bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Normalization of Hematocrit on Brain Circulation and Metabolism in Hemodialysis Patients
Authors: METRY GEORGE , WIKSTRÖM BJÖRN , VALIND SVEN , SANDHAGEN BO , LINDE TORBJÖRN , BESHARA SOHEIR , LA[Combining Ring Above]NGSTRÖM BENGT , DANIELSON BO G. 
Published: April 2021

Abstract.
Full correction of anemia with recombinant human erythropoietin (rhEPO) has been reported to reduce the risk of cardiovascular morbidity and mortality and improve the quality of life in hemodialysis (HD) patients. Effects of normalization of hematocrit on cerebral blood flow and oxygen metabolism were investigated by positron emission tomography. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction ratio (rOER), and metabolic rate for oxygen (rCMRO2) were measured in seven HD patients before and after correction of anemia and compared with those in six healthy control subjects. In addition, blood rheology before and on rhEPO therapy was measured in HD patients, which included blood viscosity, plasma viscosity, erythrocyte fluidity, and erythrocyte aggregability. The results showed that plasma viscosity was high (1.51 ± 0.19 mPa · s) and erythrocyte fluidity was low (85.8 ± 4.8 Pa-1 · s-1), while whole blood viscosity was within the normal range (3.72 ± 0.38 mPa · s) before rhEPO therapy. After treatment, the hematocrit rose significantly from 29.3 ± 3.3 to 42.4 ± 2.2% (P < 0.001), accompanied by a significant increase in the whole blood viscosity to 4.57 ± 0.16 mPa · s, nonsignificant decrease in erythrocyte fluidity to 79.9 ± 7.4 mPa-1 · s-1 and nonsignificant change in plasma viscosity (1.46 ± 1.3 mPa · s). Positron emission tomography measurements revealed that by normalization of hematocrit, rCBF significantly decreased from 65 ± 11 to 48 ± 12 ml/min per 100 cm3 (P < 0.05). However, arterial oxygen content (caO2) significantly increased from 5.7 ± 0.7 to 8.0 ± 0.4 mmol/L (P < 0.0001), rOER of the hemispheres significantly increased from 44 ± 3 to 51 ± 6% (P < 0.05) and became significantly higher than healthy control subjects (P < 0.05). In addition, rCBV significantly increased from 3.5 ± 0.5 to 4.6 ± 0.6 ml/100 cc brain tissue. The results showed that oxygen supply to the brain tissue increased with normalization of hematocrit, but it was accompanied by increased oxygen extraction in the brain tissue. This may be assumed to be related to the decrease of erythrocyte velocity in the cerebral capillaries as a result of the decreased blood deformability and the increased plasma viscosity.
Suggestive Evidence for a Susceptibility Gene Near the Vitamin D Receptor Locus in Idiopathic Calcium Stone Formation
Authors: SCOTT PATRICK , OUIMET DENIS , VALIQUETTE LUC , GUAY GÉRALD , PROULX YANICK , TROUVE MARIE-LUCIE , GAGNON BERNARD , BONNARDEAUX ALAIN 
Published: April 2021

Abstract.
Calcium is the principal crystalline constituent in up to 80% of kidney stones. Epidemiologic studies have suggested that genetic predisposition plays a major role in the etiology of this condition. This study evaluates by a candidate-gene approach whether the vitamin D receptor (VDR) locus on chromosome 12q12-14 is implicated in idiopathic hypercalciuria and calcium nephrolithiasis in a cohort of 47 French Canadian pedigrees. These comprised 54 sibships with a total of 303 pairs of siblings concordant for ≥1 stone episode. Evidence is provided for linkage to nephrolithiasis with microsatellite marker D12S339 (near the VDR locus, P = 0.01), as well as with flanking markers (D12S1663: P = 0.03 and D12S368: P = 0.01). Inclusion of unaffected sibs in the analyses also supported evidence for linkage. Quantitative trait linkage analysis of urinary calcium excretion yielded linkage to some, but not all, markers. This appears to be the first study to suggest linkage for idiopathic calcium stone formation.
The Low Molecular Weight Apo(a) Phenotype Is an Independent Predictor for Coronary Artery Disease in Hemodialysis Patients
Authors: KRONENBERG FLORIAN , NEYER ULRICH , LHOTTA KARL , TRENKWALDER EVI , AUINGER MARTIN , PRIBASNIG ANDREAS , MEISL THOMAS , KÖNIG PAUL , DIEPLINGER HANS 
Published: April 2021

