| 21. |
- Kolsrud, Oscar, et al.
(författare)
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Measured and not estimated glomerular filtration rate should be used to assess renal function in heart transplant recipients.
- 2016
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Ingår i: Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association. - : Oxford University Press (OUP). - 1460-2385. ; 31:7, s. 1182-9
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Tidskriftsartikel (refereegranskat)abstract
- In organ transplanted patients, impaired renal function is of major prognostic importance and influences therapeutic decisions. Therefore, monitoring of renal function with glomerular filtration rate (GFR) is of importance, both before and after heart transplantation (HTx). The GFR can be measured directly (mGFR) or estimated (eGFR) with equations based on circulating creatinine or cystatin C levels. However, these equations have not been thoroughly validated in the HTx population.
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| 22. |
- Kolsrud, Oscar, et al.
(författare)
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Renal function and outcome after heart transplantation
- 2018
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 0022-5223. ; 155:4, s. 1593-1604.e1
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate whether measured glomerular filtration rate (mGFR) is a risk factor for death and/or end-stage renal disease (ESRD) after heart transplantation (HTx). Methods: All adult patients (n = 416) who underwent HTx between 1988 and 2010 were included. mGFR was performed both preoperatively and postoperatively as annual follow-up. Eight patients received a concomitant kidney transplant (KTx), and 15 underwent late KTx due to chronic renal failure after HTx. Results: The mean drop in mGFR compared with the preoperative value was 12% during the first year after HTx. Preoperative mGFR was not predictive of mortality or ESRD. Older or the use of a ventricular assist device (VAD) were preoperative predictors of death. Long-term survival was significantly worse in the patients who experienced a >25% decrease in mGFR during the first year after transplantation. The need for acute postoperative renal replacement therapy (RRT) was associated with impaired survival but did not predict ESRD among survivors. On multivariable analyses, previous heart surgery, preoperative VAD, and a lower mGFR were all predictors of RRT. In the most recent period, death without previous ESRD was lower, and the only preoperative factors associated with ESRD by multivariable analyses were mechanical ventilation and diabetes mellitus. Conclusions: Pretransplantation mGFR was not predictive of mortality or ESRD after HTx, but necessitated simultaneous or late-stage KTx in this selected population of patients. However, patients with a decrease in >25% mGFR during the first year post-transplantation, as well as early postoperative dialysis-dependent acute renal dysfunction, had a poor prognosis. We suggest that patients with severely impaired kidney function, irrespective of pretransplantation renal function, still should be considered for HTx, but also encourage careful interpretation of our results given the selection bias involved in this population.
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| 23. |
- Kromer, S, et al.
(författare)
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Regulation of the supply of cytosolic oxaloacetate for mitochondrial metabolism via phospho enolpyruvate carboxylase in barley leaf protoplasts .1. The effect of covalent modification on PEPC activity, pH response, and kinetic properties
- 1996
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - 0304-4165 .- 1872-8006. ; 1289:3, s. 343-350
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Tidskriftsartikel (refereegranskat)abstract
- The regulation of the supply of oxaloacetate (OAA) for mitochondrial metabolism via phosphoenolpyruvate carboxylase (PEPC) by covalent modification is studied in barley (Hordeum vulgare L.) leaf protoplasts in light or darkness as well as under photorespiratory or non-photorespiratory conditions. Extracts for studies on in vivo PEPC phosphorylation were prepared from barley leaf protoplasts by rapid filtration, fractionating the cell within less than 1 s. Measurements of in vitro PEPC activity were performed on samples quickly frozen in liquid nitrogen to break the cell and stop metabolism and thus preserve the in vivo activation state. The relative PEPC phosphorylation state increased upon illumination and decreased upon redarkening under photorespiratory and non-photorespiratory conditions. PEPC activity measured in the presence of malate (3 mM) under photorespiratory conditions showed the same response indicating that a light-induced increase in PEPC activity and decrease in malate sensitivity is caused by an increased phosphorylation level of the PEPC protein. PEPC activity was pH dependent. At the physiological cytosolic pH, activity was suboptimal, but most sensitive towards malate inhibition and glucose 6-phosphate stimulation. The presence of malate increased the sensitivity of PEPC activity towards pH changes. The response of PEPC activity to changing pH was not affected by changes in the activation state of the enzyme. The K-m (phosphoenolpyruvate, PEP) is about 1 mM. Upon illumination the K-m (PEP) decrease significantly. V-max was unaffected by the light treatment. The presence of physiological concentrations of glucose 6-phosphate decreased K-m (PEP) 5- to 10-fold and increased V-max by about 35%. The effect of glucose 6-phosphate was strongest (up to 7-fold) at subsaturating PEP concentrations stimulating PEPC activity to nearly maximal rates. The results show that an increase in PEPC phosphorylation state causes an increase in PEPC activity as well as in substrate affinity leading to an increased production of OAA in the light.
