Infusion fluids contain harmful glucose degradation products

PURPOSE: Glucose degradation products (GDPs) are precursors of advanced glycation end products (AGEs) that cause cellular damage and inflammation. We examined the content of GDPs in commercially available glucose-containing infusion fluids and investigated whether GDPs are found in patients' blood. METHODS: The content of GDPs was examined in infusion fluids by high-performance liquid chromatography (HPLC) analysis. To investigate whether GDPs also are found in patients, we included 11 patients who received glucose fluids (standard group) during and after their surgery and 11 control patients receiving buffered saline (control group). Blood samples were analyzed for GDP content and carboxymethyllysine (CML), as a measure of AGE formation. The influence of heat-sterilized fluids on cell viability and cell function upon infection was investigated. RESULTS: All investigated fluids contained high concentrations of GDPs, such as 3-deoxyglucosone (3-DG). Serum concentration of 3-DG increased rapidly by a factor of eight in patients receiving standard therapy. Serum CML levels increased significantly and showed linear correlation with the amount of infused 3-DG. There was no increase in serum 3-DG or CML concentrations in the control group. The concentration of GDPs in most of the tested fluids damaged neutrophils, reducing their cytokine secretion, and inhibited microbial killing. CONCLUSIONS: These findings indicate that normal standard fluid therapy involves unwanted infusion of GDPs. Reduction of the content of GDPs in commonly used infusion fluids may improve cell function, and possibly also organ function, in intensive-care patients

Sealing of chromosomal DNA nicks during nucleotide excision repair requires XRCC1 and DNA ligase III alpha in a cell-cycle-specific manner

Impaired gap filling and sealing of chromosomal DNA in nucleotide excision repair (NER) leads to genome instability. XRCC1-DNA ligase IIIa (XRCC1-Lig3) plays a central role in the repair of DNA single-strand breaks but has never been implicated in NER. Here we show that XRCC1-Lig3 is indispensable for ligation of NER-induced breaks and repair of UV lesions in quiescent cells. Furthermore, our results demonstrate that two distinct complexes differentially carry out gap filling in NER. XRCC1-Lig3 and DNA polymerase d colocalize and interact with NER components in a UV- and incision-dependent manner throughout the cell cycle. In contrast, DNA ligase I and DNA polymerase are recruited to UV-damage sites only in proliferating cells. This study reveals an unexpected and key role for XRCC1-Lig3 in maintenance of genomic integrity by NER in both dividing and nondividing cells and provides evidence for cell-cycle regulation of NER-mediated repair synthesis in vivo

Recent Acceleration of Plastid Sequence and Structural Evolution Coincides with Extreme Mitochondrial Divergence in the Angiosperm Genus Silene

The angiosperm genus Silene exhibits some of the most extreme and rapid divergence ever identified in mitochondrial genome architecture and nucleotide substitution rates. These patterns have been considered mitochondrial specific based on the absence of correlated changes in the small number of available nuclear and plastid gene sequences. To better assess the relationship between mitochondrial and plastid evolution, we sequenced the plastid genomes from four Silene species with fully sequenced mitochondrial genomes. We found that two species with fast-evolving mitochondrial genomes, S. noctiflora and S. conica, also exhibit accelerated rates of sequence and structural evolution in their plastid genomes. The nature of these changes, however, is markedly different from those in the mitochondrial genome. For example, in contrast to the mitochondrial pattern, which appears to be genome wide and mutationally driven, the plastid substitution rate accelerations are restricted to a subset of genes and preferentially affect nonsynonymous sites, indicating that altered selection pressures are acting on specific plastid-encoded functions in these species. Indeed, some plastid genes in S. noctiflora and S. conica show strong evidence of positive selection. In contrast, two species with more slowly evolving mitochondrial genomes, S. latifolia and S. vulgaris, have correspondingly low rates of nucleotide substitution in plastid genes as well as a plastid genome structure that has remained essentially unchanged since the origin of angiosperms. These results raise the possibility that common evolutionary forces could be shaping the extreme but distinct patterns of divergence in both organelle genomes within this genus

Episodic Evolution and Adaptation of Chloroplast Genomes in Ancestral Grasses

It has been suggested that the chloroplast genomes of the grass family, Poaceae, have undergone an elevated evolutionary rate compared to most other angiosperms, yet the details of this phenomenon have remained obscure. To know how the rate change occurred during evolution, estimation of the time-scale with reliable calibrations is needed. The recent finding of 65 Ma grass phytoliths in Cretaceous dinosaur coprolites places the diversification of the grasses to the Cretaceous period, and provides a reliable calibration in studying the tempo and mode of grass chloroplast evolution.By using chloroplast genome data from angiosperms and by taking account of new paleontological evidence, we now show that episodic rate acceleration both in terms of non-synonymous and synonymous substitutions occurred in the common ancestral branch of the core Poaceae (a group formed by rice, wheat, maize, and their allies) accompanied by adaptive evolution in several chloroplast proteins, while the rate reverted to the slow rate typical of most monocot species in the terminal branches.Our finding of episodic rate acceleration in the ancestral grasses accompanied by adaptive molecular evolution has a profound bearing on the evolution of grasses, which form a highly successful group of plants. The widely used model for estimating divergence times was based on the assumption of correlated rates between ancestral and descendant lineages. However, the assumption is proved to be inadequate in approximating the episodic rate acceleration in the ancestral grasses, and the assumption of independent rates is more appropriate. This finding has implications for studies of molecular evolutionary rates and time-scale of evolution in other groups of organisms

Rapid Evolution of Enormous, Multichromosomal Genomes in Flowering Plant Mitochondria with Exceptionally High Mutation Rates

