Exploring denitrifying communities in the environment

Denitrifiers are aerobically respiring bacteria that under anoxic conditions have the ability to switch to anaerobic respiration, so that nitrate and nitrite are stepwise reduced to nitric oxide, nitrous oxide and dinitrogen. Denitrifiers are a very diverse functional group with members from almost all phylogenetic bacterial groups. One aim of this thesis was to re-evaluate published primers targeting the functional genes, nirS, nirK and nosZ, encoding different enzymes in the denitrification pathway. New primer combinations for nirS and nosZ were designed, whereas the existing primers for nirK still seemed satisfactory. It was possible to PCR-amplify nirS genotypes from soil samples using the new nirS primer pair. In addition, denaturing gradient gel electrophoresis was introduced as a fingerprinting method for nirK- and nosZ-denitrifiers. The methods developed in this initial project were then used to study denitrifying communities in two environments where denitrification is especially important from a human perspective. In the first, methanol and ethanol were added to a wastewater treatment plant with an activated sludge process to increase the denitrification rate. As a result of the additions of external carbon sources the denitrifying communities altered their metabolic function, and specific nirS- and nirK-denitrifiers developed. In the second project, the nirK-denitrifiers were used as a model community to investigate the toxicity of the heavy metal silver to soil denitrifiers. The use of silver is increasing because of its well-known antimicrobial effects, and this may lead to increased environmental contamination. The addition of silver reduced activity and number of denitrifiers, whereas their diversity increased. Because of this demonstrated sensitivity, it is proposed that denitrifiers are suitable indicator organisms for environmental pollution. In conclusion, this thesis shows that molecular methods show great potential for investigating diversity of denitrifiers in various environments, much of which is yet to be discovered. However, in order to fully understand the ecology of denitrifiers, methods targeting the active organisms must be developed, and more denitrifiers must be isolated and characterised

Smärtskattningsskalor till för tidigt födda barn - En systematisk litteraturstudie

Bakgrund: Obehandlad smärta hos för tidigt födda barn kan leda till både omedelbara och långtgående negativa effekter. För att kunna ge barnen en adekvat smärtbehandling är det viktigt att regelbunden smärtskatta dem, men då de inte kan kommunicera verbalt är de beroende av att andra kan tolka deras smärtsignaler. Syfte: Att identifiera smärtskattningsskalor riktade mot för tidigt födda barn samt undersöka deras validitet och reliabilitet. Metod: En systematisk litteraturstudie med arton inkluderade artiklar. Resultat: Fjorton smärtskattningsskalor anpassade till för tidigt födda barn identifierades. Alla visade god eller mycket god reliabilitet. Gällande validitet skiljde det sig åt mellan de olika instrumenten. Slutsats: Det går inte att rekommendera en specifik smärtskattningsskala baserat på denna litteraturstudie. Det är därför viktigt att fortsätta undersöka de mest lovande i större, kliniska studier och säkerställa deras validitet, reliabilitet, klinisk användbarhet och relevans

Opioid-inducerad obstipation i samband med postoperativ smärtbehandling : Förekomst och förebyggande åtgärder

Objective: The objective was to examine the incidence of constipation, and the preventive measures taken in relation with postoperative pain treatment with opioids at two orthopaedic surgery wards. Methods: The participants were patients that had undergone surgery in the back, hip or thigh. They were selected through systematic selection and a total of 46 electronic health records were examined. The factors investigated and tested for correlation with constipation were the usage of laxatives, daily fluid-intake and early mobilisation. Results: Totally, 26.1 % of the patients became constipated, and laxatives were prescribed to 65.2 % of the patients. Doctors prescribed 53.3 % of the laxatives, nurses 33.3 % and for the remaining 13.3 % it was uncertain who had written the prescription. Usage of laxatives seemed to cause constipation (p=0,025), whereas there was no correlation between constipation and early mobilization. The documentation regarding daily fluid-intake was insufficient and no correlation test could be performed. Conclusions: This study failed to demonstrate that usage of laxatives and early mobilization prevents constipation in patients postoperatively treated with opioids. There was a need for increased education about constipation and its preventing measures for health care workers

