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Astals S, Peces M, Batstone DJ, Jensen PD, Tait S. Characterising and modelling free ammonia and ammonium inhibition in anaerobic systems. Water Res 2018; 143:127-135. [PMID: 29940358 DOI: 10.1016/j.watres.2018.06.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 06/04/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Inhibition by ammoniacal nitrogen, consisting of free ammonia (NH3) and ammonium ion (NH4+), has been widely investigated for anaerobic digestion. However, despite the large amount of research on the subject, ammoniacal nitrogen inhibition still threatens many anaerobic digesters. This paper presents (i) a method to reliably characterise ammoniacal nitrogen inhibition and (ii) a robust inhibition modelling approach. Results showed that NH3 and NH4+ inhibition need to be jointly determined, which can only be done by performing inhibition tests at various total ammoniacal nitrogen (TAN) concentrations and pH values. These test conditions were reliably achieved using the salts NH4HCO3 and NH4Cl without pH adjustment, rather than by using NH4Cl with pH adjustment. The use of only salts showed a lower pH change during the inhibition test (∼1.5 days), thereby decreasing the uncertainty in TAN speciation and strengthening the test and model outputs. A threshold inhibition function satisfactorily described (R2 > 0.99) the joint inhibition of NH3 and NH4+ on three distinct inocula, and provided a better description of the inhibition testing results than a non-competitive inhibition function (R2 ∼0.70). The key advantage of the proposed threshold inhibition function is its capacity to identify the inhibition lower limit (concentration where inhibition starts; KImin) and upper limit (concentration where inhibition is complete; KImax). The threshold inhibition function also identifies the 50% inhibition concentration (KI50) at the midpoint of KImin and KImax. Finally, experimental and model results show that at pH 7.3-7.7 and TAN concentrations above 2000 mgN·L-1, both NH3 and NH4+ contribute significantly to overall inhibition.
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Affiliation(s)
- S Astals
- Advanced Water Management Centre, The University of Queensland, Brisbane, 4072, QLD, Australia.
| | - M Peces
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, 4072, QLD, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, Brisbane, 4072, QLD, Australia
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2
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Yap SD, Astals S, Lu Y, Peces M, Jensen PD, Batstone DJ, Tait S. Humic acid inhibition of hydrolysis and methanogenesis with different anaerobic inocula. Waste Manag 2018; 80:130-136. [PMID: 30454992 DOI: 10.1016/j.wasman.2018.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 08/28/2018] [Accepted: 09/01/2018] [Indexed: 06/09/2023]
Abstract
There is increasing evidence that humic acid (HA) is hampering the performance of anaerobic digesters treating animal manures and thermally-hydrolysed waste activated sludge. In the present study, HA inhibition and inhibition resilience was examined for hydrolysis (carbohydrate and protein) and acetotrophic methanogenesis with four distinct full-scale anaerobic inocula. The aim was to further understand HA inhibition and to explore potential relationships between microbial factors and inhibition resilience. For two of the four tested inocula, cellulose degradation showed a start-up delay that lengthened as HA concentration increased from 0 to 2 g L-1. This inhibition was reversible because, after the initial delay, subsequent hydrolysis rates and methane yields were not significantly influenced by HA concentration. Cellulose hydrolysis results at HA concentrations below 2 g L-1 support a threshold inhibition mechanism, i.e. HA complexes with hydrolytic enzymes preventing them from binding with cellulose, but once all the HA had been complexed, enzymes subsequently released are free to bind with cellulose. Inocula with higher cellulose hydrolytic activity were less affected by HA inhibition, suggesting a potential link between HA inhibition resilience and microbial activity. However, above 5 gHA L-1, cellulose hydrolysis rates decreased with increasing HA concentration; indicating that the mechanisms of inhibition may change depending on some threshold HA concentration. Protein hydrolysis and acetotrophic methanogenesis were less susceptible to HA inhibition than cellulose hydrolysis, since signs of inhibition were only observed above 5 gHA L-1. Acetotrophic methanogenesis was partially inhibited at 10 gHA L-1 and completely inhibited at 20 gHA L-1. These results further support that HA inhibition is selective towards particular enzymes.
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Affiliation(s)
- S D Yap
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia.
| | - Y Lu
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore
| | - M Peces
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, 4072 Brisbane, QLD, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, 4072 Brisbane, QLD, Australia
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3
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Peces M, Astals S, Jensen PD, Clarke WP. Deterministic mechanisms define the long-term anaerobic digestion microbiome and its functionality regardless of the initial microbial community. Water Res 2018; 141:366-376. [PMID: 29807319 DOI: 10.1016/j.watres.2018.05.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/16/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The impact of the starting inoculum on long-term anaerobic digestion performance, process functionality and microbial community composition remains unclear. To understand the impact of starting inoculum, active microbial communities from four different full-scale anaerobic digesters were each used to inoculate four continuous lab-scale anaerobic digesters, which were operated identically for 295 days. Digesters were operated at 15 days solid retention time, an organic loading rate of 1 g COD Lr-1 d-1 (75:25 - cellulose:casein) and 37 °C. Results showed that long-term process performance, metabolic rates (hydrolytic, acetogenic, and methanogenic) and microbial community are independent of the inoculum source. Digesters process performance converged after 80 days, while metabolic rates and microbial communities converged after 120-145 days. The convergence of the different microbial communities towards a core-community proves that the deterministic factors (process operational conditions) were a stronger driver than the initial microbial community composition. Indeed, the core-community represented 72% of the relative abundance among the four digesters. Moreover, a number of positive correlations were observed between higher metabolic rates and the relative abundance of specific microbial groups. These correlations showed that both substrate consumers and suppliers trigger higher metabolic rates, expanding the knowledge of the nexus between microorganisms and functionality. Overall, these results support that deterministic factors control microbial communities in bioreactors independently of the inoculum source. Hence, it seems plausible that a desired microbial composition and functionality can be achieved by tuning process operational conditions.
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Affiliation(s)
- M Peces
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia.
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
| | - W P Clarke
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072, QLD, Australia
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Yap SD, Astals S, Jensen PD, Batstone DJ, Tait S. Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters. Waste Manag 2017; 64:79-87. [PMID: 28302526 DOI: 10.1016/j.wasman.2017.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 01/30/2017] [Accepted: 02/28/2017] [Indexed: 06/06/2023]
Abstract
Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH4 kgVSfed-1 for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community.
