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Biomedical subjects

S Pedersen

Publications and source records attributed to S Pedersen.

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

Acquired immunity to Trichuris suis infection in pigs.

Strong resistance to reinfection developed in pigs as a result of trickle inoculations with Trichuris suis (250 infective eggs twice weekly for 4 weeks). At challenge (4000 eggs) 8 weeks after the last trickle inoculation, we observed a 96% reduction in the mean number of established challenge worms in immunized (TRI/CHA) compared with non-immunized controls (CON/CHA) (74 v. 1753; P = 0.004). Moreover, the total faecal egg excretion was significantly lower in immunized pigs compared with controls (P = 0.0003). The trickle inoculations depressed pig weight gains over the 8-week course of immunization (P = 0.042). It was observed that a small number of pigs developed a weaker level of resistance, reflecting the importance of genetic determinants. The relevance of these data to the population biology of porcine and human whipworm infections is discussed.

Animals↗
PubMed2001

Assessing the effect of intranasal steroids on growth.

Several studies have evaluated the effects of childhood use of corticosteroids on growth. In short-term studies, the budesonide (BUD) metered dose inhaler and methylprednisolone (injection) had significant effects on lower-leg growth, whereas terfenadine did not. When two doses of BUD (nasal inhaler, 200 or 400 microg once daily) were compared with placebo, only the 400-microg dose had a significant effect on short-term growth. Intranasal mometasone furoate (MF) (100 and 200 microg) had no significant effect on short-term lower-leg growth. In intermediate studies of 1-year duration, intranasal beclomethasone dipropionate (84 microg twice daily) significantly affected growth rate, whereas in a separate study, 100 microg intranasal MF once daily did not. Long-term growth data come from retrospective studies of children with asthma. In these studies, no significant effect on growth has been demonstrated in children taking inhaled beclomethasone dipropionate or BUD. The reason for the discrepancy between intermediate and long-term studies is unclear and warrants further study. Variables in childhood growth including seasonal variations may make growth difficult to assess. However, because growth suppression has been reported in children receiving inhaled or intranasal corticosteroids, the lowest effective dose of drug with a low systemic absorption ratio should always be used. Overall, there appears to be no growth suppression with 100 microg intranasal MF used once daily in children.

Administration, Intranasal↗
PubMed2001

Release of heat, moisture and carbon dioxide in an aviary system for laying hens.

1. Production of total heat, divided into sensible and latent heat, together with carbon dioxide and animal activity were determined at different ambient temperatures under full-scale conditions in an aviary system with loose-housed laying hens. 2. Sensible heat production decreased approximately linearly with increasing ambient temperature and was lower during the day than at night. One explanation may be that some sensible heat produced by the hens was converted to latent heat by evaporation of moisture due to increased activity of the hens during the day (scratching in the bedding and drinking/waste water). 3. Latent heat production increased with increasing ambient temperature and was higher during the day than at night. This confirms that the hens, by agitating the bedding during the day and by spilling drinking water, transferred some sensible heat to latent heat by evaporation. 4. Total heat production decreased with increasing temperature because the hens by thermoregulation decreased their metabolism in order to maintain a constant body temperature. The difference between day and night values of total heat production was less pronounced than in the case of sensible and latent heat. In comparison with current guidelines the measurements showed a higher total heat production (22% higher at 20 degrees C). 5. There was a large diurnal variation in carbon dioxide production, closely correlated to measured animal activity; on average carbon dioxide production during the 12-h dark period was only 66% of the production during the day.

Animals↗
PubMed2001

Deaf pupils' reasoning about scientific phenomena: school science as a framework for understanding or as fragments of factual knowledge.

Many studies have been conducted on hearing pupils' understanding of science. Findings from these studies have been used as grounds for planning instruction in school science. This article reports findings from an interview study of how deaf pupils in compulsory school reason about phenomena in a science context. The results reveal that there is variation in the extent to which pupils use scientific principles for reasoning about science phenomena. For some pupils, school science seems to have little to offer as a framework for reasoning. The results also generate questions about the need in school instruction of deaf and hard-of-hearing pupils to consider the specific teaching and learning situations in a deaf environment.

