bluuebunny/crossref_metadata_2025 huggingface dataset:
The Antioxidant N-Acetylcysteine Induces Mesangial Cells to Create Three-Dimensional Cytoarchitecture That Underlies Cellular Differentiation
Authors: KITAMURA MASANORI
Published: April 2021

Prolonged culture of mesangial cells produces multifocal nodular structures, i.e., “hillocks,” consisting of cells and extracellular matrix. Hillock formation is associated with induction of a differentiated phenotype of mesangial cells, with suppressed mitogenesis and downregulation of α-smooth muscle actin (α-SMA). Currently, little is understood regarding physiologically relevant factors that facilitate this cytodifferentiation. This study explores whether and how the cellular redox state modulates hillock formation. Exposure of confluent rat mesangial cells to the antioxidant N-acetylcysteine (NAC), an inducer of glutathione, dramatically facilitated hillock formation. This effect was mimicked by external addition of the reduced form of glutathione ethyl ester. In contrast, the oxidizing agents diamide and menadione inhibited the development of hillocks triggered by either NAC, glutathione, or prolonged culture. The induction of hillocks by NAC was correlated with downregulation of α-SMA as well as attenuated activity of the CArG box element (the cis-element relevant to the expression of the α-SMA gene and growth-associated genes). These results indicate that, by a redox-sensitive mechanism, NAC induces mesangial cells to create three-dimensional cytoarchitecture that underlies cellular differentiation.
IFN-γ Mediates Crescent Formation and Cell-Mediated Immune Injury in Murine Glomerulonephritis
Authors: KITCHING A. RICHARD , HOLDSWORTH STEPHEN R. , TIPPING PETER G.
Published: April 2021

Features of crescentic glomerulonephritis suggest that it results from a T helper 1 (Th1) nephritogenic immune response. Interferon-γ (IFN-γ), produced by Th1 cells, is involved in T cell-directed macrophage activation in effector Th1 responses. The hypothesis that endogenous IFN-γ contributes to the development of crescentic glomerulonephritis was tested by comparing the development of glomerulonephritis (induced by a planted antigen) and immune responses in normal C57BL/6 mice (IFN-γ +/+) and in mice genetically deficient in IFN-γ (IFN-γ -/-). Ten days after the initiation of glomerulonephritis, IFN-γ -/- mice developed fewer glomerular crescents (5 ± 1% versus 26 ± 3%, P < 0.005), less severe glomerular injury, and less renal impairment. Effectors of delayed-type hypersensitivity (CD4+ T cells, macrophages, and fibrin) in glomeruli were reduced in IFN-γ -/- mice. Skin delayed-type hypersensitivity to sheep globulin was reduced. Total antigen-specific Ig and splenocyte interleukin-2 production were unchanged, but antigen-specific serum IgG2a was reduced. Markers of an antigen-specific Th2 response (serum IgG1, splenocyte interleukin-4) were unchanged. Studies 22 d after the initiation of glomerulonephritis showed that IFN-γ -/- mice still had fewer crescents (11 ± 2% versus 22 ± 3%, P = 0.02) and glomerular CD4+ T cells and macrophages than IFN-γ +/+ mice. These studies demonstrate that endogenous IFN-γ mediates crescentic glomerulonephritis by promoting cell-mediated immune injury. They support the hypothesis that crescentic glomerulonephritis is a manifestation of a Th1 nephritogenic immune response.
Underglycosylation of IgA1 Hinge Plays a Certain Role for Its Glomerular Deposition in IgA Nephropathy
Authors: HIKI YOSHIYUKI , KOKUBO TOHRU , IWASE HITOO , MASAKI YOSHIHIKO , SANO TAKASHI , TANAKA ATSUSHI , TOMA KAZUNORI , HOTTA KYOKO , KOBAYASHI YUTAKA
Published: April 2021