Abstract.
Patients with end-stage renal disease treated by hemodialysis have a tremendous risk for cardiovascular complications that cannot be explained by traditional atherosclerosis risk factors. Lipoprotein(a) (Lp(a)), a risk factor for these complications in the general population, is significantly elevated in these patients. In this study, it was determined whether Lp(a) and/or the genetically determined apo(a) phenotype are risk predictors for the development of coronary artery disease in these patients. A cohort of 440 unselected hemodialysis patients were followed for a period of 5 yr independent of the cause of renal disease, duration of preceding treatment, and the preexistence of coronary artery disease at study entry. Coronary events defined as definite myocardial infarction, percutaneous transluminal coronary angioplasty, aortocoronary bypass, or a stenosis >50% in the coronary angiography were the main outcome measure. Sixty-six (15%) of the 440 patients suffered a coronary event during follow-up. In univariate analysis, patients with events were significantly older and showed a trend to lower HDL cholesterol concentrations, and higher apolipoprotein B and Lp(a) concentrations without reaching significance. Apo(a) phenotypes of low molecular weight, however, were significantly more frequent in patients with compared to those without events (43.9% versus 21.9%, P < 0.001). The other lipids, lipoproteins, and apolipoproteins were similar in both groups. Multiple Cox proportional hazards regression analysis found age and the apo(a) phenotype to be the best predictors for coronary events during the observation period, independent of whether patients with a preexisting coronary artery disease or an age >65 yr at the study entry or both were excluded from the analysis. Diabetes mellitus was a risk factor only in presence of a low molecular weight apo(a) phenotype. The genetically determined apo(a) phenotype is a strong and independent predictor for coronary events in hemodialysis patients. Apo(a) phenotyping might be helpful to identify hemodialysis patients at high risk for coronary artery disease.
Na/K-ATPase in Intercalated Cells along the Rat Nephron Revealed by Antigen Retrieval
Authors: SABOLIĆ IVAN , HERAK-KRAMBERGER CAROL M. , BRETON SYLVIE , BROWN DENNIS 
Published: April 2021

Abstract.
The Na/K-ATPase plays a fundamental role in the physiology of various mammalian cells. In the kidney, previous immunocytochemical studies have localized this protein to the basolateral membrane in different tubule segments. However, intercalated cells (IC) of the collecting duct (CD) in rat and mouse were unlabeled with anti-Na/K-ATPase antibodies. An antigen retrieval technique has been recently described in which tissue sections are pretreated with sodium dodecyl sulfate before immunostaining. This procedure was used to reexamine the presence of Na/K-ATPase in IC along the rat nephron using monoclonal antibodies against the Na/K-ATPase α-subunit. Subtypes of IC along the nephron were identified by their distinctive staining with polyclonal and monoclonal antibodies to the 31-kD vacuolar H+-ATPase subunit, whereas principal cells (PC) were labeled with a polyclonal antibody to the water channel aquaporin-4 (AQP-4). In PC, the Na/K-ATPase and AQP-4 staining colocalized basolaterally. In contrast to previous reports, we found that IC of all types showed basolateral labeling with the anti-Na/K-ATPase antibody. The staining was quantified by fluorescence image analysis. It was weak to moderate in IC of cortical and outer medullary collecting ducts and most intense in IC of the initial inner medullary collecting duct. IC in the initial inner medulla showed a staining intensity that was equivalent or stronger to that in adjacent principal cells. Models of ion transport at the cellular and epithelial level in rat kidney, therefore, must take into account the potential role of a basolateral Na/K-ATPase in intercalated cell function.
Temporal Changes in mRNA Expression for Bikunin in the Kidneys of Rats during Calcium Oxalate Nephrolithiasis
Authors: IIDA SHIZUKA , PECK AMMON B. , JOHNSON-TARDIEU JOANNE , MORIYAMA MANABU , GLENTON PATRICIA A. , BYER KAREN J. , KHAN SAEED R. 
Published: April 2021