Journal Article↗
PubMed2001

Exposure assessment and lung function in pig and poultry farmers.

OBJECTIVES: To describe the relation between spirometric findings and farming characteristics and variables of exposure to organic dust measured during work in animal buildings. Farmers have traditionally been described as having one of the most dangerous occupations, so a large scale study on European farmers was carried out. This is the report of the second part of that study. METHODS: 40 pig farmers in Denmark and 36 poultry farmers in Switzerland were chosen randomly and were assessed over 1 working day. RESULTS: Mean (SD) baseline spirometric results in pig farmers were higher than in poultry farmers (forced expiratory volume in 1 second (FEV(1)) (% of reference value) 108.3 (16.7) v 100.2 (14.2); p=0.04). Baseline lung function results were significantly associated with ventilation of the animal houses. Furthermore, temperature was related to spirometric findings in pig farmers. CONCLUSIONS: Ventilation of the animal house and temperature might influence respiratory morbidity in farmers.

Adult↗
PubMed2000

Effect of long-term treatment with inhaled budesonide on adult height in children with asthma.

BACKGROUND: Short-term studies have shown that inhaled corticosteroids may reduce the growth of children with asthma. However, the effect of long-term treatment on adult height is uncertain. METHODS: We conducted a prospective study in children with asthma to examine the effect of long-term treatment with inhaled budesonide on adult height. We report on 211 children who have attained adult height: 142 budesonide-treated children with asthma, 18 control patients with asthma who have never received inhaled corticosteroids, and 51 healthy siblings of patients in the budesonide group, who also served as controls. RESULTS: The children in the budesonide group attained adult height after a mean of 9.2 years of budesonide treatment (range, 3 to 13) at a mean daily dose of 412 microg (range, 110 to 877). The mean cumulative dose of budesonide was 1.35 g (range, 0.41 to 3.99). The mean differences between the measured and target adult heights were +0.3 cm (95 percent confidence interval, -0.6 to + 1.2) for the budesonide-treated children, -0.2 cm (95 percent confidence interval, -2.4 to +2.1) for the control children with asthma, and +0.9 cm (95 percent confidence interval, -0.4 to +2.2) for the healthy siblings. The adult height depended significantly (P<0.001) on the child's height before budesonide treatment. Although growth rates were significantly reduced during the first years of budesonide treatment, these changes in growth rate were not significantly associated with adult height. CONCLUSIONS: Children with asthma who have received long-term treatment with budesonide attain normal adult height.

Administration, Inhalation↗
PubMed2000

[Will the use of still image electronic referrals save costs?].

BACKGROUND: The use of still images in an electronic referral makes it possible for patients with uncomplicated skin disorders to receive treatment at their local health clinic by their own physician. The aim of this study was to analyse whether investing in technology to forward still images via telemedicine is cost-effective and to assess how many municipalities in the counties of Troms and Finnmark that have a sufficient workload to reach this requirement. MATERIAL AND METHODS: The additional costs of using still images were compared to patient travel costs to the University Hospital of Tromsø. RESULTS: The results showed that whether the use of still image telemedicine is cost-effective or not, depends on distance and annual workload. Given the assumption in this study, 18 out of 44 municipalities have a sufficient number of patients with a dermatological problem to make telemedicine cost-effective. INTERPRETATION: Less than half of the municipalities in the two northernmost counties have an efficiency potential in using still images. However, telemedicine may be justified because it save time for patients and it increases equal access to care.

Cold Climate↗
PubMed2000

Thermodynamics of heat-shock response.

Production of heat-shock proteins is induced when a living cell is exposed to a rise in temperature. The heat-shock response of protein DnaK synthesis in E.coli for temperature shifts T-->T+DeltaT and T-->T-DeltaT is measured as a function of the initial temperature T. We observe a reversed heat shock at low T. The magnitude of the shock increases when one increases the distance to the temperature T0 approximately 23 degrees C, thereby mimicking the nonmonotonous stability of proteins at low temperature. This suggests that stability related to hot as well as cold unfolding of proteins is directly implemented in the biological control of protein folding.