This study was performed to isolate and investigate the IgA1 that could accumulate in glomeruli (glomerulophilic IgA1). IgA1 was fractionated by the electric charge and the reactivity to Jacalin. Serum IgA1 of IgA nephropathy patients was separated and fractionated using a Jacalin column and subsequent ion-exchange chromatography. The fractions were divided into three groups of relatively cationic (C), neutral (N), and anionic (A). IgA1 was also divided into Jacalin low (L), intermediate (I), and high (H) affinity fractions by serial elution using 25, 100, and 800 mM galactose. The left kidneys of Wistar rats were perfused with 2, 5, or 10 mg of each group of IgA1. The rats were sacrificed 15 min, 30 min, 3 h, or 24 h after the perfusion. The accumulation of each IgA1 in the glomeruli was then observed by immunofluorescence. The IgA1 of the fractions N and H separated by the two methods was definitely accumulated in the rat glomeruli with a similar pattern. The electrophoresis revealed that the macromolecular IgA1 was increased in fraction H compared with other fractions. Therefore, Jacalin high-affinity IgA1 (fraction H) was applied on a diethylaminoethyl column and divided into electrically cationic (HC), neutral (HN), and anionic (HA). Only the asialo-Galβ1,3GalNAc chain was identified in the fraction HN IgA1 by gas-phase hydrazinolysis. Furthermore, the IgA1 fraction was strongly recognized by peanut agglutinin, Vicia Villosa lectins, and antisynthetic hinge peptide antibody. These results indicated that the IgA1 molecules having the underglycosylated hinge glycopeptide played a certain role in the glomerular accumulation of IgA1 in IgA nephropathy.
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

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

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

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

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

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

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

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

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

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

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

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

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.
Molecular Homology and the Luminal Transport of Hg2+ in the Renal Proximal Tubule
Authors: CANNON VERNON T. , BARFUSS DELON W. , ZALUPS RUDOLFS K.
Published: April 2021

The aim of this study was to define mechanisms involved in the luminal uptake of inorganic mercury in the kidney using isolated perfused straight (S2) segments of the proximal tubule. When mercuric conjugates of glutathione (GSH), cysteinylglycine, or cysteine (containing 203Hg2+) were perfused through the lumen, the rates of luminal disappearance flux (J
D) of inorganic mercury were approximately 39, 53, and 102 fmol/min per mm, respectively. Thus, the rates of luminal uptake of mercury are greater when the mercury is in the form of a mercuric conjugate of cysteine than in the form of a mercuric conjugate of cysteinylglycine or GSH. Addition of acivicin to the perfusate, to inhibit activity of the γ-glutamyltransferase, caused significant reductions in the J
D for mercury in tubules perfused with mercuric conjugates of GSH. Addition of cilastatin, an inhibitor of dehydropeptidase-1 (cysteinylglycinase) activity, caused significant reductions in the uptake of mercury in tubules perfused with mercuric conjugates of cysteinylglycine. These findings indicate that a significant amount of the luminal uptake of mercury, when mercuric conjugates of GSH are present in the lumen, is dependent on the activity of both γ-glutamyltransferase and cysteinylglycinase. Finally, the J
D for mercury in tubules perfused with mercuric conjugates of cysteine was reduced by approximately 50% when 3.0 mM L-lysine or 5.0 mM cycloleucine was added to the perfusate. It is concluded that these findings indicate that at least some of the luminal uptake of mercuric conjugates of cysteine occurs at the site of one or more amino acid transporters via a mechanism involving molecular homology.
Downregulation of SPARC Expression Is Mediated by Nitric Oxide in Rat Mesangial Cells and during Endotoxemia in
Authors: WALPEN SEBASTIAN , BECK KARL-FRIEDRICH , EBERHARDT WOLFGANG , APEL MARTINA , CHATTERJEE PRABAL K. , WRAY GILLIAN M. H. , THIEMERMANN CHRISTOPH , PFEILSCHIFTER JOSEF
Published: April 2021

