opioid peptides into Leu-enkephalin-Arg6. In the present investigation a radioimmunoassay was used for quantitation of Leu-enkephalin-Arg6 release from dynorphin A1-17 and dynorphin B1-13. The rats that were running had a DCE activity (vs. both substrates) in CSF that was approximately 6-12 times higher than in animals not given the running opportunity. A statistically significant correlation between the two prodynorphin-derived substrate peptides was found in terms of DCE activity. We therefore propose that a single enzyme activity may be responsible for the hydrolysis of dynorphin B1-13 and dynorphin A1-17. Furthermore, a significant correlation was also found between running activity and DCE activity 12-14 h before the CSF was withdrawn. Besides measurement of DCE activity by radioimmunoassay, the formation of Leu-enkephalin-Arg6 was identified by reversed-phase micro-column liquid chromatography and plasma desorption mass spectrometry. The experiment shows that voluntary exercise affects opioid peptidergic mechanisms.

Amino Acid Sequence↗
PubMed1993

Chronic administration of morphine decreases level of dynorphin A in the rat nucleus accumbens.

The effect of chronically administered morphine on the levels of dynorphin A in distinct regions of the brain (including medial frontal cortex, olfactory tubercule, nucleus accumbens, dorsal and medial striatum), was determined in male Sprague-Dawley rats. The drug was delivered through a subcutaneously implanted Azlet miniosmotic pump over a period of 5 days. The concentration of peptide was probed by radioimmunoassay, following pre-separation of tissue extracts by reversed phase separation on a SepPak C-18 cartridge. The result showed that the level of dynorphin A remained unaltered in all regions studied immediately before (tolerance) and 20 hr after (withdrawal) the pump was removed. A significant decrease in the level of dynorphin was found in the n. accumbens 48 hr (abstinence) after removal of the pump. It is suggested that previously observed changes in the reward system during abstinence may be connected with dynorphinergic neurones in the limbic system.

Animals↗
PubMed1993

Chemotaxis and degranulation of polymorphonuclear leukocytes in the presence of sulfide.

In polymicrobial infections such as periodontal disease, the polymorphonuclear leukocytes (PMN) may have to work in the absence of oxygen and in the presence of significant levels of hydrogen sulfide. There are conflicting results reported on the chemotactic capacity of PMN under anaerobic conditions. It is not known whether PMN are able to migrate and release the contents of their granules in the presence of sulfide. PMN were exposed to various levels of sulfide and their chemotaxis and degranulation were studied when they were stimulated with N-formyl-methionyl-leucyl-phenylalanine or zymosan-activated serum. Chemotaxis was evaluated with the agarose method. The release of granule markers, lactoferrin and myeloperoxidase, was evaluated with enzyme-linked immunosorbent assay. PMN had similar capacity for chemotaxis under aerobic and anaerobic conditions. The migration of PMN was only to a minor extent inhibited by 1-2 mM sulfide. The release of lactoferrin and myeloperoxidase was the same under aerobic and anaerobic conditions and was not significantly influenced by sulfide. PMN seem to be very well suited to defend the tissue against bacteria under the harsh conditions prevailing in the periodontal pocket.

Anaerobiosis↗
PubMed1993

Blood viscosity during long-term treatment with ticlopidine in patients with intermittent claudication. A double-blind study.

The aim was to test within a randomized, double-blind trial whether the antiaggregant drug ticlopidine might reduce blood viscosity as has been claimed. Sixteen patients with intermittent claudication were studied before and after three years of treatment with ticlopidine, 500 mg/day, or placebo. At baseline, the viscosity values were significantly higher as compared with a reference group of healthy subjects. Whole-blood viscosity, measured at four different shear rates at hematocrit adjusted to a standard 40%, decreased significantly at follow-up, with no difference between ticlopidine treatment and placebo. Hematocrit showed a slight increase in the placebo group. The viscosity parameters were unrelated to lower limb blood flow variables, ankle/brachial index, and walking distances. The mechanism behind the overall decrease in whole-blood viscosity is obscure but could possibly be explained by lifestyle changes. Smoking habits were, however, unaltered. Since plasma viscosity remained increased, it might indicate that some erythrocyte factor, notably red cell aggregability and deformability, had improved. It is concluded that ticlopidine had no long-term effect on blood viscosity.

Aged↗
PubMed1992

Decreased cerebrospinal fluid neuropeptide-converting enzyme activity in monoarthritic rats.