Abstract.
Inter-α-inhibitor and other bikunin-containing proteins are synthesized in relatively large quantities by the liver. These proteins function as Kunitz-type serine protease inhibitors and appear capable of inhibiting calcium oxalate (CaOx) crystallization in vitro. Preliminary studies have shown that renal tubular epithelial cells synthesize bikunin in response to CaOx challenge. To examine this response in vivo, a sensitive reverse transcription-quantitative competitive template-PCR was developed to detect and quantify poly(A)+ -tailed bikunin mRNA expression in kidney tissue from normal rats and rats developing CaOx nephrolithiasis after challenge with ethylene glycol. Bikunin mRNA expression in rat liver tissue was assessed as a positive control. The expression of bikunin mRNA in liver did not differ significantly between normal control rats and experimental rats with induced hyperoxaluria and renal CaOx crystallization. In contrast, there were significant temporal increases in the levels of bikunin mRNA expression in rat kidneys during CaOx nephrolithiasis after challenge with ethylene glycol. Urinary excretion of bikunin-containing proteins seemed to increase concomitantly. These findings indicate an association between the induction of hyperoxaluria/CaOx nephrolithiasis and the expression of the bikunin gene in rat kidneys.
Expression of Angiopoietin-1, Angiopoietin-2, and the Tie-2 Receptor Tyrosine Kinase during Mouse Kidney Maturation
Authors: YUAN HAI TAO , SURI CHITRA , YANCOPOULOS GEORGE D. , WOOLF ADRIAN S. 
Published: April 2021

Abstract.
The Tie-2 receptor tyrosine kinase transduces embryonic onic endothelial differentiation, with Angiopoietin-1 (Ang-1) acting as a stimulatory ligand and Ang-2 postulated to be a naturally occurring inhibitor. Expression of these genes was sought during mouse kidney maturation from the onset of glomerulogenesis (embryonic day 14 [E14]) to the end of nephron formation (2 wk postnatal [P2]), and during medullary maturation into adulthood (P8). Using Northern and slot blotting of RNA extracted from whole organs, these three genes were expressed throughout the experimental period with peak levels at P2 to P3. By in situ hybridization analysis at E18, P1, and P3, Ang-1 mRNA was found to localize to condensing renal mesenchymal cells, proximal tubules, and glomeruli in addition to maturing tubules of the outer medulla. In contrast, Ang-2 transcripts were more spatially restricted, being detected only in differentiating outer medullary tubules and the vasa recta bundle area. Using in situ hybridization and immunohistochemistry, Tie-2 was detected in capillaries of the nephrogenic cortex, glomerular tufts, cortical interstitium, and medulla including vessels in the vasa recta. Using Western blotting of protein extracted from whole organs, Tie-2 protein was detected between E14 and P8 with tyrosine phosphorylated Tie-2 evident from E18. These data are consistent with the hypothesis that Tie-2 has roles in maturation of both glomeruli and vasa rectae.
The In Vitro Effect of Calcitriol on Parathyroid Cell Proliferation and Apoptosis
Authors: CANALEJO ANTONIO , ALMADÉN YOLANDA , TORREGROSA VICENTE , GOMEZ-VILLAMANDOS JOSE C. , RAMOS BLANCA , CAMPISTOL JOSE M. , FELSENFELD ARNOLD J. , RODRÍGUEZ MARIANO 
Published: April 2021