Nitric oxide (NO) has been implicated in several forms of glomerulonephritis. In this study, a low stringency reversed transcription/PCR protocol was used to evaluate the action of NO on the mRNA expression pattern in rat mesangial cells (MC). To mimic the state of glomerular inflammation, MC were stimulated by exposure to the cytokines interleukin-1β and tumor necrosis factor-α into producing high levels of NO via expression of inducible nitric oxide synthase (NOS). To detect NO-mediated effects, the resulting expression pattern was compared to that of MC stimulated by the cytokines in the presence of the NOS inhibitor N
G-monomethyl-L-arginine (L-NMMA). Computer analysis of a differentially expressed cDNA fragment resulted in a 100% homology to the recently characterized mRNA of SPARC (secreted protein acidic and rich in cysteine). Further characterization of SPARC regulation revealed a cytokine- and cAMP-dependent decrease in SPARC mRNA and protein levels. Blocking NO formation by L-NMMA reversed the effects of cytokines and cAMP on SPARC expression, suggesting an NO-mediated mechanism. The NO donors S-nitroso-N-acetyl-penicillamine and diethyl-enetriamine/NO further reduced SPARC expression in cytokine-treated MC as well as in controls. Moreover, downregulation of SPARC mRNA and protein expression in whole kidneys obtained from rats treated with endotoxin was observed. This downregulation of SPARC was reversed by treatment with L-N
6-l (iminoethyl) lysine dihydrochloride, a potent and highly selective inhibitor of inducible NOS. These data characterize SPARC as an NO-regulated gene. This observation may be important in the context of tissue remodeling in chronic inflammatory kidney diseases.
Lipoprotein(a) in the Nephrotic Syndrome
Authors: DOUCET CHANTAL , MOOSER VINCENT , GONBERT SOPHIE , RAYMOND FRANC[COMBINING CEDILLA]OISE , CHAPMAN JOHN , JACOBS CLAUDE , THILLET JOËLLE
Published: April 2021

Plasma levels of lipoprotein(a) (Lp(a)), an atherogenic particle, are elevated in kidney disease, which suggests a role of this organ in the metabolism of Lp(a). Additional evidence for a role of the kidney in the clearance of Lp(a) is provided by the fact that circulating N-terminal fragments of apolipoprotein(a) (apo(a)) are processed and eliminated by the renal route. To further understand the mechanism underlying such renal excretion, the levels of apo(a) fragments in plasma and urine relative to plasma Lp(a) levels were determined in patients with nephrotic syndrome (n = 15). In plasma, the absolute (24.7 ± 20.4 versus 2.16 ± 2.99 μg/ml, P < 0.0001) as well as the relative amounts of apo(a) fragments (4.6 ± 3.4% versus 2.1 ± 3.3% of total Lp(a), P < 0.0001) were significantly elevated in nephrotic patients compared with a control, normolipidemic population. In addition, urinary apo(a) excretion in patients with nephrotic syndrome was markedly elevated compared with that in control subjects (578 ± 622 versus 27.7 ± 44 ng/ml per mg creatinine, P < 0.001). However, the fractional catabolic rates of apo(a) fragments were similar in both groups (0.68 ± 0.67% and 0.62 ± 0.47% in nephrotic and control subjects, respectively), suggesting that increased plasma concentrations of apo(a) fragments in nephrotic subjects are more dependent on the rate of synthesis rather than on the catabolic rate. Molecular analysis of apo(a) immunoreactive material in urine revealed that the patterns of apo(a) fragments in nephrotic patients were distinct from those of control subjects. Full-length apo(a), large N-terminal apo(a) fragments similar in size to those present in plasma, as well as C-terminal fragments of apo(a) were detected in urine from nephrotic patients but not in urine from controls. All of these apo(a) forms were in addition to smaller N-terminal apo(a) fragments present in normal urine. This study also demonstrated the presence of Lp(a) in urine from nephrotic patients by ultracentrifugal fractionation. These data suggest that in nephrotic syndrome, Lp(a) and large fragments of apo(a) are passively filtered by the kidney through the glomerulus, whereas smaller apo(a) fragments are secreted into the urine.
Naltrexone Does Not Relieve Uremic Pruritus
Authors: PAULI-MAGNUS CHRISTIANE , MIKUS GERD , ALSCHER DOMINIK M. , KIRSCHNER TILLMANN , NAGEL WILFRIED , GUGELER NADJA , RISLER TEUT , BERGER ELKE D. , KUHLMANN ULRICH , METTANG THOMAS
Published: April 2021