Escherichia coli↗
PubMed2000

[Malignant neuroleptic syndrome. A review of epidemiology, risk factors, diagnosis, differential diagnosis and pathogenesis of MNS].

Neuroleptic malignant syndrome (NMS) is a rare, potentially life-threatening disorder that results from the use of neuroleptics. NMS was first recognised as a complication of dopamine receptor antagonists characterized by extrapyramidal disturbances, hyperthermia, muscle rigidity, autonomic instability, mental status changes and elevated serum creatine kinase levels. Concepts of NMS have changed because medications other than classic neuroleptic drugs have been implicated as triggering agents. The incidence of NMS is about 0.2% with a mortality between 4-30%, which may be diminished by treatment. The neurochemical key features in all these conditions probably result from disruption of the dopamine system in the brain and the effects of neuroleptics on muscle. Recognition of NMS is the most important step in its management by discontinuation of the causative drugs and applying supportive care and therapeutic measures. Specific therapeutic measures include the application of dopamine receptor agonists, e.g. dantrolene and use of benzodiazepines. The differential diagnosis of NMS comprises an extensive list of disorders presenting with fever and with muscle rigidity. Neuroleptics may be reintroduced in the majority of patients by using an atypical neuroleptic drug such as clozapine.

Adolescent↗
PubMed2000

Cell shrinkage is essential in lysophosphatidic acid signaling in Ehrlich ascites tumor cells.

The present study aimed at elucidating the initial intracellular lysophosphatidic acid (LPA)-induced signaling events, in order to investigate the sequence in which LPA affects the intracellular concentration of free, cytosolic Ca(2+), [Ca(2+)](i), ion channels, the F-actin cytoskeleton, cell volume and the Na(+)/H(+) exchanger. We found that stimulation of Ehrlich cells with LPA induced a transient, concentration-dependent increase in [Ca(2+)](i), which is due to Ca(2+) release from intracellular Ins(1,4,5)P(3)-sensitive stores as well as an influx of Ca(2+). The EC(50) values for LPA-induced Ca(2+) mobilization were estimated at 0.03 nm and 0.4 nm LPA in the presence and absence of extracellular Ca(2+), respectively. The LPA-induced increase in [Ca(2+)](i) resulted in (i) co-activation of Ca(2+)-activated, charybdotoxin (ChTX)-sensitive K(+) and niflumic acid-sensitive Cl(-) currents; (ii) a subsequent cell shrinkage and increased polymerization of F-actin, and (iii) activation of a Na(+)/H(+) exchange, resulting in a concentration-dependent intracellular alkalinization. The EC(50) value for the LPA-induced rate of alkalinization was estimated at 0. 37 nm LPA. When cell shrinkage was prevented, the LPA-induced activation of the Na(+)/H(+) exchanger was impaired. In conclusion, the initial signaling events induced by LPA involves activation of volume regulatory mechanisms.

Actins↗
PubMed2000

Human and mouse mitochondrial orthologs of bacterial ClpX.

We have determined the cDNA sequence and exon/intron structure of the human CLPX gene encoding a human ortholog of the E. coli ClpX chaperone and protease subunit. The CLPX gene comprises 14 exons and encodes a 633-amino acid-long precursor polypeptide. The polypeptide contains an N-terminal putative mitochondrial transit peptide, and expression of a full-length ClpX cDNA tagged at its C-terminus (Myc-His) shows that the polypeptide is transported into mitochondria. FISH analysis localized the CLPX gene to human Chromosome (Chr) 15q22.1-22.32. This localization was refined by radiation hybrid mapping placing the CLPX gene 4.6 cR distal to D15S159. Murine ClpX cDNA was sequenced, and the mouse Clpx locus was mapped to a position between 31 and 42 cM offset from the centromere on mouse Chr 9. Experimental observations indicate the presence of a pseudogene in the mouse genome and sequence variability between mouse ClpX cDNAs from different strains. Alignment of the human and mouse ClpX amino acid sequences with ClpX sequences from other organisms shows that they display the typical modular organization of domains with one AAA(+) domain common to a large group of ATPases and several other domains conserved in ClpX orthologs linked by non-conserved sequences. Notably, a C-4 zinc finger type motif is recognized in human and mouse ClpX. This motif of so far unknown function is present only in a subset of the known ClpX sequences.

