bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dichotomous responses of inter and postprandial hyperglycaemia to short‐term calorie restriction in patients with type 2 diabetes
Authors: Colette C. , Ginet C. , Boegner C. , Benichou M. , Pham T. C. , Cristol J. P. , Monnier L. 
Published: April 2005

AbstractBackground  In type 2 diabetes the effects of short‐term calorie restrictions on glycaemia are usually judged on fasting plasma glucose. As fasting duration rarely exceeds 2–3 h, we determined the effects of calorie restriction over different daytime periods using a continuous glucose monitoring system (CGMS) in noninsulin‐using patients with type 2 diabetes.Design  Fourteen poorly controlled (mean HbA1c = 9·3%) overweight or obese patients (mean body mass index = 30·1 ± 0·7 kg m−2) with type 2 diabetes were investigated twice with a CGMS, at baseline and at the end of a 18‐day calorie‐restricted diet (1490 kcal day−1). Areas under curves (AUCs) of 24‐h glucose monitoring were measured and divided into postprandial and interprandial AUCs according to meal times.Results  Areas under curves of 24‐h glucose monitoring were significantly decreased after dieting: –37%, P = 0·0047. Both post and interprandial AUCs were significantly diminished (−26%, P = 0·0186 and −48%, P = 0·0037, respectively), but changes in interprandial AUCs were more marked than changes in postprandial AUCs (P = 0·0060). Nycthemeral peaks of glucose were observed at mid‐morning times and were not significantly different before (242 ± 15 mg dL−1) and after dieting (227 ± 16 mg dL−1).Conclusions  Short‐term calorie restriction in overweight or obese patients with type 2 diabetes resulted in dichotomous responses between interprandial and postprandial glycaemic excursions. The resistance of mid‐morning glucose peaking to calorie restriction should result in additional dietary or pharmacological measures at breakfast.
Tamm‐Horsfall protein: a multilayered defence molecule against urinary tract infection
Authors: Säemann M. D. , Weichhart T. , Hörl W. H. , Zlabinger G. J. 
Published: April 2005

AbstractUrinary tract infection (UTI) is the most common nonepidemic bacterial infection in humans, representing a constant danger for the host. Both innate and adaptive components of the immune system as well as stromal cells including bladder epithelium are involved in the prevention and clearance of UTI. However, the particular properties of the urogenital tract, which does not comprise typical physical barriers like a mucus or ciliated epithelium, necessitate soluble mediators with potent immunomodulatory capabilities. One candidate molecule capable of both mediating direct antimicrobial activity and alerting immune cells is the evolutionary conserved Tamm‐Horsfall protein (THP). Tamm‐Horsfall protein is exclusively produced by the kidney in the distal loop of Henle; however, its definite physiological function remains elusive. Mounting evidence indicates that beyond a mere direct antimicrobial activity, THP exerts potent immunoregulatory activity. Furthermore, the genetic ablation of the THP gene leads to severe infection and lethal pyelonephritis in an experimental model of UTI. Recent data are provided demonstrating that THP links the innate immune response with specific THP‐directed cell‐mediated immunity. In light of these novel findings we discuss the particular role of THP as a specialized defence molecule. We propose an integrated model of protective mechanisms against UTI where THP acts by two principle nonmutually exclusive mechanisms involving the capture of potentially dangerous microbes and the ability of this peculiar glycoprotein to induce robust protective immune responses against uropathogenic bacteria.
Pathogenesis, detection and treatment of Achilles tendon xanthomas
Authors: Tsouli S. G. , Kiortsis D. N. , Argyropoulou M. I. , Mikhailidis D. P. , Elisaf M. S. 
Published: April 2005

AbstractTendon xanthomatosis often accompanies familial hypercholesterolaemia, but it can also occur in other pathologic states. Achilles tendons are the most common sites of tendon xanthomas. Low‐density lipoprotein (LDL) derived from the circulation accumulates into tendons. The next steps leading to the formation of Achilles tendon xanthomas (ATX) are the transformation of LDL into oxidized LDL (oxLDL) and the active uptake of oxLDL by macrophages within the tendons. Although physical examination may reveal Achilles tendon xanthomas (ATX), there are several imaging methods for their detection. It is worth mentioning that ultrasonography is the method of choice in everyday clinical practice. Although several treatments for Achilles tendon xanthomas (ATX) have been proposed (LDL apheresis, statins, etc.), they target mostly in the treatment of the basic metabolic disorder of lipid metabolism, which is the main cause of these lesions. In this review we describe the formation, detection, differential diagnosis and treatment of ATX as well as the relationship between tendon xanthomas and atheroma.
Effects of simvastatin on blood lipids, vitamin E, coenzyme Q10 levels and left ventricular function in humans
Authors: Colquhoun D. M. , Jackson R. , Walters M. , Hicks B. J. , Goldsmith J. , Young P. , Strakosch C. , Kostner K. M. 
Published: April 2005