Improvement of uremic pruritus was reported under short-term administration of the μ-receptor antagonists naltrexone and naloxone. The aim of the present study was to confirm the efficacy and safety of the oral μ-receptor antagonist naltrexone during a 4-wk treatment period in patients on hemodialysis and peritoneal dialysis. A placebo-controlled, double-blind crossover study of uremic patients with persistent, treatment-resistant pruritus was performed. Of 422 patients screened between December 1997 and June 1998, 93 suffered from pruritus and 23 were eligible for the study. Patients were started either with a 4-wk naltrexone sequence (50 mg/d) or matched placebo. This was followed by a 7-d washout, and patients continued with a 4-wk sequence of the alternate medication. Pruritus intensity was scored daily by a visual analogue scale (VAS) and weekly by a detailed score assessing scratching activity, distribution of pruritus, and frequency of pruritus-related sleep disturbance. Sixteen of 23 patients completed the study. During the naltrexone period, pruritus decreased by 29.2% (95% confidence interval [CI], 18.7 to 39.6) on the VAS and by 17.6% (95% CI, 4.2 to 31.1) on the detailed score. In comparison, pruritus decreased by 16.9% (95% CI, 6.8 to 26.9) on the VAS and by 22.3% (95% CI, 9.3 to 35.2) on the detailed score during the placebo period. The difference between the naltrexone and the placebo treatment period was not statistically significant. Nine of 23 patients complained of gastrointestinal disturbances during the naltrexone period compared with only one of 23 patients during the placebo period (P < 0.05). These results show that treatment of uremic pruritus with naltrexone is ineffective. In addition, a high incidence of adverse effects was observed during treatment with naltrexone.
Validation of Comorbid Conditions on the End-Stage Renal Disease Medical Evidence Report
Authors: LONGENECKER J. CRAIG , CORESH JOSEF , KLAG MICHAEL J. , LEVEY ANDREW S. , MARTIN ALICE A. , FINK NANCY E. , POWE NEIL R.
Published: April 2021

Since 1995, the Medical Evidence Report for endstage renal disease (Form 2728) has been used nationally to collect information on comorbid conditions. To date, these data have not been validated. A national cross-sectional study of 1005 incident dialysis patients (734 hemodialysis and 271 peritoneal dialysis) enrolled between October 1995 and June 1998 was conducted using clinical data to validate 17 comorbid conditions on Form 2728. Sensitivity and specificity were calculated for each condition. The relationship between patient characteristics and sensitivity was assessed in multivariate analysis. Sensitivity was fairly high (0.67 to 0.83) for HIV disease, diabetes, and hypertension; intermediate (0.40 to 0.52) for peripheral vascular disease, neoplasm, myocardial infarction, cerebrovascular disease, coronary artery disease, cardiac arrest, and congestive heart failure; and poor (<0.36) for dysrhythmia, ambulation status, pericarditis, chronic obstructive pulmonary disease, and smoking. Sensitivity did not change significantly over calendar time. The sensitivity of Form 2728 averaged across all 17 conditions was 0.59 (95% confidence interval, 0.43 to 0.75). The average sensitivity was 0.10 greater in peritoneal dialysis than hemodialysis patients, 0.11 greater in diabetic patients than nondiabetic patients, and 0.04 less with each added comorbid condition. The specificity was very good for hypertension (0.91) and excellent (>0.95) for the other 16 conditions. Comorbid conditions are significantly underreported on Form 2728, but diagnoses are not falsely attributed to patients. Scientific research, quality of care comparisons, and payment policies that use Form 2728 data should take into account these limitations. Considerable effort should be expended to improve Form 2728 coding if it is to provide accurate estimates of total disease burden in end-stage renal disease patients.
Optimization of Epoetin Therapy with Intravenous Iron Therapy in Hemodialysis Patients
Authors: BESARAB ANATOLE , AMIN NEETA , AHSAN MUHAMMAD , VOGEL SUSAN E. , ZAZUWA GARY , FRINAK STANLEY , ZAZRA JAMES J. , ANANDAN J. V. , GUPTA AJAY
Published: April 2021