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Affiliation(s)
- S D Yap
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Yap SD, Astals S, Jensen PD, Batstone DJ, Tait S. Pilot-scale testing of a leachbed for anaerobic digestion of livestock residues on-farm. Waste Manag 2016; 50:300-308. [PMID: 26948667 DOI: 10.1016/j.wasman.2016.02.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/23/2016] [Accepted: 02/23/2016] [Indexed: 06/05/2023]
Abstract
A leachbed is a relatively simple anaerobic digester suitable for high-solids residues and on-farm applications. However, performance characteristics and optimal configuration of leachbeds are not well-understood. In this study, two 200 L pilot-scale leachbeds fed with spent straw bedding from pigs/swine (methane potential, B0 = 195-218 L CH4 kg(-1) VS fed) were used to assess the effects of leachate recirculation mode (trickling vs. flood-and-drain) on the digestion performance. Results showed comparable substrate solubilisation extents (30-45% of total chemical oxygen demand fed) and methane conversion (50% of the B0) for the trickling and flood-and-drain modes, indicating that digestion performance was insensitive to the mode of leachate flow. However, the flood-and-drain leachbed mobilised more particulates into the leachate than the trickling leachbed, an undesirable outcome, because these particulates were mostly non-biodegradable. Inoculation with solid residues from a previous leachbed (inoculum-to-substrate ratio of 0.22 on a VS basis) hastened the leachbed start-up, but methane recovery remained at 50% of the B0 regardless of the leachate recirculation mode. Post-digestion testing indicated that the leachbeds may have been limited by microbial activity/inhibition. The high residual methane potential of leachate from the trickling (residual Bo = 732 ± 7 L CH4 kg(-1) VS fed) and flood-and-drain leachbeds (582 ± 8 L CH4 kg(-1) VS fed) indicated an opportunity for further processing of leachate via a separate methanogenic step. Overall, a trickling leachbed appeared to be more favourable than the flood-and-drain leachbed for treating spent bedding at farm-scale due to easier operation.
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Affiliation(s)
- S D Yap
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
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Peces M, Astals S, Clarke WP, Jensen PD. Semi-aerobic fermentation as a novel pre-treatment to obtain VFA and increase methane yield from primary sludge. Bioresour Technol 2016; 200:631-638. [PMID: 26551651 DOI: 10.1016/j.biortech.2015.10.085] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 10/21/2015] [Accepted: 10/24/2015] [Indexed: 06/05/2023]
Abstract
There is a growing trend to consider organic wastes as potential sources of renewable energy and value-add products. Fermentation products have emerged as attractive value-add option due to relative easy production and broad application range. However, pre-fermentation and extraction of soluble products may impact down-stream treatment processes, particularly energy recovery by anaerobic digestion. This paper investigates primary sludge pre-fermentation at different temperatures (20, 37, 55, and 70°C), treatment times (12, 24, 48, and 72h), and oxygen availability (semi-aerobic, anaerobic); and its impact on anaerobic digestion. Pre-fermentation at 20 and 37°C succeeded for VFA production with acetate and propionate being major products. Pre-fermentation at 37, 55, and 70°C resulted in higher solubilisation yield but it reduced sludge methane potential by 20%. Under semi-aerobic conditions, pre-fermentation allowed both VFA recovery (43gCODVFAkg(-1)VS) and improved methane potential. The latter phenomenon was linked to fungi that colonised the sludge top layer during pre-fermentation.
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Affiliation(s)
- M Peces
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072 QLD, Australia
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072 QLD, Australia.
| | - W P Clarke
- Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia Campus, 4072 QLD, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St. Lucia Campus, 4072 QLD, Australia
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7
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Astals S, Batstone DJ, Tait S, Jensen PD. Development and validation of a rapid test for anaerobic inhibition and toxicity. Water Res 2015; 81:208-215. [PMID: 26065392 DOI: 10.1016/j.watres.2015.05.063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 05/26/2015] [Accepted: 05/31/2015] [Indexed: 06/04/2023]
Abstract
Despite the importance of quantifying inhibitory capacity of compounds in anaerobic digestion, there is currently no well-defined method to assess it. Experimental methods in literature are frequently time-consuming and resource intensive. As a result, detailed inhibition testing rarely forms part of anaerobic digestion studies, despite the importance and utility of this information. This study develops and validates a simple and rapid inhibition test protocol, based on relative inhibition of acetoclastic methanogens. The inhibition potential of a compound is determined from the reduction in specific methanogenic activity as inhibitor concentration is increased. The method was successfully performed on two inoculums from different source environments and with both biostatic and biocidal inhibitors. Optimisation work indicated that: (i) sodium acetate is a preferred carbon source compared to acetic acid; (ii) an inoculum to acetate ratio of 5 g VS g(-1) acetate is preferred, and (iii) that the inoculum concentration should be normalised to 10 g L(-1) VS to reduce mass transfer problems and promote consistency. A key advantage over existing methods is that the sampling strategy has been optimised to three events over 1.5 days while effectively controlling the relative analytical error.
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Affiliation(s)
- S Astals
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
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8
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Astals S, Musenze RS, Bai X, Tannock S, Tait S, Pratt S, Jensen PD. Anaerobic co-digestion of pig manure and algae: impact of intracellular algal products recovery on co-digestion performance. Bioresour Technol 2015; 181:97-104. [PMID: 25643955 DOI: 10.1016/j.biortech.2015.01.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/07/2015] [Accepted: 01/09/2015] [Indexed: 05/08/2023]
Abstract
This paper investigates anaerobic co-digestion of pig manure and algae (Scenedesmus sp.) with and without extraction of intracellular algal co-products, with views towards the development of a biorefinery concept for lipid, protein and/or biogas production. Protein and/or lipids were extracted from Scenedesmus sp. using free nitrous acid pre-treatments and solvent-based Soxhlet extraction, respectively. Processing increased algae methane yield between 29% and 37% compared to raw algae (VS basis), but reduced the amount of algae available for digestion. Co-digestion experiments showed a synergy between pig manure and raw algae that increased raw algae methane yield from 0.163 to 0.245 m(3) CH4 kg(-1)VS. No such synergy was observed when algal residues were co-digested with pig manure. Finally, experimental results were used to develop a high-level concept for an integrated biorefinery processing pig manure and onsite cultivated algae, evaluating methane production and co-product recovery per mass of pig manure entering the refinery.
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Affiliation(s)
- S Astals
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - R S Musenze
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - X Bai
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - S Tannock
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia; School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - S Tait
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia
| | - S Pratt
- School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, Brisbane, QLD 4072, Australia.
