bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organizations and Gene Duplications of the Human and Mouse MHC Complement Gene Clusters<sup>1</sup>
Authors: Yang Zhenyu , Yu C. Yung 
Published: April 2003

The MHC complement gene cluster (MCGC) in most people contains thirteen structural genes, pseudogenes and gene segments. Novel genes <i>RD</i>,<i> SKI2W</i>, <i>DOM3Z</i> and <i>RP1</i> are organized as two head-to-head gene pairs between complement gene <i>Bf</i> and the first locus of <i>C4. </i>Southern blot analysis shows that single-copy genes for <i>DOM3Z</i> are detectable in primates and other mammals. Sequence analyses revealed that the exon- intron structures of human and mouse <i>DOM3Z</i> genes are identical. Both human and mouse <i>DOM3Z</i> transcripts exhibit splice variants at the 5′ regions, although the open reading frames remain identical. Cloning and characterization of the mouse <i>RP1</i> cDNA revealed a reading frame for 254 amino acids with a bipartite nuclear localization signal close to the amino terminus. The mouse <i>RP1</i> gene consists of 7 exons and spans 12.9 kb. Located in intron 4 of mouse <i>RP1</i> is an endogenous retrovirus that probably confers the androgen-responsive expression of the Slp protein in certain male mice. The availability of the complete human and mouse MCGC genomic and cDNA sequences allows further deliberate analyses of gene duplications and evolution. The intergenic region between mouse <i>SLP</i> and <i>C4 </i>genes is more than six times larger than the corresponding region in humans. It contains the functional gene steroid <i>CYP21A</i>, long stretches of repetitive DNA elements, and three partially duplicated gene segments <i>TNXA</i>, <i>SKI2W2</i> and <i>RP2</i>. The modular duplications of human and mouse <i>RP-C4-CYP21-TNX</i> (RCCX) are sharply different as <i>SKI2W2</i> is absent in the human MCGC, and <i>TNXA</i> and <i>RP2 </i>are smaller in size but higher in sequence conservation in humans.
AT<sub>1</sub>-Receptor Antagonists Abolish Glomerular MCP-1 Expression in a Model of Mesangial Proliferative Glomerulonephritis
Authors: Wolf Gunter , Schneider André , Helmchen Udo , Stahl Rolf A.K. 
Published: April 2003

<b>Background:</b> Glomerular accumulation of macrophages/monocytes (M/M) is a typical early feature in the course of anti-thymocyte serum (ATS)-induced nephritis. We have previously shown that glomerular synthesis and expression of monocyte-chemoattractant protein-1 (MCP-1) occurs before influx of M/M and a neutralizing anti-MCP-1 antibody reduced this cell infiltrate by one third. The present study was undertaken to test the effect of two angiotensin II type 1 (AT<sub>1</sub>) receptor antagonists, losartan and irbesartan, on ATS-stimulated MCP-1 expression as well as glomerular influx of M/M. <b>Methods:</b> Treatment of rats with either losartan or irbesartan was started 24 h before administration of ATS. After 24 h, MCP-1 mRNA expression was evaluated by RT-PCR and Northern blots. MCP-1 protein was determined by Western blots and chemotactic factors released from isolated glomeruli were measured by chemotactic assay. Kidney sections were stained for rabbit IgG, complement C3, and M/M (ED1 antigen). <b>Results:</b> Both AT<sub>1</sub>-receptor antagonists caused a significant, but not total reduction in MCP-1 mRNA and protein expression 24 h after injection of ATS. Treatment with losartan or irbesartan also reduced the chemotactic activity of isolated glomeruli from nephritic animals. Quantification of ED1-positive cells revealed that losartan as well as irbesartan reduced glomerular M/M invagination in nephritic rats by approximately 30–50%. However, treatment with AT<sub>1</sub>-receptor antagonists did not influence binding of ATS to mesangial cells and subsequent complement activation indicating that the attenuated MCP-1 expression is not due to differences in delivery and binding of ATS to mesangial cells. <b>Conclusion:</b> Our data indicate that short-term antagonism of AT<sub>1</sub> receptors abolished the early glomerular MCP-1 expression and M/M influx. These results indicate that angiotensin II may exert immunomodulatory effects in vivo and adds a new mechanism showing how this vasopeptide may be involved in the pathogenesis of renal diseases.
Angiotensin II Blockade Limits Tubular Protein Overreabsorption and the Consequent Upregulation of Endothelin 1 Gene in Experimental Membranous Nephropathy
Authors: Zoja Carla , Liu Xue-Hui , Abbate Mauro , Corna Daniela , Schiffrin Ernesto L. , Remuzzi Giuseppe , Benigni Ariela 
Published: April 2003