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| 24. |
- Kromer, S, et al.
(författare)
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Regulation of the supply of oxaloacetate for mitochondrial metabolism via phospho enolpyruvate carboxylase in barley leaf protoplasts .2. Effects of metabolites on PEPC activity at different activation states of the protein
- 1996
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Ingår i: Biochimica et Biophysica Acta - General Subjects. - 0304-4165 .- 1872-8006. ; 1289:3, s. 351-361
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Tidskriftsartikel (refereegranskat)abstract
- The regulation of the supply of oxaloacetate (OAA) for mitochondrial metabolism via phosphoenolpyruvate carboxylase (PEPC) by metabolites is studied in barley (Hordeum vulgare L.) leaf protoplasts in light or darkness as well as under photorespiratory or non-photorespiratory conditions. Measurements on PEPC activity were performed on samples quickly frozen in liquid nitrogen to break the cell and stop metabolism and thus preserve the in vivo activation state. Glycine, serine, pyruvate, acetyl-CoA, glycolate, fructose 1,6-bisphosphate, fructose 2,6-bisphosphate and ADP had no significant effect on PEPC activity. Malate, aspartate and glutamate were strong inhibitors of PEPC activity decreasing the activity more in light versus darkness. However, at the physiological cytosolic concentration of these metabolites under the respective conditions, inhibition of PEPC activity was about the same with the exception of aspartate which inhibits more under non-photorespiratory than under photorespiratory conditions. 2-Oxoglutarate and glyoxylate decreased PEPC activity by 20 to 40% in the range of its physiological cytosolic concentration. Inhibition by physiological cytosolic concentrations of glutamine was limited. Glucose B-phosphate, fructose B-phosphate, 3-phosphoglycerate, dihydroxyacetonphosphate and P-i stimulated PEPC activity significantly in their physiological cytosolic concentration range. Physiological cytosolic concentrations of glucose 6-phosphate and fructose 6-phosphate activated PEPC activity to about the same extent under all conditions applied, while 3-phosphoglycerate and dihydroxyacetonphosphate stimulating Stronger under non-photorespiratory versus photorespiratory conditions. Moreover, dihydroxyacetonphosphate stimulated PEPC activity more in light versus darkness under non-photorespiratory conditions. P-i activation of PEPC activity decreases in light versus darkness under non-photorespiratory conditions. Stimulation of PEPC activity by citrate in its physiological concentration range is limited. Glucose 1-phosphate and AMP activated PEPC activity only at concentrations higher than their physiological levels in the cytosol. Determinations of PEPC activity in the presence of different malate/glucose 6-phosphate ratios revealed that glucose 6-phosphate totally relieved the inhibitory effect of malate. The regulatory properties of PEPC activity will be discussed in relation to its functions in C-3 plants.
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| 25. |
- Larsson, S, et al.
(författare)
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Molecular cloning and biochemical characterization of carbonic anhydrase from Populus tremula x tremuloides
- 1997
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Ingår i: Plant Molecular Biology. - 0167-4412 .- 1573-5028. ; 34:4, s. 583-592
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Tidskriftsartikel (refereegranskat)abstract
- A leaf cDNA library from hybrid aspen, Populus tremula x tremuloides, was constructed. From this two different cDNA clones, denoted CAla and CAlb, encoding a chloroplastic carbonic anhydrase (CA) were isolated and DNA sequenced. Analysis of the deduced amino acid sequences showed that the isolated CAs belong to the beta-CA family, and have identities around 70% to other dicotyledonous plant CAs. The two hybrid aspen cDNA clones display a high nucleotide sequence identity, only 12 nucleotides differ. Since only one gene copy of this soluble chloroplastic CA is present in the nuclear genome, we postulate that the two isolated cDNA clones are alleles. Northern blot hybridization revealed a CA transcript of ca. 1300 bases, 140 bases shorter than in pea. Western and northern blot hybridizations on crude protein extracts and on total RNA, respectively, isolated from stem and leaves, showed that hybrid aspen CA is expressed specifically in the leaf under the growth conditions used. Based on the deduced amino acid sequence, the mature hybrid aspen CA enzyme subunit has a molecular mass of 24.8 kDa. The enzyme was over-expressed in Escherichia coli, and purified by affinity chromatography. Biochemical characterization showed that the protein structure and the CO2-hydration activity are similar to the pea enzyme. Molecular characterization of a CA from a perennial plant has not previously been performed, and it demonstrates that both the structure and activity of hybrid aspen CA resembles CAs from annual plants.