AbstractBackground  As statin therapy has been reported to reduce antioxidants such as vitamin E and coenzyme Q10 and there are indications that this reduction may cause impairment of left ventricular function (LVF), we studied the influence of simvastatin on LVF and serum vitamin E and coenzyme Q10 levels in humans.Material and methods  We assessed the effect of simvastatin on left ventricular function and coenzyme Q10 levels in 21 (11 male, 10 female) hypercholesterolaemic subjects (mean age = 56 years) with normal LVF, over a period of 6 months. Subjects were re‐tested after a 1‐month wash‐out period (7 months). Echocardiography was performed on all subjects before commencement of simvastatin (20 mg day−1), and at 1, 3, 6 and 7 months after initiation of treatment. Fasting blood samples were also collected at these intervals to assess lipids, apoproteins, vitamin E and coenzyme Q10.Results  Serum lipids showed the expected reductions. Plasma vitamin E and coenzyme Q10 levels were reduced by 17 ± 4% (P < 0·01) and 12 ± 4% (P < 0·03) at 6 months. However, the coenzyme Q10/LDL‐cholesterol ratio and vitamin E/LDL‐cholesterol ratio increased significantly. Left ventricular ejection fraction (EF) decreased transiently after 1 month, while no significant change was observed at 3 and 6 months. Other markers of left ventricular function did not change significantly at any time point.Conclusion  Despite reduced plasma vitamin E and coenzyme Q10, 20 mg of simvastatin therapy is associated with a significantly increased coenzyme Q10/LDL‐cholesterol ratio and vitamin E/LDL‐cholesterol ratio. Simvastatin treatment is not associated with impairment in left ventricular systolic or diastolic function in hypercholesterolaemic subjects after 6 months of treatment.
Increased glomerular and extracellular malondialdehyde levels in patients and rats with focal segmental glomerulosclerosis
Authors: Kuo H.‐T. , Kuo M.‐C. , Chiu Y.‐W. , Chang J.‐M. , Guh J.‐Y. , Chen H.‐C. 
Published: April 2005

AbstractBackground  Evidence suggests an increase in oxidative stress in patients with chronic kidney disease, as glomerulosclerosis is the prerequisite for chronic kidney disease; whether the oxidative stress already exists early on is not known.Materials and methods  In this study we measured the plasma and urinary levels of malondialdehyde (MDA), the end product of lipid peroxidation, and assessed the immunoreactivity of MDA and superoxide dismutase (SOD) in glomeruli of patients and rats with primary focal segmental glomerulosclerosis (FSGS), and compared our findings with those of minimal change disease (MCD) and normal controls (NC).Results  Our results showed that plasma MDA level was significantly increased in patients with FSGS compared with both patients with MCD and normal controls. The urinary MDA level was also significantly increased and was significantly correlated with plasma MDA level in patients with FSGS. The immunostaining for glomerular MDA and SOD was significantly higher in the patients with FSGS than in either the patients with MCD or NC, and was also significantly higher in rats with puromycin aminonucleoside (PAN)‐induced FSGS than in rats with MCD. Glomerular MDA level was significantly correlated with the degree of glomerulosclerosis in the patients with FSGS.Conclusions  Our data suggest that oxidative stress occurs early on before the onset of renal failure, and may play an important role in the pathogenesis of glomerulosclerosis.
Carbon fluxes, nitrogen cycling, and soil microbial communities in adjacent urban, native and agricultural ecosystems
Authors: Kaye J. P. , McCulley R. L. , Burke I. C. 
Published: April 2005