Iron deficiency limits the efficacy of recombinant human erythropoietin (rhEPO) therapy in end-stage renal disease (ESRD) patients. Functional iron deficiency occurs with serum ferritin >500 ng/ml and/or transferrin saturation (TSAT) of 20 to 30%. This study examines the effects of a maintenance intravenous iron dextran (ivID) protocol that increased TSAT in ESRD hemodialysis patients from conventional levels of 20 to 30% (control group) to those of 30 to 50% (study group) for a period of 6 mo. Forty-two patients receiving chronic hemodialysis completed a 16- to 20-wk run-in period, during which maintenance ivID and rhEPO were administered in amounts to achieve average TSAT of 20 to 30% and baseline levels of hemoglobin of 9.5 to 12.0 g/dl. After the run-in period, 19 patients randomized to the control group received ivID doses of 25 to 150 mg/wk for 6 mo. Twenty-three patients randomized to the study group received four to six loading doses of ivID, 100 mg each, over a 2-wk period to achieve a TSAT >30% followed by 25 to 150 mg weekly to maintain TSAT between 30 and 50% for 6 mo. Both regimens were effective in maintaining targeted hemoglobin levels. Fifteen patients in the control group and 17 patients in the study group finished the study in which the primary outcome parameter by intention to treat analysis was the rhEPO dose needed to maintain prestudy hemoglobin levels. Maintenance ivID requirements in the study group increased from 176 to 501 mg/mo and were associated with a progressive increase in serum ferritin to 658 ng/ml. Epoetin dose requirements for the study group decreased by the third month and remained 40% lower than for the control group, resulting in an overall cost savings in managing the anemia. Secondary indicators of iron-deficient erythropoiesis were also assessed. Zinc protoporphyrin did not change in either group. Reticulocyte hemoglobin content increased only in the study group from 28.5 to 30.1 pg. It is concluded that maintenance of TSAT between 30 and 50% reduces rhEPO requirements significantly over a 6-mo period.
Effect of Intravenous Fluids on Blood Pressure Course during Hemodialysis in Hypotensive-Prone Patients
Authors: VAN DER SANDE FRANK M. , LUIK ANTINUS J. , KOOMAN JEROEN P. , VERSTAPPEN VIC , LEUNISSEN KAREL M. L.
Published: April 2021

Hypertonic and hyperoncotic solutions are generally used as acute treatment for symptomatic hypotension during dialysis. Administration of hydroxyethylstarch (HES) was recently shown to be an effective substitution fluid in preserving blood volume (BV) and systolic BP (SBP) in a group of stable dialysis patients during dialysis. In this study, in nine cardiac-compromised dialysis patients with frequent symptomatic hypotensive episodes, the efficacy of three fluids (hypertonic saline [3%], albumin [20%], and HES [10%]) was assessed during three treatment sessions with combined ultrafiltration and hemodialysis, which only differed in the type of fluid administered intravenously. Changes in SBP and relative BV were compared. Fluids were given when SBP was less than 100 mmHg or when the decrease in SBP was more than 25 mmHg versus the start of the treatment. The ultrafiltration was continued at the same rate. When comparing SBP at the end of the dialysis session (t = end) with that at the time of infusion (t = iv), SBP decreased with saline, increased with albumin, and increased significantly with HES. The change in SBP in t = end versus t = iv was significantly greater when using saline compared with HES, and tended to decrease more when using saline compared with albumin (P = 0.09). Between albumin and HES there were no significant differences. BV decreased significantly (t = end) versus baseline (t = 0) during ultrafiltration and hemodialysis in all three treatment sessions. The decrease was significantly higher when using saline compared with albumin and saline compared with HES. Between albumin and HES there were no significant differences. When the values at t = end were compared with those at t = iv, BV decreased, although not significantly, with saline and albumin, but remained unchanged with HES. It is concluded that HES is an effective fluid in maintaining SBP and preserving BV in hypotensive-prone dialysis patients, comparable to albumin but superior to hypertonic saline.
An efficient synthetic approach for the transition metal-free preparation of 2-bromo-3-(bromomethyl)naphthalene from naphthalene
Authors: ERDOĞAN Musa
Published: April 2021