ATPases Associated with Diverse Cellular Activitie↗
PubMed2000

Comparative study designs and what they show.

Normally an increase in lung deposition leads to an improved clinical effect. An increase in clinical effect should be substantial (two-fold or greater) in order to be detected even in carefully conducted clinical trials. Further studies are needed in order to define the best clinical study designs with which to detect differences between different inhalers.

Anti-Asthmatic Agents↗
PubMed2000

Hypotonic cell swelling induces translocation of the alpha isoform of cytosolic phospholipase A2 but not the gamma isoform in Ehrlich ascites tumor cells.

We demonstrate that two isoforms of the cytosolic phospholipase A2, cPLA2alpha and cPLA2gamma, are present in Ehrlich ascites tumor cells. Both enzymes are almost uniformly distributed throughout the cells under control conditions, as visualized by laser-scanning confocal microscopy. Stimulation by either hypotonic cell swelling or addition of the Ca2+ ionophore A23187 results in translocation of cPLA2alpha, but not cPLA2gamma, to the nucleus, where it forms hot-spot-like clusters. Our group previously showed that release of radioactively labeled arachidonic acid, incorporated into the phospholipids of Ehrlich cells, was immediately and transiently increased on hypotonic cell swelling [Thoroed, S.M., Lauritzen, L., Lambert, I.H., Hansen, H.S. & Hoffmann, E.K. (1997) J. Membr. Biol. 160, 47-58]. We now demonstrate that arachidonic acid is released from the nuclear fraction following hypotonic exposure. Stimulation of Ehrlich cells with A23187 also leads to an increase in arachidonic acid release from the nucleus. However, as hypotonic cell swelling is not accompanied by any detectable increase in intracellular concentration of free cytosolic Ca2+ ([Ca2+]i), stimulus-induced translocation of cPLA2alpha can also occur without elevation of [Ca2+]i. The stimulus-induced translocation of cPLA2alpha appears not to be prevented by inhibition of mitogen-activated protein (MAP) kinase activation, p38 MAP kinase, tyrosine kinases and protein kinase C, hence, phosphorylation is not crucial for the stimulus-induced translocation of cPLA2alpha. Disruption of F-actin did not affect the translocation process, thus, an intact F-actin cytoskeleton does not seem to be required for translocation of cPLA2alpha.

Animals↗
PubMed2000

Experimental infection of pigs with three dose levels of Trichuris suis.

The objective of the study was to follow the course of Trichuris suis infection in pigs given infective eggs at low (400 eggs), medium (4,000 eggs) and high inoculation dose (40,000 eggs), respectively. Interestingly, despite a 100-fold difference in dose level no significant difference was found in either blood parameters, total faecal egg excretion, fecundity or worm burdens at necropsy 12 weeks post inoculation. The highest and lowest median faecal egg output was found in the medium and high dose group, respectively. With increasing dose level, worm size, establishment and prevalence of T. suis positive pigs decreased while worms were dislocated aborally. In addition there was a highly significant correlation between female worm burden and faecal egg excretion.

Animals↗
PubMed2000

Prevalence of musculoskeletal symptoms among aluminium workers.

The aim of this study was to determine the prevalence of musculoskeletal symptoms (MSS) in workers in the aluminium industry, and to test the relationship with work by using the duration of employment as a measure of exposure. A total of 5654 workers (92%) answered a questionnaire. Operators, who were more exposed to physically demanding work, showed a greater incidence of MSS than did office workers. Among operators, the duration of employment was significantly correlated with MSS in nine out of ten areas of the body, when adjusted by multiple regression analyses for age, gender, height, weight, smoking and physical activity. Among office workers this relationship was weaker and was significant only for neck and lower back areas. The higher prevalence of MSS among operators and the association between their duration of employment and MSS suggests that a higher risk of MSS is related to the working environment.

Adolescent↗