AbstractUrban ecosystems are expanding globally, and assessing the ecological consequences of urbanization is critical to understanding the biology of local and global change related to land use. We measured carbon (C) fluxes, nitrogen (N) cycling, and soil microbial community structure in a replicated (n=3) field experiment comparing urban lawns to corn, wheat–fallow, and unmanaged shortgrass steppe ecosystems in northern Colorado. The urban and corn sites were irrigated and fertilized. Wheat and shortgrass steppe sites were not fertilized or irrigated. Aboveground net primary productivity (ANPP) in urban ecosystems (383±11 C m−2 yr−1) was four to five times greater than wheat or shortgrass steppe but significantly less than corn (537±44 C m−2 yr−1). Soil respiration (2777±273 g C m−2 yr−1) and total belowground C allocation (2602±269 g C m−2 yr−1) in urban ecosystems were both 2.5 to five times greater than any other land‐use type. We estimate that for a large (1578 km2) portion of Larimer County, Colorado, urban lawns occupying 6.4% of the land area account for up to 30% of regional ANPP and 24% of regional soil respiration from land‐use types that we sampled. The rate of N cycling from urban lawn mower clippings to the soil surface was comparable with the rate of N export in harvested corn (both ∼12–15 g N m−2 yr−1). A one‐time measurement of microbial community structure via phospholipid fatty acid analysis suggested that land‐use type had a large impact on microbial biomass and a small impact on the relative abundance of broad taxonomic groups of microorganisms. Our data are consistent with several other studies suggesting that urbanization of arid and semiarid ecosystems leads to enhanced C cycling rates that alter regional C budgets.
Carbon exchange of grazed pasture on a drained peat soil
Authors: Nieveen Joost P. , Campbell David I. , Schipper Louis A. , Blair Ian J. 
Published: April 2005

AbstractLand‐use changes have contributed to increased atmospheric CO2 concentrations. Conversion from natural peatlands to agricultural land has led to widespread subsidence of the peat surface caused by soil compaction and mineralization. To study the net ecosystem exchange of carbon (C) and the contribution of respiration to peat subsidence, eddy covariance measurements were made over pasture on a well‐developed, drained peat soil from 22 May 2002 to 21 May 2003. The depth to the water table fluctuated between 0.02 m in winter 2002 to 0.75 m during late summer and early autumn 2003. Peat soil moisture content varied between 0.6 and 0.7 m3 m−3 until the water table dropped below 0.5 m, when moisture content reached 0.38 m3 m−3. Neither depth to water table nor soil moisture was found to have an effect on the rate of night‐time respiration (ranging from 0.4–8.0 μmol CO2 m−2 s−1 in winter and summer, respectively). Most of the variance in night‐time respiration was explained by changes in the 0.1 m soil temperature (r2=0.93). The highest values for daytime net ecosystem exchange were measured in September 2002, with a maximum of −17.2 μmol CO2 m−2 s−1. Grazing events and soil moisture deficiencies during a short period in summer reduced net CO2 exchange. To establish an annual C balance for this ecosystem, non‐linear regression was used to model missing data. Annually integrated (CO2) C exchange for this peat–pasture ecosystem was 45±500 kg C ha−1 yr−1. After including other C exchanges (methane emissions from cows and production of milk), the net annual C loss was 1061±500 kg C ha−1 yr−1.
Canopy‐scale δ13C of photosynthetic and respiratory CO2 fluxes: observations in forest biomes across the United States
Authors: Lai C.‐T. , Ehleringer J. R. , Schauer A. J. , Tans P. P. , Hollinger D. Y. , Paw U K. T. , Munger J. W. , Wofsy S. C. 
Published: April 2005