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Liaquat R, Astals S, Jensen PD, Batstone DJ, Tait S. Inhibition resilience of microbes in pig effluent lagoons. Anim Prod Sci 2015. [DOI: 10.1071/anv55n12ab053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Jensen PD, Astals S, Lu Y, Devadas M, Batstone DJ. Anaerobic codigestion of sewage sludge and glycerol, focusing on process kinetics, microbial dynamics and sludge dewaterability. Water Res 2014; 67:355-366. [PMID: 25459224 DOI: 10.1016/j.watres.2014.09.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 08/30/2014] [Accepted: 09/19/2014] [Indexed: 06/04/2023]
Abstract
Anaerobic codigestion (AcoD) is a proven option to significantly boost biogas production while utilizing existing digesters and infrastructure. The aim of the present research was to conduct an exhaustive study regarding anaerobic codigestion of mixed sewage sludge and crude glycerol considering impacts on organic load, hydraulic load, process performance and microbial community. The methane potential of crude glycerol varied from 370 mL CH4·g(-1) VS to 483 mL CH4·g(-1) VS for different samples tested. The half maximal inhibitory concentration of crude glycerol was 1.01 g VS L(-1), and the primary mechanism of inhibition was through overload from rapid fermentation rather than the presence of toxic compounds in the crude glycerol. In continuous operation over 200 days, feeding glycerol at up to 2% v/v, increased organic load by up to 70% and resulted in a 50% increase in methane production. Glycerol dosing resulted in no change in apparent dewaterability, with both codigestion and control reactors returning values of 22%-24%. Members of the phylum Thermotogae emerged as a niche population during AcoD of sewage sludge and glycerol; however there was no gross change in microbial community structure and only minimal changes in diversity. AcoD did not result in synergisms between sewage sludge and crude glycerol. Actually, at dose rate up to 2% v/v glycerol dosing is still an effective strategy to increase the organic loading rate of continuous anaerobic digesters with minimal impact of the hydraulic retention time. Nonetheless, the dose rate must be managed to: (i) prevent process inhibition and (ii) ensure sufficient degradation time to produce a stable biosolids product.
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Affiliation(s)
- P D Jensen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - S Astals
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia; Department of Chemical Engineering, University of Barcelona, C/ Martí i Franquès, No. 1, 6th Floor, 08028 Barcelona, Spain.
| | - Y Lu
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
| | - M Devadas
- Integrated Planning, Melbourne Water, 990 Latrobe Street, Docklands, Victoria 3001, Australia.
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Astals S, Batstone DJ, Mata-Alvarez J, Jensen PD. Identification of synergistic impacts during anaerobic co-digestion of organic wastes. Bioresour Technol 2014; 169:421-427. [PMID: 25079207 DOI: 10.1016/j.biortech.2014.07.024] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 06/30/2014] [Accepted: 07/04/2014] [Indexed: 05/26/2023]
Abstract
Anaerobic co-digestion has been widely investigated, but there is limited analysis of interaction between substrates. The objective of this work was to assess the role of carbohydrates, protein and lipids in co-digestion behaviour separately, and together. Two sets of batch tests were done, each set consisting of the mono-digestion of three substrates, and the co-digestion of seven mixtures. The first was done with pure substrates--cellulose, casein and olive oil--while in the second slaughterhouse waste--paunch, blood and fat--were used as carbohydrate, protein and lipid sources, respectively. Synergistic effects were mainly improvement of process kinetics without a significant change in biodegradability. Kinetics improvement was linked to the mitigation of inhibitory compounds, particularly fats dilution. The exception was co-digestion of paunch with lipids, which resulted in an improved final yield with model based analysis indicating the presence of paunch improved degradability of the fatty feed.
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Affiliation(s)
- S Astals
- Department of Chemical Engineering, University of Barcelona, C/ Martí i Franquès, No. 1, 6th Floor, 08028 Barcelona, Spain; Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - D J Batstone
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - J Mata-Alvarez
- Department of Chemical Engineering, University of Barcelona, C/ Martí i Franquès, No. 1, 6th Floor, 08028 Barcelona, Spain
| | - P D Jensen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Batstone DJ, Pavlostathis SG, Jensen PD, Angelidaki I. Comment on "Parameter identification and modeling of the biochemical methane potential of waste activated sludge". Environ Sci Technol 2011; 45:7596-7599. [PMID: 21809862 DOI: 10.1021/es201803j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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13
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Abstract
With several advantages over the conventional mesophilic anaerobic digestion, such as better sludge quality and higher biogas production, thermophilic anaerobic digestion is regarded as a promising alternative for sludge digestion. Primary and activated sludges are complex materials, and historically, analysis of kinetics has been largely on whole sludge, without analysis of individual components. This paper analyses relative digestion kinetics of pure substrates designed to target main stages of sludge digestion under thermophilic and mesophilic conditions. Hydrolysis rate of cellulose was significantly influenced by temperature with hydrolysis coefficients of--at 55 degrees C (0.7 +/- 0.1 day(-1)), 60 degrees C (0.8 +/- 0.2 day(-1)), 65 degrees C (1.1 +/- 0.2 day(-1)) and 70 degrees C (1.2 +/- 0.2 day(-1)) over 38 degrees C (0.4 +/- 0.1 day(-1)). This strongly follows the Arrhenius relationship, with an activation energy (E(A)) of 31 +/- 4 kJ mol(-1), corresponding to an increase of 1.5x for each 10 degrees C of temperature increase. Glucose uptake was rapid with a wide variety of fermentation products detected under mesophilic conditions, while uptake was slower under thermophilic conditions with acetate and propionate being dominant products. Propionate acetogenesis and acetate-utilizing methanogenesis kinetics were not influenced by temperatures. Hydrolysis is widely regarded as a rate-limiting step in sludge digestion, thus improvements in hydrolysis rates as measured during this study have the potential for significant improvements in overall apparent sludge digestion rates.
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Affiliation(s)
- H Ge
- AWMC, Advanced Water Management Centre, Environmental Biotechnology CRC, The University of Queensland, St Lucia, QLD 4072, Australia
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Jensen PD, Ge H, Batstone DJ. Assessing the role of biochemical methane potential tests in determining anaerobic degradability rate and extent. Water Sci Technol 2011; 64:880-886. [PMID: 22097074 DOI: 10.2166/wst.2011.662] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The biodegradability and bioavailability of hydrolysis-limited substrates under anaerobic (and aerobic) conditions can be represented by two key parameters--degradability (f(d)), or the percentage that can be effectively be destroyed during digestion, and first order hydrolysis coefficient (k(hyd)), or the speed at which material breaks down. Biochemical methane potential (BMP) testing uses a batch test (in triplicate), and by fitting against a first order model, can fit both parameters in the same test. BMP testing is now being widely used for anaerobic process feasibility and design purposes, and standardisation efforts are ongoing. In this paper, we address a number of key issues relating to the test method and its analysis. This includes proposal of a new fitting and parameter estimation method, evaluation of the impact of inoculum to substrate ratio on fitted parameters, and comparison to performance in continuous systems. The new parameter estimation technique provides an estimate of parameter uncertainty and correlation, and is clearly more suitable than model transformation and linear regression. An inoculum volume ratio of at least 50% (2:1 on VS basis) was required on a cellulose substrate to use methane production as primary indicator, as found by comparing methane production and solubilisation of cellulose. Finally, on a typical material, waste activated sludge, the batch test was slightly conservative in terms of degradability and rate, indicating a bias in the BMP test. The test is a cost-effective and capable method to evaluate potential substrates, but it should be noted that it is generally conservative, especially if sub-optimal inoculum is used.