Abstract.
Calcitriol treatment is used to reduce parathyroid hormone levels in azotemic patients with secondary hyperparathyroidism (HPT). Whether long-term calcitriol administration reduces parathyroid gland size in patients with severe secondary hyperparathyroidism is not clear. The aim of the study was to evaluate in vitro the effect of calcitriol on parathyroid cell proliferation and apoptosis in normal parathyroid glands and in adenomatous and hyperplastic human parathyroid glands. Freshly harvested parathyroid glands from normal dogs and hyperplastic and adenomatous glands from patients with secondary (2°) and primary (1°) HPT undergoing parathyroidectomy were studied. Flow cytometry was used to quantify the cell cycle and apoptosis of parathyroid cells. Apoptosis was also evaluated by DNA electrophoresis and light and electron microscopy. In normal dog parathyroid glands, culture with calcitriol (10-10 to 10-7 M) for 24 h produced a dose-dependent inhibitory effect on the progression of cells into the cell cycle and into apoptosis. When glands from patients with 2°HPT were cultured for 24 h, only high calcitriol concentrations (10-7 M) inhibited the progression through the cell cycle and the induction of apoptosis. In parathyroid adenomas (1°HPT), even a high concentration of calcitriol (10-7 M) had no significant effect on the cell cycle or apoptosis. The present study shows that in vitro, calcitriol inhibits in a dose-dependent manner in normal parathyroid glands both parathyroid cell proliferation and apoptosis. However, in secondary hyperplasia, only high concentrations of calcitriol inhibited cell proliferation and apoptosis. In 1°HPT, even high concentrations of calcitriol had no effect. Because calcitriol simultaneously inhibits both cell proliferation and apoptosis, a reduction in the parathyroid gland mass may not occur as a direct effect of calcitriol treatment.
Urinary Albumin Excretion Is Associated with Renal Functional Abnormalities in a Nondiabetic Population
Authors: PINTO-SIETSMA SARA-JOAN , JANSSEN WILBERT M.T. , HILLEGE HANS L. , NAVIS GERJAN , ZEEUW DICK DE , JONG PAUL E. DE 
Published: April 2021

Abstract.
Microalbuminuria (MA) is an important early sign of diabetic nephropathy. Hyperfiltration and impaired filtration in relation to albuminuria has been well investigated in diabetic subjects. This study tested the hypothesis that an increased urinary albumin excretion (UAE) is associated with renal functional abnormalities also in nondiabetic subjects. The relation between UAE and creatinine clearances (Ccr) in 7728 nondiabetic subjects was studied. Subjects were divided in four groups according to UAE (mg/24 h): 0 to 15 (control), 15 to 30 (high-normal albuminuria [HNA]), 30 to 300 (MA), >300 (macroalbuminuria). An elevated filtration and a diminished filtration were defined as a Ccr exceeding or below 2× the SD of the control group corrected for age and gender. Ccr followed a parabolic trend, with a higher Ccr in the HNA as compared with control and a lower Ccr in the MA and macroalbuminuria group as compared with HNA. With each increasing UAE level, male sex, age, body mass index, minimal waist circumference, systolic and diastolic BP, plasma glucose, and a positive family history for diabetes all followed a significant linear increasing trend (P < 0.001). After adjustment for age, gender, body mass index, plasma glucose, a positive family history for diabetes, systolic and diastolic BP, antihypertensive medication, and smoking in a multivariate analysis, HNA and MA were independently associated with an elevated filtration (RR 1.8 [95% confidence interval, 1.30 to 2.51] and 1.7 [1.17 to 2.45]). Macroalbuminuria was independently associated with a diminished filtration (4.3 [range, 1.97 to 9.36]). In conclusion, an elevated UAE might be an important and early sign for progressive renal function loss in a nondiabetic population.
Role of Lipoprotein (a) and TGF-β1 in Atherosclerosis of Hemodialysis Patients
Authors: FUJISAWA MASAHISA , HARAMAKI REIKO , MIYAZAKI HIROSHI , IMAIZUMI TSUTOMU , OKUDA SEIYA 
Published: April 2021