AbstractThe δ13C values of atmospheric carbon dioxide (CO2) can be used to partition global patterns of CO2 source/sink relationships among terrestrial and oceanic ecosystems using the inversion technique. This approach is very sensitive to estimates of photosynthetic 13C discrimination by terrestrial vegetation (ΔA), and depends on δ13C values of respired CO2 fluxes (δ13CR). Here we show that by combining two independent data streams – the stable isotope ratios of atmospheric CO2 and eddy‐covariance CO2 flux measurements – canopy scale estimates of ΔA can be successfully derived in terrestrial ecosystems. We also present the first weekly dataset of seasonal variations in δ13CR from dominant forest ecosystems in the United States between 2001 and 2003. Our observations indicate considerable summer‐time variation in the weekly value of δ13CR within coniferous forests (4.0‰ and 5.4‰ at Wind River Canopy Crane Research Facility and Howland Forest, respectively, between May and September). The monthly mean values of δ13CR showed a smaller range (2–3‰), which appeared to significantly correlate with soil water availability. Values of δ13CR were less variable during the growing season at the deciduous forest (Harvard Forest). We suggest that the negative correlation between δ13CR and soil moisture content observed in the two coniferous forests should represent a general ecosystem response to the changes in the distribution of water resources because of climate change. Shifts in δ13CR and ΔA could be of sufficient magnitude globally to impact partitioning calculations of CO2 sinks between oceanic and terrestrial compartments.
Site‐level evaluation of satellite‐based global terrestrial gross primary production and net primary production monitoring
Authors: Turner David P. , Ritts William D. , Cohen Warren B. , Maeirsperger Thomas K. , Gower Stith T. , Kirschbaum Al A. , Running Steve W. , Zhao Maosheng , Wofsy Steven C. , Dunn Allison L. , Law Beverly E. , Campbell John L. , Oechel Walter C. , Kwon Hyo Jung , Meyers Tilden P. , Small Eric E. , Kurc Shirley A. , Gamon John A. 
Published: April 2005

AbstractOperational monitoring of global terrestrial gross primary production (GPP) and net primary production (NPP) is now underway using imagery from the satellite‐borne Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Evaluation of MODIS GPP and NPP products will require site‐level studies across a range of biomes, with close attention to numerous scaling issues that must be addressed to link ground measurements to the satellite‐based carbon flux estimates. Here, we report results of a study aimed at evaluating MODIS NPP/GPP products at six sites varying widely in climate, land use, and vegetation physiognomy. Comparisons were made for twenty‐five 1 km2 cells at each site, with 8‐day averages for GPP and an annual value for NPP. The validation data layers were made with a combination of ground measurements, relatively high resolution satellite data (Landsat Enhanced Thematic Mapper Plus at ∼30 m resolution), and process‐based modeling. There was strong seasonality in the MODIS GPP at all sites, and mean NPP ranged from 80 g C m−2 yr−1 at an arctic tundra site to 550 g C m−2 yr−1 at a temperate deciduous forest site. There was not a consistent over‐ or underprediction of NPP across sites relative to the validation estimates. The closest agreements in NPP and GPP were at the temperate deciduous forest, arctic tundra, and boreal forest sites. There was moderate underestimation in the MODIS products at the agricultural field site, and strong overestimation at the desert grassland and at the dry coniferous forest sites. Analyses of specific inputs to the MODIS NPP/GPP algorithm – notably the fraction of photosynthetically active radiation absorbed by the vegetation canopy, the maximum light use efficiency (LUE), and the climate data – revealed the causes of the over‐ and underestimates. Suggestions for algorithm improvement include selectively altering values for maximum LUE (based on observations at eddy covariance flux towers) and parameters regulating autotrophic respiration.
Constitutive expression of yeast phospholipid biosynthetic genes by variants of Ino2 activator defective for interaction with Opi1 repressor
Authors: Heyken Willm‐Thomas , Repenning Antje , Kumme Jacqueline , Schüller Hans‐Joachim 
Published: April 2005

SummaryRegulated expression of structural genes involved in yeast phospholipid biosynthesis is mediated by inositol/choline‐responsive element (ICRE) upstream motifs, bound by the heterodimeric activator complex Ino2 + Ino4. Gene repression occurs in the presence of sufficient inositol and choline, requiring an intact Opi1 repressor which binds to Ino2. For a better understanding of interactions among regulators, we mapped an 18 aa repressor interaction domain (RID, aa 118–135) within Ino2 necessary and sufficient for binding by Opi1. By alanine scanning mutagenesis of the entire RID we were able to identify nine residues critical for Opi1‐dependent repression of Ino2 function. Consequently, the corresponding dominant Ino2 variants conferred constitutive expression of an ICRE‐dependent reporter gene and were no longer inhibited even by overproduction of Opi1. Interestingly, Ino2 RID partially overlaps with transcriptional activation domain TAD2. As certain mutations exclusively affect repression while others affect both repression and activation, both functions of Ino2 can be functionally uncoupled. Correspondingly, we mapped the RID–binding activator interaction domain (AID, aa 321–380) at the C‐terminus of Opi1 and introduced missense mutations at selected positions. An Opi1 variant simultaneously mutated at three highly conserved positions showed complete loss of repressor function, confirming RID–AID interaction as the crucial step of regulated expression of ICRE‐dependent genes.
Promoter architecture and response to a positive regulator of archaeal transcription
Authors: Ouhammouch Mohamed , Langham Geoffrey E. , Hausner Winfried , Simpson Anjana J. , El‐Sayed Najib M.A. , Geiduschek E. Peter 
Published: April 2005