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Affiliation(s)
- P D Jensen
- Advanced Water Management Centre, The University of Queensland, St Lucia, QLD 4072, Australia.
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Jensen PD, Hardin MT, Clarke WP. Measurement and quantification of sessile and planktonic microbial populations during the anaerobic digestion of cellulose. Water Sci Technol 2008; 57:465-469. [PMID: 18359982 DOI: 10.2166/wst.2008.106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Crystalline cellulose was anaerobically degraded using a leachate inoculum derived from simulated municipal solid waste. Bicinchoninic Acid (BCA) protein assays were used to measure the distribution of biomass during cellulose degradation, including the planktonic and sessile biomass fractions. A comparison of sessile and planktonic microbial growth indicated that the microbial growth was dominated by the planktonic fraction with the biofilms accounting for approximately 25% of the population. Additional biomass measurements were conducted to test the reliability of the BCA protein assays. Total microbial growth was inferred from the accumulation and depletion of ammonia nitrogen measured using flow injection analysis. The planktonic biomass was estimated from direct cell counts using light microscopy and the sessile biomass was estimated by analysing the nitrogen content of the separated and washed cellulose pellet. Regression analysis showed good correlations between the measurement pairs representing the total biomass (R2=0.90), planktonic biomass (R2=0.97) and sessile biomass (R2=0.85), supporting the use of protein assays as an indicator of microbial growth in mixed culture environments.
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Affiliation(s)
- P D Jensen
- School of Engineering, University of Queensland, Brisbane, 4072, Australia.
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16
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Clarke WP, Radnidge P, Lai TE, Jensen PD, Hardin MT. Digestion of waste bananas to generate energy in Australia. Waste Manag 2008; 28:527-33. [PMID: 17376668 DOI: 10.1016/j.wasman.2007.01.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 11/14/2006] [Accepted: 01/24/2007] [Indexed: 05/14/2023]
Abstract
This paper presents results from laboratory studies to measure the methane yield and rate of digestion of reject bananas. These parameters were determined in experiments that took into account the likely configuration of a full-scale plant in the banana growing region of north Queensland. The digestion was conducted in a 200-l reactor using fed-batch operation, relying entirely on the natural microbial consortia on the reject bananas to avoid reliance on external inocula such as sludge, an undesirable material around food packaging facilities. An enrichment culture was first established in a highly buffered 200-l batch digestion unit. The fed-batch digester was then started by exchanging leachate with the mature batch reactor. Under loading conditions of 0.6 kg VS m(-3)d(-1) over 70 days where the average working volume was 160 l, the digester produced 398+/-20 l CH4 kg VS(-1). Increasing the loading rate to 1.6 kg VS m(-3)d(-1) resulted in a reduced methane yield of 210 l CH4 kg VS(-1) over 23 days of operation, with a concomitant accumulation of banana waste in the digester. The leachate at the end of digestion contained over 4000 mg l(-1)K, 200 mg l(-1) N and 75 mg l(-1), levels that exceed acceptable limits for general agricultural irrigation.
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Affiliation(s)
- W P Clarke
- School of Engineering, The University of Queensland, Brisbane 4072, Australia.
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17
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Jensen PD, Johnson LR, Trumble JT. Individual and joint actions of selenate and methylmercury on the development and survival of insect detritivore Megaselia scalaris (Diptera: Phoridae). Arch Environ Contam Toxicol 2006; 50:523-30. [PMID: 16418899 DOI: 10.1007/s00244-005-0111-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2005] [Accepted: 08/22/2005] [Indexed: 05/06/2023]
Abstract
Despite the important roles played by insects in most ecosystems, surprisingly little is known about how anthropogenic pollutants or their mixtures interact to affect insect populations. The independent and joint actions of selenate and methylmercury on a ubiquitous insect detritivore, Megaselia scalaris (Loew), were determined in this study. Ovipositing females did not distinguish between untreated food sources and those contaminated with toxic concentrations of selenate, methylmercury, or both chemicals in combination. Even at the highest concentrations of pollutants, no negative effects were observed for the egg stage. However, larval survival was significantly decreased and development significantly prolonged by selenate and methylmercury individually at low or intermediate ecologically relevant treatment levels. Potentiation was strongly evident because mixtures containing concentrations as little as only 1% of the respective individual median lethal tolerances (LC(50)s) caused significantly more mortality and delayed larval development than would be expected from the responses selenate and methylmercury elicit individually. However, survival and pupal development was not affected at any rate tested. Female fecundity was significantly decreased by methylmercury but not by selenate or mixture treatments. The relative toxicity to M. scalaris of each of the individual and joint treatments was selenate (LC(50) = 260 microg/g) < methylmercury (LC(50) = 22 microg/g) < the mixture at approximately 5% of the LC(50) concentration of each of the components (12 microg/g selenate plus 1.0 microg/g methylmercury). The increased mortality and delayed larval development within sites contaminated by selenate, methylmercury, or combination of the two have substantial implications for the ecology, population dynamics, and sustainability of M. scalaris populations. If these results can be extrapolated to other arthropod detritivores, ecosystem food-web function may be substantially affected.
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Affiliation(s)
- P D Jensen
- Department of Entomology, University of California, Riverside, 92521, USA.
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18
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Jensen PD, Jensen FT, Christensen T, Heickendorff L, Jensen LG, Ellegaard J. Indirect evidence for the potential ability of magnetic resonance imaging to evaluate the myocardial iron content in patients with transfusional iron overload. MAGMA 2001; 12:153-66. [PMID: 11390271 DOI: 10.1007/bf02668097] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to evaluate the potential ability of magnetic resonance imaging (MRI) for evaluation of myocardial iron deposits. The applied MRI technique has earlier been validated for quantitative determination of the liver iron concentration. The method involves cardiac gating and may, therefore, also be used for simultaneous evaluation of myocardial iron. The tissue signal intensities were measured from spin echo images and the myocardium/muscle signal intensity ratio was determined. The SI ratio was converted to tissue iron concentration values based on a modified calibration curve from the liver model. The crucial steps of the method were optimized; i.e. recognition and selection of the myocardial slice for analysis and positioning of the regions of interest (ROIs) within the myocardium and the skeletal muscle. This made the myocardial MRI measurements sufficiently reproducible. We applied this method in 41 multiply transfused patients. Our data demonstrate significant positive linear relationships between different iron store parameters and the MRI-derived myocardial iron concentration, which was significantly related to the serum ferritin concentration (rho=0.62, P<0.0001) and to the MRI-determined liver iron concentration (rho=0.36, P=0.02). The myocardial MRI iron concentrations demonstrated also a significant positive correlation with the number of blood units given (rho=0.45, P=0.005) and the aminotransferase serum concentration (rho=0.54, P=0.0008). Our data represents indirect evidence for the ability of MRI techniques based on myocardium/muscle signal intensity ratio measurements to evaluate myocardial iron overload.