The activity in rat cerebrospinal fluid (CSF) of dynorphin-converting enzyme (DCE) and substance P endopeptidase (SPE) was determined in control animals and in rats with monoarthritis. Enzymatic activities were measured with specific radioimmunoassays toward the N-terminal products Leu-enkephalin-Arg6 and substance P1-7, respectively. A monoarthritis stable during weeks 2-6 post-injection was induced by injection (0.05 ml) into one joint with Freund's adjuvant. Both SPE and DCE were significantly decreased 15 days after the intraarticular injection. Despite the degree of arthritis that was sustained equally at four weeks after inoculation, both DCE and SPE were back to control levels at that time. It can therefore be concluded that arthritis from a single joint is sufficient to elicit changes in CSF convertase activities, and that these effects disappear between 2 and 4 weeks after injection, although the arthritis persists.

Animals↗
PubMed1992

Metastasizing gastric epithelioid leiomyosarcomas (leiomyoblastomas) in young individuals with long-term survival.

RESULTS. Four patients with metastasizing epithelioid leiomyosarcoma of the stomach, three females and one male (15, 20, 22, and 25 years of age, respectively), are reported. Two patients had recurrent tumors in the gastric remnant. Liver metastases occurred in all patients, three of whom had lymph node metastases; two had peritoneal metastases. The patients are alive at 17, 19, 27 and 48 years after the diagnosis was made and 17-27 years after the first demonstration of metastases. One woman had multiple chondromatous hamartomas of the lung. Operations were performed when the patients had symptoms and during periods of no symptoms, as directed by the second-look principle. One patient had 10 operations. None of the patients received adjuvant therapy. All three women have given birth to healthy children after metastases were diagnosed. Three of the primary tumors were large (10-20 cm) and multinodular, features that have been associated with unfavorable prognosis. The four primary tumors had a similar light microscopic appearance, characterized by moderate cell and nuclear pleomorphism and low mitotic activity, 0.03-0.1/mm2. Ultrastructurally, a network of intermediate filaments was found within the cytoplasm of the tumor cells corresponding to the immunohistochemical positivity for vimentin. The immunohistochemical findings (negative immunoreaction for desmin and alpha smooth-muscle actin) and the ultrastructural analysis produced no evidence of the production of smooth-muscle cell myofilaments. However, there were tumor cells with an abundance of mitochondria and a paucity of filaments, features that may be characteristic of epithelioid leiomyomatous tumors. In addition, immunohistochemical negativity for cytokeratins, epithelial membrane antigen, S-100 protein, neuron-specific enolase, and chromogranin militate against an epithelial or neuroectodermal cell differentiation. CONCLUSIONS. An awareness of this type of gastric leiomyosarcoma in children and young adults is of importance in making correct assessments of prognosis and choosing an active therapeutic approach. The biologic background to the clinical behavior of these metastasizing tumors remains an enigma. Additional studies are needed to elucidate the biology of these tumors.

Adolescent↗
PubMed1992

Decreased neuropeptide-converting enzyme activities in cerebrospinal fluid during acute but not chronic phases of collagen induced arthritis in rats.

We investigated the effects of collagen II-induced arthritis on two cerebrospinal fluid (CSF) enzymes converting dynorphin A and substance P (SP), namely dynorphin-converting enzyme (DCE) and substance P endopeptidase (SPE). The products generated by these enzymes are the bioactive fragments Leu-enkephalin-Arg6 and substance P, respectively. The strain used (DA rats) is very sensitive towards induction of arthritis. The collagen arthritis is a chronic autoimmune arthritis induced by native rat collagen type II (CII). Following intradermal injection of CII into the tailbase. CSF was sampled on day 21 (acute arthritis) and day 38 (chronic arthritis). Control rats were untreated because the strain used developed an acute and self-limited arthritis (adjuvant arthritis) when administered vehicle (i.e. incomplete Freund's adjuvant). The DCE activity was significantly lowered in the acute phase of arthritis (P less than 0.05) when analysed with two-factor analysis of variance (ANOVA). The enzyme converting SP (SPE) also showed a significant decrease in the acute phase of arthritis (P less than 0.05). These results demonstrate that both DCE and SPE are affected in the acute phase of arthritis. A functional role of these enzymes in processing pain-related neuropeptides is therefore implicated.

Acute Disease↗
PubMed1992

Hydrogen sulfide and methyl mercaptan in periodontal pockets.

A sensitive gas chromatographic method was developed to determine the amounts of volatile sulfur compounds in gingival fluid. Hydrogen sulfide was the predominant volatile sulfur compound and was detected in 61 out of 79 studied periodontal pockets. Methyl mercaptan was found in about 20% of the pockets. No other volatile sulfur compounds were detected. The highest concentration of hydrogen sulfide in gingival fluid was 1.9 mmol/liter, and of methyl mercaptan 0.16 mmol/liter.

Adult↗