SummaryThe archaeal transcription apparatus is chimeric: its core components (RNA polymerase and basal factors) closely resemble those of eukaryotic RNA polymerase II, but the putative archaeal transcriptional regulators are overwhelmingly of bacterial type. Particular interest attaches to how these bacterial‐type effectors, especially activators, regulate a eukaryote‐like transcription system. The hyperthermophilic archaeon Methanocaldococcus jannaschii encodes a potent transcriptional activator, Ptr2, related to the Lrp/AsnC family of bacterial regulators. Ptr2 activates rubredoxin 2 (rb2) transcription through a bipartite upstream activating site (UAS), and conveys its stimulatory effects on its cognate transcription machinery through direct recruitment of the TATA binding protein (TBP). A functional dissection of the highly constrained architecture of the rb2 promoter shows that a ‘one‐site’ minimal UAS suffices for activation by Ptr2, and specifies the required placement of this site. The presence of such a simplified UAS upstream of the natural rubrerythrin (rbr) promoter also suffices for positive regulation by Ptr2 in vitro, and TBP recruitment remains the primary means of transcriptional activation at this promoter.
SspA is required for acid resistance in stationary phase by downregulation of H‐NS in Escherichia coli
Authors: Hansen Anne‐Marie , Qiu Yu , Yeh Norman , Blattner Frederick R. , Durfee Tim , Jin Ding Jun 
Published: April 2005

SummaryThe stringent starvation protein A (SspA) is a RNA polymerase‐associated protein and is required for transcriptional activation of bacteriophage P1 late promoters. However, the role of SspA in gene expression in Escherichia coli is essentially unknown. In this work, we show that SspA is essential for cell survival during acid‐induced stress. Apparently, SspA inhibits stationary‐phase accumulation of H‐NS, a global regulator which functions mostly as a repressor, thereby derepressing multiple stress defence systems including those for acid stress and nutrient starvation. Consequently, the gene expression pattern of the H‐NS regulon  is  altered  in  the  sspA mutant,  leading  to acid‐sensitive and hypermotile phenotypes. Thus, our study indicates that SspA is a global regulator, which acts upstream of H‐NS, and thereby plays an important role in the stress response of E. coli during stationary phase. In addition, our results indicate that the expression of the H‐NS regulon is sensitive to small changes in the cellular level of H‐NS, enabling the cell to response rapidly to environment cues. As SspA and H‐NS are highly conserved among Gram‐negative bacteria, of which many are pathogenic, the global role of SspA in the stress response and pathogenesis is discussed.
Cholesterol binding by the bacterial type III translocon is essential for virulence effector delivery into mammalian cells
Authors: Hayward Richard D. , Cain Robert J. , McGhie Emma J. , Phillips Neil , Garner Matthew J. , Koronakis Vassilis 
Published: April 2005

SummaryA ubiquitous early step in infection of man and animals by enteric bacterial pathogens like Salmonella, Shigella and enteropathogenic Escherichia coli (EPEC) is the translocation of virulence effector proteins into mammalian cells via specialized type III secretion systems (TTSSs). Translocated effectors subvert the host cytoskeleton and stimulate signalling to promote bacterial internalization or survival. Target cell plasma membrane cholesterol is central to pathogen–host cross‐talk, but the precise nature of its critical contribution remains unknown. Using in vitro cholesterol‐binding assays, we demonstrate that Salmonella (SipB) and Shigella (IpaB) TTSS translocon components bind cholesterol with high affinity. Direct visualization of cell‐associated fluorescently labelled SipB and parallel immunogold transmission electron microscopy revealed that cholesterol levels limit both the amount and distribution of plasma membrane‐integrated translocon. Correspondingly, cholesterol depletion blocked effector translocation into cultured mammalian cells by not only the related Salmonella and Shigella TTSSs, but also the more divergent EPEC system. The data reveal that cholesterol‐dependent association of the bacterial TTSS translocon with the target cell plasma membrane is essential for translocon activation and effector delivery into mammalian cells.