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Affiliation(s)
- P D Jensen
- Department of Hematology, Amtssygehuset, Aarhus University Hospital, Tage Hansensgade 2, DK-8000 Aarhus C, Denmark
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Jensen PD, Heickendorff L, Carlson I, Jensen FT, Christensen T, Ellegaard J. Expression of CD2 and activation markers on blood T-helper cell subsets in patients with transfusional iron overload. Transfus Med 2001; 11:21-30. [PMID: 11328568 DOI: 10.1046/j.1365-3148.2001.00283.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The aim of the present study was to investigate the relationship between different measures of iron status, and the expression of CD2, and the activation markers CD25, CD71, CD45RO, HLADR CD38 within the Th-cell subset in patients with progressive transfusional iron overload. We estimated the expression of the activation surface markers on the Th cells of peripheral blood by flow cytometry from 22 multiply transfused patients. The number of CD2 binding sites (BS) on Th cells was significantly higher in the patients (82 917 +/- 30 801) than in age-matched normal controls (41 145 +/- 6989, P < 0.0001). When investigating whether this difference could be due to the iron overload we found the number of CD2 BS closely related to the iron saturation of serum transferrin (TfS) (R2 = 0.78, P < 0.001). The relationship to the serum ferritin concentration and to the number of blood units given was weaker, but also significant (R2 = 0.22, P < 0.027, respectively, R2 = 0.21, P < 0.032). Also the fraction of mature memory Th cells which express CD45RO at a high level was directly related to the TfS (R2 = 0.57, P < 0.0001), while the expression of CD38 within the Th cell fraction was inversely related to the TfS (R2 = - 0.43, P = 0.009). The expression of HLA-DR (but not of CD25 and CD71) was also directly related to the TfS (R2 = 0.29, P = 0.01). Our results show a clear, statistical relationship between the iron status and the expression of surface markers within Th cells in multiply transfused patients.
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Affiliation(s)
- P D Jensen
- Department of Haematology, Aarhus Amtssygehus, Aarhus University Hospital, Denmark
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Nørgaard JM, Jensen PD, Bendix K, Clausen N, Palshof T. Relevance of in vitro leukaemia cell survival to short- and long term clinical outcome in AML. Leuk Lymphoma 1999; 32:327-37. [PMID: 10037030 DOI: 10.3109/10428199909167393] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In ninety-three cases of newly diagnosed acute myeloid leukaemia (AML) we investigated the importance to short- and long term clinical outcome of the in vitro short term leukaemia cell survival as measured by a 4-day MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide)-assay. In 67 patients treated by intravenous remission induction therapy we found that patients who after the first induction cycle or after induction therapy overall achieved a complete remission (CR) had leukaemia cells with significantly lower in vitro cell survival ability than cells of non-responders (p = 0.02 and 0.06, respectively). These relations remained statistically significant in subsequent multivariate analyses. Likewise, a favourable effect of low in vitro leukaemia cell survival on overall survival of the patients was detected in the (largest) subgroup of adult patients treated uniformly by the same remission induction regimen as well as in all patients. However, in the 44 patients, who achieved CR, the in vitro leukaemia cell survival did not show significance to remission duration or time to first relapse. Furthermore, the leukaemia cell survival (MTT-assay) did not to correlate with the Bcl-2 expression level (quantitative flow cytometry) of the leukaemia cells (r = 0.18, n = 34, p = 0.32). In addition, in a cell line model employing the growth factor dependent MO7 human AML cell line, growth factor withdrawal was associated with rapid onset of cellular apoptosis as evaluated by morphology, occurrence of a subG1 peak in DNA histograms, and loss of cellular activity in the MTT-assay. In contrast, a more moderate decline in Bcl-2 expression and gradual loss of ability to exclude the trypan blue dye was seen in the leukaemia cells in response to growth factor withdrawal. We conclude, that the MTT-assay provides a simple and sensitive method for measuring in vitro cell survival. The differences in leukaemia cell survival seen in AML may well be clinically relevant and may help to provide a better understanding of clinical drug resistance.
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Affiliation(s)
- J M Nørgaard
- Department of Medicine and Hematology, Aarhus University Hospital, Denmark
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Jensen PD, Jensen FT, Christensen T, Ellegard J. [Quantification of iron level in the liver by MR imaging in patients treated for transfusion siderosis]. Ugeskr Laeger 1998; 160:1168-74. [PMID: 9492628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Patients with chronic blood transfusion requirements develop progressive iron overload, which is followed by organ damage in severe cases. Chemical determination of the liver iron concentration in liver biopsies is still regarded as the gold-standard for a precise determination of the degree of iron overload, but cannot be performed just for determination of the liver iron concentration alone due to the possible harmful side effects due to percutaneous liver biopsies. We have therefore validated a non-invasive MRI-technique based on the calculation of the ratio between the signal intensity (SIR) of the liver and skeletal muscle. We found a good correlation between the chemically determined liver iron concentration and the corresponding SIR-values (r2 = 0.98, p < 0.0001) low inter-day variation (2.9 +/- 2.7 mumol Fe/g) indicating that our non-invasive method is applicable for the determination of the liver iron concentration and may also be used for monitoring the efficacy of iron chelation by repeated measurements.
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Affiliation(s)
- P D Jensen
- Arhus Universitethospital, Arhus Amtssygus, medicinsk-haematologisk afdeling
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Jensen PD, Olsen N, Bagger JP, Jensen FT, Christensen T, Ellegaard J. Cardiac function during iron chelation therapy in adult non-thalassaemic patients with transfusional iron overload. Eur J Haematol 1997; 59:221-30. [PMID: 9338620 DOI: 10.1111/j.1600-0609.1997.tb00981.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
It is well-documented that iron chelation by desferrioxamine protects/improves the cardiac function in blood transfusion-dependent children suffering from beta-thalassaemia. In patients who do not become dependent upon blood transfusion until adulthood (ANT-patients), iron chelation by desferrioxamine may affect the cardiac function in unknown ways, presumably because age-related changes in the heart may cause iron chelation to affect the cardiac function in different ways. We therefore followed the left ventricular ejection fraction (LVEF) by multigated radionuclide angiography in 16 iron-loaded ANT-patients during iron chelation alone and after increasing the efficacy of chelation by vitamin C supplementation. During 12 months of iron chelation the mean LVEF fell significantly from 63.3% to 58.0% (p=0.04). Individual changes in LVEF did not correlate significantly with age but with the pretreatment liver iron concentration. After initiation of vitamin C supplementation, the mean LVEF increased from 55.9% to 65.3% (p=0.01). Our data suggest that in ANT-patients prolonged desferrioxamine treatment without vitamin C supplementation may be associated with reduced LVEF, whereas vitamin C supplementation seems to benefit the cardiac function. Similar findings have not been described in beta-thalassaemia and may hence be specific for ANT-patients. However, our findings have to be confirmed by controlled studies.