A pair of species within the genus Silene have evolved the largest known mitochondrial genomes, coinciding with extreme changes in mutation rate, recombination activity, and genome structure

Glucose degradation products in peritoneal dialysis fluids

Patients suffering from renal failure must remove extracellular water and waste products from their body in order to survive. One way of doing this is by treatment with peritoneal dialysis (PD). During PD treatment the abdominal cavity is filled and drained continuously with one to three liters of dialysis solution, often containing glucose, which act as an osmotic agent. Glucose creates a pressure gradient over the membrane which forces water and solutes to migrate from the blood into the dialysis fluid. During the production of these fluids, heat sterilization is a must in order to obtain a sterile product. During the heat sterilization glucose degrades to different carbonyl compounds named glucose degradation products (GDPs). GDPs are known to damage the peritoneum, might be responsible for ultrafiltration failure in patients and have a toxic impact on several in vivo systems such as generation of higher plasma advanced glycation end products, stimulation of growth factors (VEGF) and lower dialysate CA 125 levels. GDPs also display higher cytotoxicity in various in vitro systems. As a result, new biocompatible multicompartment PD fluids, low in GDPs, have been produced. The reason for the low concentrations of GDPs in these fluids is mainly a low pH (pH ? 3.1) in the glucose compartment in combination with a high glucose concentration during sterilization. The difference in the concentration of GDPs within and between the new biocompatible and the conventionally manufactured PD fluids is great. This is mainly due to different manufacturing conditions and different sterilization processes. 3,4-dideoxyglucosone-3-ene (3,4-DGE) is the most toxic GDP formed in PD fluids. Its toxicity has been confirmed in several in vitro studies, for example in inhibition of growth in cultured cell fibroblasts, retardation of wound healing, downregulation of zonula occludens protein 1 expression in mesothelial cells, inducing apoptosis in leukocytes and in renal tubular epithelial cells and suppressing effects on immune cells. 3,4-DGE exists in a temperature dependent equilibrium with a pool of 3-deoxyglucosone (3-DG) and 3-deoxyaldose-2-ene (3-DA). If stored above room temperature, the equilibrium in the pool changes and the concentration of 3,4-DGE increases, whereas 3-DG decreases (3-DA has not been identified in PD fluids). During storage and transport of conventional PD fluids short temperature impulses may rapidly form high amounts of 3,4-DGE from its pool making the fluid highly cytotoxic. As the temperature drops the concentration only slowly decreases. Therefore it is important to optimize different parameters during the manufacture of such fluids so as to minimize GDP formation, and a further important question concerns the temperatures at which the fluids are stored and transported before patient use

3,4-dideoxyglucosone-3-ene in peritoneal dialysis fluids infused into the peritoneal cavity cannot be found in plasma.

OBJECTIVE: Glucose degradation products (GDPs) are important for the outcome of peritoneal dialysis (PD) treatment. The most cytotoxic GDP found in conventionally manufactured fluids, 3,4-dideoxyglucosone-3-ene (3,4-DGE), may in addition be recruited from 3-deoxyglucosone (3-DG). What happens with the GDPs in the fluid infused into patients during PD is not known. We investigated whether 3,4-DGE and 3-DG in PD fluid can be found in plasma during treatment. DESIGN: Patients on PD were dialyzed with a conventional PD fluid containing 43 micromol/L 3,4-DGE and 281 micromol/L 3-DG. Parallel experiments were performed in rats and in vitro with human plasma. The rats were dialyzed with a PD fluid containing 100 micromol/L 3,4-DGE and 200 micromol/L 3-DG. RESULTS: The 3,4-DGE concentration in the peritoneum declined at a much higher rate during the dwell than did the 3-DG concentration. However, 3,4-DGE was not detected in the plasma of patients or of rats during dialysis. The 3-DG concentration in plasma peaked shortly after infusion of fluid into the peritoneal cavity. The 3,4-DGE concentration during experimental incubation in plasma declined rapidly; the 3-DG concentration declined only 10% as rapidly (or less). CONCLUSION: During dialysis, 3,4-DGE could not be detected in plasma of either PD patients or rats, presumably because of its high reactivity. On the other hand, 3-DG may pass through the membrane and be detected in the blood

3,4-dge in peritoneal dialysis fluids cannot be found in plasma after infusion into the peritoneal cavity.

OBJECTIVE: Glucose degradation products (GDPs) are important in the outcome of peritoneal dialysis (PD) treatment. 3,4-dideoxyglucosone-3-ene (3,4-DGE) is the most cytotoxic GDP found in conventionally manufactured fluids and may, in addition, be recruited from 3-deoxyglucosone (3-DG). It is not known what happens with those GDPs in patients during PD. The aim of this study was to investigate if the 3,4-DGE and 3-DG in PD fluids can be found in plasma during treatment. DESIGN: PD patients were dialyzed with a conventional PD fluid containing 43 mumol/L 3,4-DGE and 281 mumol/L 3-DG. Parallel experiments were performed in rats as well as in vitro with human plasma. The rats were dialyzed with a PD fluid containing 100 mumol/L 3,4-DGE and 200 mumol/L 3-DG. RESULTS: The concentration of 3,4-DGE in the peritoneum decreased at a much higher rate than 3-DG during the dwell. 3,4-DGE was not, however, detected in the plasma of patients or rats during dialysis. The concentration of 3-DG in plasma peaked shortly after infusion of the fluid to the peritoneal cavity. The concentration of 3,4-DGE during experimental incubation in plasma decreased rapidly, while the concentration of 3-DG decreased only 10% as rapidly or less. CONCLUSION: 3,4-DGE could not be detected in plasma from either PD patients or rats during dialysis. This is presumably due to its high reactivity. 3-DG may, on the other hand, pass through the membrane and be detected in the blood