Opioid-inducerad obstipation i samband med postoperativ smärtbehandling : Förekomst och förebyggande åtgärder

Objective: The objective was to examine the incidence of constipation, and the preventive measures taken in relation with postoperative pain treatment with opioids at two orthopaedic surgery wards. Methods: The participants were patients that had undergone surgery in the back, hip or thigh. They were selected through systematic selection and a total of 46 electronic health records were examined. The factors investigated and tested for correlation with constipation were the usage of laxatives, daily fluid-intake and early mobilisation. Results: Totally, 26.1 % of the patients became constipated, and laxatives were prescribed to 65.2 % of the patients. Doctors prescribed 53.3 % of the laxatives, nurses 33.3 % and for the remaining 13.3 % it was uncertain who had written the prescription. Usage of laxatives seemed to cause constipation (p=0,025), whereas there was no correlation between constipation and early mobilization. The documentation regarding daily fluid-intake was insufficient and no correlation test could be performed. Conclusions: This study failed to demonstrate that usage of laxatives and early mobilization prevents constipation in patients postoperatively treated with opioids. There was a need for increased education about constipation and its preventing measures for health care workers

Opioid-inducerad obstipation i samband med postoperativ smärtbehandling : Förekomst och förebyggande åtgärder

Objective: The objective was to examine the incidence of constipation, and the preventive measures taken in relation with postoperative pain treatment with opioids at two orthopaedic surgery wards. Methods: The participants were patients that had undergone surgery in the back, hip or thigh. They were selected through systematic selection and a total of 46 electronic health records were examined. The factors investigated and tested for correlation with constipation were the usage of laxatives, daily fluid-intake and early mobilisation. Results: Totally, 26.1 % of the patients became constipated, and laxatives were prescribed to 65.2 % of the patients. Doctors prescribed 53.3 % of the laxatives, nurses 33.3 % and for the remaining 13.3 % it was uncertain who had written the prescription. Usage of laxatives seemed to cause constipation (p=0,025), whereas there was no correlation between constipation and early mobilization. The documentation regarding daily fluid-intake was insufficient and no correlation test could be performed. Conclusions: This study failed to demonstrate that usage of laxatives and early mobilization prevents constipation in patients postoperatively treated with opioids. There was a need for increased education about constipation and its preventing measures for health care workers

Metabolic Profiles and Genetic Diversity of Denitrifying Communities in Activated Sludge after Addition of Methanol or Ethanol

External carbon sources can enhance denitrification rates and thus improve nitrogen removal in wastewater treatment plants. The effects of adding methanol and ethanol on the genetic and metabolic diversity of denitrifying communities in activated sludge were compared using a pilot-scale plant with two parallel lines. A full-scale plant receiving the same municipal wastewater, but without external carbon source addition, was the reference. Metabolic profiles obtained from potential denitrification rates with 10 electron donors showed that the denitrifying communities altered their preferences for certain compounds after supplementation with methanol or ethanol and that methanol had the greater impact. Clone libraries of nirK and nirS genes, encoding the two different nitrite reductases in denitrifiers, revealed that methanol also increased the diversity of denitrifiers of the nirS type, which indicates that denitrifiers favored by methanol were on the rise in the community. This suggests that there might be a niche differentiation between nirS and nirK genotypes during activated sludge processes. The composition of nirS genotypes also varied greatly among all samples, whereas the nirK communities were more stable. The latter was confirmed by denaturing gradient gel electrophoresis of nirK communities on all sampling occasions. Our results support earlier hypotheses that the compositions of denitrifier communities change during predenitrification processes when external carbon sources are added, although no severe effect could be observed from an operational point of view