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Affiliation(s)
- P D Jensen
- Department of Medicine, Aarhus Amtssygehus, Denmark
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Jensen PD, Heickendorff L, Pedersen B, Bendix-Hansen K, Jensen FT, Christensen T, Boesen AM, Ellegaard J, Guerci AP. Le traitement (ff) par desferrioxamine (Desféral®) peut améliorer l'état hématologique des patients avec un syndrome myélodysplasique. Rev Med Interne 1996. [DOI: 10.1016/s0248-8663(97)80859-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Jensen PD, Heickendorff L, Pedersen B, Bendix-Hansen K, Jensen FT, Christensen T, Boesen AM, Ellegaard J. The effect of iron chelation on haemopoiesis in MDS patients with transfusional iron overload. Br J Haematol 1996; 94:288-99. [PMID: 8759889 DOI: 10.1046/j.1365-2141.1996.d01-1795.x] [Citation(s) in RCA: 159] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Long-term follow-up data are presented on changes in peripheral blood counts and Hb requirements of 11 patients with myelodysplastic syndromes (MDS) during iron chelation treatment with desferrioxamine for up to 60 months. The erythroid marrow activity was indirectly evaluated by repeated determinations of the serum transferrin receptor concentration. The efficacy of iron chelation was evaluated by repeated quantitative determination of the liver iron concentration by magnetic resonance imaging. Reduction in the Hb requirement ( > or = 50%) was seen in 7/11 (64%) patients. Five patients (46%) became blood transfusion independent. Platelet counts increased in 7/11 (64%) patients and the neutrophil counts in 7/9 (78%) evaluable patients. All patients in whom iron chelation was highly effective showed improvement of erythropoietic output accompanied by an increase in the serum transferrin receptor concentration. It is concluded that reduction in cytopenia in MDS patients may be accomplished by treatment with desferrioxamine, if the iron chelation is efficient and the patients are treated for a sufficiently long period of time. Exactly how treatment with desferrioxamine works remains a challenge for further investigation.
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Affiliation(s)
- P D Jensen
- Department of Medicine and Haematology, Aarhus University Hospital, Denmark
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25
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Abstract
Patients with severe iron overload may develop hepatic fibrosis due to iron toxicity. Unfortunately, the follow-up of the fibrogenic activity during treatment by histological examination of tissue biopsies carries potential side effects, and may therefore not be justified ethically. Recently, the serum concentration of procollagen type III peptide (S-PIIINP) has been shown to be a valid serum marker of the activity of collagen metabolism in conditions with hepatic fibrosis unrelated to iron overload. In order to evaluate the potential usefulness of this test in patients with fibrosis due to iron overload, we investigated the relationship between the PIIINP serum concentration and the size of iron overload in 18 patients with hereditary haemochromatosis (HH) and in 14 patients with transfusional iron overload. A close correlation was found between S-ferritin and S-PIIINP (r = 0.73, p < 0.0001). Follow-up of 6 patients during iron depletion treatment revealed a normalization of the serum aminotransferase concentration before normalization of S-PIIINP was found. This may indicate that excess iron directly induces an increase in fibrogenesis rather than the increased fibrogenesis is secondary to hepatocellular injury caused by iron excess. Thus, serial measurements S-PIIINP may be useful in follow-up of the fibrogenic process due to iron overload.
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Affiliation(s)
- P D Jensen
- Department of Medicine, Aarbus University Hospital, Denmark
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26
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Jensen IM, Jensen PD, Hokland ME, Hokland P, Ellegaard J. [Erythropoiesis in myelodysplastic syndrome detected by multiparameter flow cytometry]. Ugeskr Laeger 1995; 157:5092-6. [PMID: 7502376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
By staining human bone marrow cells with a monoclonal antibody reacting with surface antigens on erythroid precursor cells (AS-E1) and with propidium iodide reacting with nuclear DNA, we have evaluated the proliferative activity of erythropoiesis in patients with myelodysplastic syndromes using flow cytometric analysis. Comparing 36 patients (13 RA/RAS, 13 RAEB, 10 RAEB-t) with seven normal controls, significant differences in both the percentage of erythroid precursor cells and the fraction of these cells in the S or S-G2M-phase of the DNA cell cycle between the four groups were found. Since neither the percentage of erythroid precursor cells nor their fraction in S or S-G2M phase alone was found to characterize their proliferative activity, we calculated the proliferative fractions of the erythroid cells, i.e. the number of the erythroid precursor cells in S or S-G2M related to all bone marrow cells in S or S-G2M phase. Applying these parameters, we found significantly increased proliferative fractions of erythroid precursor cells in the RA/RAS patients compared to the normal controls (p-0.03 and 0.002 respectively), as well as a highly significant decrease with disease progression.
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Affiliation(s)
- I M Jensen
- Medicinsk-haematologisk afdeling, Arhus Amtssygehus
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27
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Jensen PD, Jensen FT, Christensen T, Ellegaard J. Evaluation of transfusional iron overload before and during iron chelation by magnetic resonance imaging of the liver and determination of serum ferritin in adult non-thalassaemic patients. Br J Haematol 1995; 89:880-9. [PMID: 7772526 DOI: 10.1111/j.1365-2141.1995.tb08428.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The ability to quantitate transfusional iron overload is crucial for determining the need for and the efficacy of chelation therapy in patients with long-standing transfusion-dependent anaemias. We evaluated the usefulness of some indirect measures of iron overload in estimating the iron concentration in the liver--the most important iron storage organ--in 26 non-chelated adult non-thalassaemic patients. Liver iron concentration was determined non-invasively by magnetic resonance imaging (MRI). The standard error of the estimated liver iron concentration was 80 mumol Fe/g dried liver tissue when using the number of transfused blood units, and 93 mumol Fe/g when using a serum ferritin assay. Follow-up in 11 patients (12-48 months) revealed that serum ferritin is a poor measure of the liver iron concentration during iron chelation. However, this discrepancy was individually different and seemed to be dependent on the erythropoietic marrow activity. By monitoring the liver iron concentration by MRI, we compared the efficacy of chelation with desferrioxamine given either by subcutaneous continuous infusions or by bolus injections. Depletion of liver iron stores could be achieved efficiently by both regimens.
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Affiliation(s)
- P D Jensen
- Department of Medicine and Haematology, Amtssygehuset, Aarhus University Hospital, Denmark
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Hindkjaer J, Hammoudah SA, Hansen KB, Jensen PD, Koch J, Pedersen B. Translocation (1;16) identified by chromosome painting, and PRimed IN Situ-labeling (PRINS). Report of two cases and review of the cytogenetic literature. Cancer Genet Cytogenet 1995; 79:15-20. [PMID: 7850745 DOI: 10.1016/0165-4608(94)00102-h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We used the molecular cytogenetic in situ techniques chromosome painting and PRimed IN Situ labeling (PRINS) to elaborate the cytogenetic observations in two cases of the rare aberration der(16)t(1;16), which occurs in a wide variation of hematologic and nonhematologic malignancies [1-3]. Review of the literature showed that, in contrast to the chromosome 1 breakpoint, the breakpoint on chromosome 16 is associated with diagnosis as well as patient age.