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| 26. |
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| 27. |
- Linder, Tomas, et al.
(författare)
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A family of putative transcription termination factors shared amongst metazoans and plants.
- 2005
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Ingår i: Current genetics. - : Springer Science and Business Media LLC. - 0172-8083 .- 1432-0983. ; 48:4, s. 265-9
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Tidskriftsartikel (refereegranskat)abstract
- The human mitochondrial transcription termination factor (mTERF) is involved in the regulation of transcription of the mitochondrial genome. Similarity searches and phylogenetic analysis demonstrate that mTERF is a member of large and complex protein family (the MTERF family) shared amongst metazoans and plants. Interestingly, we identify three novel MTERF genes in vertebrates, which all encode proteins with predicted mitochondrial localization. Members of the MTERF family have so far not been detected in fungi, supporting the notion that mitochondrial transcription regulation may have evolved separately in yeast and animal cells.
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| 28. |
- Moroney, J V, et al.
(författare)
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Carbonic anhydrases in plants and algae
- 2001
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Ingår i: Plant, Cell and Environment. - 0140-7791 .- 1365-3040. ; 24:2, s. 141-153
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Forskningsöversikt (refereegranskat)abstract
- Carbonic anhydrases catalyse the reversible hydration of CO2, increasing the interconversion between CO2 and HCO3- + H+ in living organisms. The three evolutionarily unrelated families of carbonic anhydrases are designated alpha-, beta -and gamma -CA. Animals have only the alpha -carbonic anhydrase type of carbonic anhydrase, but they contain multiple isoforms of this carbonic anhydrase. In contrast, higher plants, algae and cyanobacteria may contain members of all three CA families. Analysis of the Arabidopsis database reveals at least 14 genes potentially encoding carbonic anhydrases. The database also contains expressed sequence tags (ESTs) with homology to most of these genes. Clearly the number of carbonic anhydrases in plants is much greater than previously thought. Chlamydomonas, a unicellular green alga, is not far behind with five carbonic anhydrases already identified and another in the EST database. In algae, carbonic anhydrases have been found in the mitochondria, the chloroplast thylakoid, the cytoplasm and the periplasmic space. In C-3 dicots, only two carbonic anhydrases have been localized, one to the chloroplast stroma and one to the cytoplasm. A challenge for plant scientists is to identify the number, location and physiological roles of the carbonic anhydrases.
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| 29. |
- Nikitina, Julia, et al.
(författare)
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Importance of a single disulfide bond for the PsbO protein of photosystem II : protein structure stability and soluble overexpression in Escherichia coli.
- 2008
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Ingår i: Photosynthesis Research. - : Springer Science and Business Media LLC. - 0166-8595 .- 1573-5079. ; 98, s. 391-403
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Tidskriftsartikel (refereegranskat)abstract
- PsbO protein is an important constituent of the water–oxidizing complex, located on the lumenal side of photosystem II. We report here the efficient expression of the spinach PsbO in E. coli where the solubility depends entirely on the formation of the disulfide bond. The PsbO protein purified from a pET32 system that includes thioredoxin fusion is properly folded and functionally active. Urea unfolding experiments imply that the reduction of the single disulfide bridge decreases stability of the protein. Analysis of inter-residue contact density through the PsbO molecule shows that Cys51 is located in a cluster with high contact density. Reduction of the Cys28–Cys51 bond is proposed to perturb the packing interactions in this cluster and destabilize the protein as a whole. Taken together, our results give evidence that PsbO exists in solution as a compact highly ordered structure, provided that the disulfide bridge is not reduced.
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| 30. |
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