Abstract.
Atherosclerotic vascular disease is a major cause of death for uremic patients who are on hemodialysis (HD). Recent evidence suggests that lipoprotein (a) [Lp(a)] may aggravate atherosclerosis by inhibiting activation of transforming growth factor-β1 (TGF-β1). Plasma Lp(a) and plasma TGF-β1 activation in HD patients (n = 51), chronic renal failure patients not subjected to hemodialysis (non-HD-CRF; n = 12), and healthy volunteers (control; n = 13) were investigated. Plasma Lp(a) was significantly higher in HD (18.75 ± 1.62 mg/ml) and non-HD-CRF patients (25.0 ± 8.4 mg/ml) than in control subjects (10.9 ± 5.8 mg/ml). The degree of atherosclerosis in HD patients was assessed by measuring the intima-media thickness (IMT) and plaque score with the use of an ultrasound scanner. IMT and plaque score were higher in HD and non-HD-CRF patients than in controls. A significant positive correlation was found in HD patients between Lp(a) and IMT (r = 0.377, P < 0.01) as well as between Lp(a) and plaque score (r = 0.43, P < 0.01). Plasma total TGF-β1 significantly increased in HD (119.8 ± 53.5 ng/ml) and non-HD-CRF patients (93.2 ± 25.0 ng/ml) compared with control subjects (17.7 ± 6.4 ng/ml), whereas the plasma level of mature (active) TGF-β1 did not differ among the groups. When plasma TGF-β1 and supernatant TGF-β1 from cultured peripheral mononuclear cells were compared before and after an HD session, neither total nor mature TGF-β1 showed a significant difference between the values before and after an HD session. There were no significant relationships between plasma total TGF-β1 and IMT or plaque score, between mature TGF-β1 and IMT or plaque score, or between mature TGF-β1 and Lp(a). In conclusion, Lp(a) may be an important atherogenic factor in CRF patients. However, it was not clarified whether Lp(a) exerts its effect by inhibiting TGF-β1 activation in CRF patients.
Leptospira Outer Membrane Protein Activates NF-κB and Downstream Genes Expressed in Medullary Thick Ascending Limb Cells
Authors: YANG CHIH-WEI , WU MAI-SZU , PAN MING-JENG , HONG JENN-JYE , YU CHUN-CHEN , VANDEWALLE ALAIN , HUANG CHIU-CHING 
Published: April 2021

Abstract.
Tubulointerstitial nephritis is the main manifestation of acute renal damage caused by leptospirosis, but the mechanism remains unexplored. Patients infected with Leptospira shermani in Taiwan disclosed tubular dysfunction particularly in the medullary thick ascending limb of loop of Henle (mTAL), and the related renal damage seems to be underestimated. To elucidate the mechanism of tubular damage, outer membrane protein extract from Leptospira was administered to a model of cultured mTAL cells derived from normal mice. The addition of outer membrane protein extract from L. shermani to cultured mTAL cells induced a significant nuclear DNA binding of the NF-κ B transcription factor by electrophoresis mobility shift assay. Forty-eight h after adding the outer membrane protein extract (0.2 μg/ml) to the cultured cells, the expression of inducible nitric oxide mRNA increased by 4.2-fold, monocyte chemoattractant protein-1 by 3-fold, and tumor necrosis factor-α by 2.4-fold when compared with untreated cells examined by reverse transcription competitive-PCR. Supernatant nitrite, monocyte chemoattractant protein-1, and tumor necrosis factor-α protein levels also increased by 1.8-, 7.1-, and 5-fold, respectively. An antiserum raised against L. shermani largely prevented these effects. Outer membrane protein extract from L. bratislava induced fewer effects than L. shermani, and the avirulent nonpathogenic L. biflexa serovar patoc did not induce significant effects in the mTAL cells. In conclusion, L. shermani infection may cause mTAL cell damage and inflammation through the NF-κ B—associated pathway. Findings of this study may be important in understanding the pathogenesis of tubulointerstitial nephritis caused by these organisms.
Interleukin-17 and CD40-Ligand Synergistically Enhance Cytokine and Chemokine Production by Renal Epithelial Cells
Authors: WOLTMAN ANDREA M. , DE HAIJ SIMONE , BOONSTRA JOKE G. , GOBIN SAM J.P. , DAHA MOHAMED R. , KOOTEN CEES VAN 
Published: April 2021