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Affiliation(s)
- J Hindkjaer
- Department of Cytogenetics, Danish Cancer Society, Aarhus
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Jensen PD, Lunding K. The pension fund for nurses in Denmark. Int Nurs Rev 1994; 41:173-6. [PMID: 7868313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
As women and because of their job mobility and low wages, female nurses in many countries are among the employee groups most severely disadvantaged under pension schemes. For many national nurses' associations, an adequate and equitable pension income for nurses after retirement is a major concern. Below a report on the system the Danish Nurses' Organization secured for nurses in Denmark--a system that offers nurses the best possible pension conditions and support when ill and disabled--and on page 177 a summary of efforts by the American Nurses' Association to make a portable pension system for nurses a legal requirement for employers.
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Jensen PD, Peterslund NA, Poulsen JH, Jensen FT, Christensen T, Ellegaard J. The effect of iron overload and iron reductive treatment on the serum concentration of carbohydrate-deficient transferrin. Br J Haematol 1994; 88:56-63. [PMID: 7803257 DOI: 10.1111/j.1365-2141.1994.tb04977.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The concentration of carbohydrate-deficient transferrin in serum (CDT) has been used as a reliable indicator of recent alcohol consumption. We have investigated the utility of this laboratory test in 20 patients with hereditary haemochromatosis (HH) by simultaneous evaluation of serum concentrations of liver transaminases, gamma-glutamyl transpeptidase, iron, transferrin and assessment of the liver iron concentration by magnetic resonance imaging. 11 patients were re-examined during iron depletion with phlebotomies. In all 11 patients intensive but not maintenance iron removal was associated with an increase in serum CDT, in three patients even to levels above the reference range. The mean serum CDT increased from 8.5 (SD 2.2) U/l to 16.6 (SD 7.2) U/l (P < 0.001). Iron mobilization from the liver was found particularly responsible for the increase in serum CDT. Independent of this finding we found a significant semi-logarithmic correlation (r = -0.77, P = 0.009) between the MRI determined liver iron concentration and serum CDT in the patients not on iron depletion. Our findings indicate that the utility of serum CDT as a measure of alcohol consumption in patients with HH may be compromised, especially during intensive iron depletion.
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Affiliation(s)
- P D Jensen
- Department of Medicine and Haematology, Psychiatric Hospital, Risskov, Denmark
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Abstract
OBJECTIVE To determine population pharmacokinetic parameters of vancomycin in neonates. METHODS This was a retrospective design, with prospective validation. Two hundred ten sequential neonates were evaluated at the neonatal intensive care units of Minneapolis Children's Medical Center and Children's Hospital of St. Paul. Five hundred twenty serum concentrations from 192 patients were included. A mean +/- SD gestational age of 29.5 +/- 5.1 weeks, postnatal age of 16.5 +/- 19.6 days, and dosing weight of 1492 +/- 1053 gm described the population. Thirty additional patients were studied for validation. Dosing, serum concentrations, and 28 covariates were collected. Data were evaluated with NONMEM. Forward selection and backward elimination regression identified significant covariates. One- and two-compartment population pharmacokinetic parameters and predictive performance of the models were measured. RESULTS Two-compartment final regression equations were as follows: Clearance (CL) = 0.0590 L/kg/hr (multiplied by 0.460 if exposed to dopamine and 0.643 if gestational age was < or = 32 weeks), central volume (VC) = 0.440 L/kg, intercompartmental clearance (Q) = 0.0313 L/hr/kg, and steady-state volume of distribution (Vss) = 0.764 L/kg. Interindividual variability was 40.6% for CL, 54.1% for Vss, and 16.8% for VC. Residual variability was 3.3 micrograms/ml. One-compartment final regression equations were: CL = 0.0626 L/kg/hr (multiplied by 0.455 if exposed to dopamine and 0.656 if gestational age was < or = 32 weeks), and Vd = 0.496 L/kg. Differences in relative performance were insignificant by use of one- or two-compartment parameters. CONCLUSIONS Gestational age < or = 32 weeks and concurrent use of dopamine were significant factors in prediction of vancomycin clearance. alpha Half-lives of 2.8 to 3.7 hours and beta half-lives of 13.4 to 33.7 hours suggest that some individuals in this neonatal population have considerably longer half-lives than those previously reported.
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Affiliation(s)
- R E Seay
- Minneapolis Children's Medical Center, Clinical Pharmacy Department, MN 55404
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32
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Abstract
We investigated the clinical usefulness of a standard magnetic resonance imaging (MRI) system for non-invasive determination of the liver iron concentration in 38 patients with iron overload and 15 normal controls by measurement of the signal intensity ratio between liver and skeletal muscle (SIR). However, SIR was found dependent on the applied repetition time (TR) of the MRI system, which led us to investigate this relationship in autopsy material of liver and muscle tissue specimens with various iron content. Based on these results, adjustment of SIR measurements to a constant value of TR was achieved. By use of this technique we found a close correlation between MRI and chemically determined liver iron concentration (r2 = 0.98) as well as the serum ferritin concentration (r2 = 0.86). The reproducibility was sufficiently good for the use of MRI in the follow-up of iron reductive treatment. The use of iron store parameters in serum was found insufficient as indicators of endpoint for venesection therapy, if 20 mumol Fe/g dry weight was applied as the upper reference limit of the liver iron concentration. It is concluded that MRI based on SIR measurements offers a precise and reproducible non-invasive method for the determination and follow-up of iron overload within a wide range of liver iron concentrations. Our findings may increase the clinical use of MRI in haematological patients with iron overload.
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Affiliation(s)
- P D Jensen
- Department of Medicine and Haematology, Amtssygehuset, Denmark
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33
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Stallknecht K, Jensen PD. [Overcrowding in hospitals. Statement on overcrowding and consequences for patients and staff]. Sygeplejersken 1994; 94:3-15. [PMID: 7940310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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34
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Jensen PD, Bagger JP, Jensen FT, Baandrup U, Christensen T, Ellegaard J. Heart transplantation in a case of juvenile hereditary haemochromatosis followed up by MRI and endomyocardial biopsies. Eur J Haematol 1993; 51:199-205. [PMID: 8243607 DOI: 10.1111/j.1600-0609.1993.tb00630.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cardiac involvement in hereditary haemochromatosis (HH) is a poor prognostic sign and is the main cause of death in the juvenile form. The treatment of choice is iron removal therapy by phlebotomy, but treatment by iron chelation (desferrioxamine) has been recommended in cases with severe cardiac symptoms. We describe here the first case of juvenile HH undergoing heart transplantation, which became necessary despite intensive iron removal therapy by phlebotomy and treatment by desferrioxamine. Throughout the course the myocardial iron content was monitored by endomyocardial biopsies and by magnetic resonance imaging (MRI). At the last follow-up, 18 months after transplantation, the myocardial iron content in the transplanted heart was still within reference ranges by biochemical determination and MRI and the patient's condition was completely satisfactory. In conclusion, heart transplantation should be considered in cases of severe juvenile HH. In the follow-up of these patients MRI may be a useful supplement.