In this paper, a new efficient method for the synthesis of 2-bromo-3-(bromomethyl)naphthalene is reported. The synthesis is based on (1) preparation of 1,4-dihydronaphthalene via Birch reduction with mild conditions from the reaction of naphthalene, and (2) the reaction between 1,4-dihydronaphthalene and dichlorocarbene generated in situ from chloroform and t-BuOK, and (3) access to the key intermediate 1H-cyclopropa[b]naphthalene from the reaction of 1,1-dichloro-1a,2,7,7a-tetrahydro-1H-cyclopropa[b]naphthalene with t-BuOK, followed by ring-opening of the three-membered cyclopropane by bromination with molecular bromine (Br2). This synthetic sequence allows simple preparation of 2-bromo-3-(bromomethyl)naphthalene in higher yields compared to the two previously reported syntheses. The synthetic approach is modular, low cost, and rapid, and can be utilized to synthesize building blocks of naphthalene derivatives.
Teacher and actor perceptions of a recent journey involving clinical simulation
Authors: Carneiro Ana Cláudia , Aleluia Iêda , Fagundes Marília , Sestelo Maristela , Brasil Regina , Soares Tânia
Published: April 2021

INTRODUCTION: Medical education is under many modifications, insertions and new perspectives on the learning teaching process, and the realistic simulation is one of these changes. It includes technical skills, but also attitudinal skills. The original idea of simulation is to integrate theoretical knowledge, skills and attitude.  OBJECTIVES: to tell the experience of building a simulation core in our institution, with faculty development and culture changes. METHODS: using the cartography, 04 teachers and 02 female actors told their narratives by memories and reflections about the path travelled and the knowledge built. RESULTS AND DISCUSSION: each one experience on the first simulation scenario in 2018.2. We reached the original objective (students’ participation and study), but also the depth of each one experience and reflection. There was a balance between technique and sensibility. The actor’s role to build and concretize the project was essential in this balance. CONCLUSIONS: the simulation strengthened the attitudinal competences, promoted the faculty development and showed the importance to put together art and technique on the health professional training.
Impeachment, lawfare y fake news en Brasil. Un espejo latinoamericano
Authors: Böcker Zavaro Rafael
Published: April 2021

El propósito de este artículo es analizar en el caso de Brasil los mecanismos de poder del impeachment, el lawfare y las fake news, mecanismos que han sido también determinantes en otros procesos electorales recientes. Ello nos permite reflexionar sobre el actual escenario político latinoamericano, caracterizado por una mayoría de gobiernos de derecha liberal —conservadora o populista— identificados con políticas neoliberales.
Additional information for the creation of ahigh-quality draft genome for Melaleuca alternifolia (tea tree) v1
Authors: Voelker Julia
Published: April 2021

This protocol provides additional information to be read together with the publication about the genome assembly of Melaleuca alternifolia (tea tree). This is an extension to the methods listed in the manuscript, especially regarding the computational methods and specific commands that were used for genome assembly and annotation, as well as various quality control and filtering steps.