Abstract.
Renal allograft rejection is characterized by an influx of inflammatory cells. Interaction between infiltrating T cells and resident parenchymal cells might play an important role in the ongoing inflammatory response. The present study demonstrates that CD40L, a product of activated T cells, is locally expressed in kidneys undergoing rejection. Furthermore, during rejection, CD40 expression not only is present on most graft infiltrating cells but also is increased on resident tubular epithelial cells (TEC). To obtain more detailed insight in the consequences of T cell/TEC interaction, we analyzed the production of chemokines, including interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and regulated upon activation, normal T cell expressed and secreted (RANTES), and the production of IL-6 by cultured human primary TEC in response to activation with CD40L in vitro. In addition, we studied the interaction with IL-17, a T-cell—specific cytokine previously demonstrated to be present during renal allograft rejection. The results, obtained by enzyme-linked immunosorbent assay, indicate that simultaneous activation of TEC with IL-17 and CD40L synergistically enhances production of IL-6 (2.1-fold higher than sum of single stimulations) and the chemokines IL-8 (15-fold) and RANTES (5.8-fold) as demonstrated by statistical analysis (P < 0.05), whereas effects on MCP-1 (1.4-fold) are additive. Part of the synergy can be explained by increased CD40 expression on TEC upon IL-17 stimulation. The synergy is not unique for TEC, because similar responses were found with human synoviocytes and a foreskin fibroblast cell line (FS4). Stimulation of TEC with CD40L results in activation of NF-κB and induction of cytokine production by IL-17 and CD40L is prevented by addition of the NF-κB inhibitor pyrrolidine dithiocarbamate. These data suggest an important role for T cells in renal allograft rejection by acting on parenchymal cells via both soluble mediators and direct cellular contact.
Evidence of Gene—Gene Interactions in the Genetic Susceptibility to Renal Impairment after Unilateral Nephrectomy
Authors: SHIOZAWA MASAHIDE , PROVOOST ABRAHAM P. , DOKKUM RICHARD P. E. VAN , MAJEWSKI REBECCA R. , JACOB HOWARD J. 
Published: April 2021

Abstract.
The number of patients with hypertension-associated end-stage renal failure (ESRF) continues to increase despite improved antihypertensive management and early detection programs. Variation for the development of renal complications in hypertension may reflect independent genetic susceptibility to ESRF. The genetically hypertensive fawn-hooded rat is characterized by the early presence of systolic hypertension, glomerular hypertension, progressive proteinuria (UPV), and focal glomerulosclerosis (FGS), resulting in premature death as a result of renal failure. In the present study, the genetic basis of hypertension-associated ESRF in an F2 intercross consisting of 337 animals, in which systolic BP, UPV, albuminuria, and FGS, were studied at 8 wk after a unilateral nephrectomy performed at 5 to 6 wk of age. A total genome scan, consisting of 418 markers, was used to identify regions that contribute to the pathogenesis of UPV and FGS. Linkage analysis revealed five loci involved in the development of renal impairment. Of these five, two (Rf-1, Rf-2) had been identified previously. There seems to be strong interactive effects between the various loci and their impact on UPV and the other parameters of renal impairment, as well as an interaction with BP. In particular, Rf-1 seems to play a major role in determining the severity of the disease. This study is the first to report the interaction of more than two loci to produce progressive renal failure, suggesting that the genetic dissection of renal failure in humans will require understanding of how multiple genes interact with each other and BP to produce ESRF.