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Affiliation(s)
- P D Jensen
- Department of Medicine, Aarhus Amtssygehus, Denmark
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35
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Jensen PD. [Organization of regulations. A leash on private wage developments. Negotiations 93]. Sygeplejersken 1992; 92:22-3. [PMID: 1297204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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36
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Jensen PD. [Labor market--women in jobs in Denmark and the EEC]. Sygeplejersken 1992; 92:18-22. [PMID: 1411967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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37
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Affiliation(s)
- P D Jensen
- University Department of Medicine and Haematology, Aarhus Amtssygehus, Denmark
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38
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Jensen PD. [Developments in the Scandinavian countries' nurses' salaries and employment conditions in the 80s]. Vard Nord Utveckl Forsk 1991; 11:36-9. [PMID: 1842334 DOI: 10.1177/010740839101100307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This article is based on a report published by the Northern Nurses' Federation (NNF) as background material for a conference on Nordic Nurses' Remuneration and Employment Conditions 22-24 October 1991, Denmark. The report contains an overview and analysis of data on nurses' remuneration and employment conditions obtained from the five Nordic nurses' associations: the Swedish Federation of Health Officers, the Danish Nurses' Organization, the Norwegian Nurses' Association, the Finnish Federation of Nurses and the Islandic Nurses' Association comprising the NNF. To make the report accessible for international use, English summaries have been added at the end of each chapter, and the headings of tables and figures are translated into English.
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39
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Jensen IM, Jensen PD, Ellegård J, Bastrup-Madsen P, Hokland P. [Extramedullary manifestations among adult patients with acute lymphoblastic leukemia (ALL)]. Ugeskr Laeger 1991; 153:1125-9. [PMID: 2024347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In 56 adult acute lymphoblastic leukemia (ALL) patients, 71% presented with extramedullary leukemic infiltration in lymphoid tissues (EML- spleen, liver, lymphnodes or thymus). EML was seen most often in patients with T-ALL (0.05 greater than p greater than 0.02) and in patients with high white blood counts (0.1 greater than p greater than 0.05). Surprisingly, these more often achieved complete remissions (0.1 greater than p greater than 0.05), of which both the duration and disease-free survival were longer. Thus, EML at diagnosis seems to be a favourable prognostic factor. At diagnosis, 23% of the patients had extramedullary leukemic infiltration in non-lymphoid tissue (EMIL-CNS, testis, skin, pleural cavities or gingiva). While more of these patients were of T-cell origin (61%, p less than 0.01), they were less likely to achieve CR, both the duration of remissions (p less than 0.01) as well as the disease free survival were shorter. Not unexpectedly, during the course of disease, the incidence of relapse localised at EMIL (the majority presenting in "sanctuary sites") increased, while that in the bone marrow decreased. Interestingly, in patients in CR presenting with EMIL, the first sign of relapse was unilateral peripheral facial paralysis in 60%. Finally, it should be stressed that the course of disease in patients presenting with simultaneous EML- and EMIL involvement was like that seen for EMIL patients. We conclude that while involvement of leukemia in EMIL represents a bad prognostic sign, the affection of leukemia in EML does not seem to confer a poorer prognosis, for adult ALL patients.
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Affiliation(s)
- I M Jensen
- Medicinsk-haematologisk afdeling 2, Arhus Amtssygehus
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40
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Jespersen M, Jensen PD. [Local wages. Do the counties not like nurses?]. Sygeplejersken 1990; 90:36-7. [PMID: 2089703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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41
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Stallknecht K, Jensen PD. [Danish Council of Nurses. Long-term wage strategy]. Sygeplejersken 1990; 90:30-3. [PMID: 2371682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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42
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Case CC, Roels SM, Jensen PD, Lee J, Kleckner N, Simons RW. The unusual stability of the IS10 anti-sense RNA is critical for its function and is determined by the structure of its stem-domain. EMBO J 1989; 8:4297-305. [PMID: 2480235 PMCID: PMC401638 DOI: 10.1002/j.1460-2075.1989.tb08616.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
IS10 transposition is regulated by an approximately 70 nt anti-sense RNA, RNA-OUT. RNA-OUT folds into a duplex 'stem-domain' topped by a loosely paired 'loop-domain'. The loop-domain is critical for RNA-RNA pairing per se; pairing initiates by interaction of the RNA-OUT loop with the 5' end of the target mRNA. We show here that RNA-OUT is unusually stable in vivo (half-life 60 min) and that this stability is conferred by specific features of the RNA-OUT stem-domain. One critical feature is stable base-pairing: mutations that disrupt stem pairing destabilize RNA-OUT in vivo and abolish anti-sense control; combinations of mutations that restore pairing also restore both stability and control. We propose that the stem renders RNA-OUT resistant to 3' exoribonucleases. Other features of the stem-domain prevent this essential duplex from being an effective substrate for double-strand nucleases: two single base mutations disrupt antisense control by making RNA-OUT susceptible to RNase III. Mutations in the loop region have little effect on RNA-OUT stability. Implications for IS10 biology and the design of efficient anti-sense RNAs are discussed.
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Affiliation(s)
- C C Case
- Department of Microbiology, University of California, Los Angeles 90024
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Jensen PD, Daugbjerg J. [Education. Announcement meets almost all our demands]. Sygeplejersken 1989; 89:8-10. [PMID: 2623579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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44
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Jensen PD. [Education. Now they expect a perspective committee]. Sygeplejersken 1989; 89:6-9. [PMID: 2749549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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45
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Jensen PD. [Need for reform of education in the health field]. Sygeplejersken 1989; 89:20-1. [PMID: 2741045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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46
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Stallknecht K, Jensen PD. [Nurses' proposal on pooled revenue sorted out]. Sygeplejersken 1988; 88:20-2. [PMID: 3217854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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47
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Palsbo S, Jensen PD. [Executive Board. Government's saving plan: reality or political rhetoric?]. Sygeplejersken 1988; 88:18-9, 23. [PMID: 3175910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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48
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Jensen PD. [Scandinavian Nurses' Association. New model for collective wage negotiations]. Sygeplejersken 1988; 88:28-31, 36. [PMID: 3394058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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49
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Jensen PD. [Many show willingness to test the pool system]. Sygeplejersken 1988; 88:30-1. [PMID: 3394031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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50
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Jensen PD. [Professional arguments for pool money to nurses]. Sygeplejersken 1988; 88:24-6. [PMID: 3388254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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