Proteinuric renal diseases are associated with excessive renal synthesis of endothelin 1 (ET-1) either in experimental animals or humans. This has been interpreted as an upregulation of ET-1 gene in proximal tubular cells secondary to overreabsorption of an unusual amount of filtered proteins. Here we used a model of chronic proteinuria, passive Heymann nephritis (PHN), to localize the structure of the kidney responsible for excessive ET-1 expression and synthesis and to clarify whether drugs that reduce glomerular protein trafficking modified the distribution of ET-1 mRNA and the corresponding peptide in the kidney. PHN was induced in Sprague-Dawley rats after injection of rabbit anti-Fx1A antibody. Group 1 (n = 5) was untreated, group 2 (n = 5) was given daily the angiotensin-converting enzyme inhibitor lisinopril (40 mg/l) plus the angiotensin II receptor antagonist L-158,809 (50 mg/l) from day 7 – when rats were already proteinuric – to month 12. An additional group of normal rats (n = 5) was used as controls. Urinary excretion of ET-1 was significantly increased in PHN rats as compared with controls and normalized by the treatment. By in situ hybridization a weak signal for ET-1 mRNA was detectable in glomeruli, distal tubular segments, and proximal tubules of control kidneys. By contrast, a strong labeling was found in the kidneys of rats with PHN which was mainly localized to proximal tubules and renal interstitium. The pattern of renal ET-1-like immunoreactivity was remarkably consistent with ET-1 mRNA expression. In animals with PHN given the angiotensin II blocking therapy, the urinary excretion of proteins normalized, and the structural integrity of the kidney was well preserved. In the kidney tissue taken from these animals, both ET-1 mRNA and protein staining were quite comparable to controls. These data suggest a link between excessive protein tubular reabsorption and enhanced renal ET-1 in chronic nephropathies and provide a novel explanation for the renoprotective effect in vivo of drugs that, by blocking the biological activity of angiotensin II, reduce glomerular protein traffic and possible deleterious effects of excessive tubular protein overloading.
Production of Inflammatory Mediators and Cytokine Responsiveness of an SV40-Transformed Human Proximal Tubular Epithelial Cell Line
Authors: Gerritsma Jort S.J. , van Kooten Cees , Gerritsen Arnout F. , Mommaas A. Mieke , van Es Leendert A. , Daha Mohamed R. 
Published: April 2003

Proximal tubular epithelial cells (PTEC) play a central role in the physiology of the renal tubulointerstitium. To be able to study the relationship between tubular cells and inflammatory renal diseases the availability of cultured cells is of importance. This study describes an immortalized proximal tubular epithelial cell line which was generated using SV40 DNA. To determine whether the transformation altered the cell line, the transformed cell line was characterized phenotypically using different monoclonal antibodies directed against peptidases, which are characteristic of PTEC, such as adenosine deaminase binding protein (CD26), leucine amino peptidase and carboxy peptidase M by immunofluorescent staining and FACS analysis. All peptidases were clearly present on the parental cell line and the transformed cell line. However, the level of expression of the peptidases was lower on the transformed cell line as compared to the parental nontransfected cells. The morphology of the transformed cell line, determined using a transwell culture system and electron microscopy, showed a polarized morphology of the tubular cells, tight junctions and microvilli. The transformed cell line was compared with the parental proximal tubular epithelial cells in its ability to respond to inflammatory cytokines such as IL-1α, TNF-α, IFN-γ. Stimulation with these cytokines resulted in enhanced production of complement components C2, C3, C4 and factor H, IL-6 and the chemokines IL-8 and MCP-1. The transformed cell line responded in a similar fashion as the parental cell line, although the amount of the different proteins produced was significantly higher in the transformed cell line. Overall, the transformed tubular cell line seems to be a suitable model to study different effects on tubular cells in relation to inflammatory kidney diseases.
Quantitative Morphology of Renal Cortical Structures during Compensatory Hypertrophy
Authors: Pfaller Walter , Seppi Thomas , Ohno Akihiro , Giebisch Gerhard , Beck Franz X. 
Published: April 2003

The compensatory hypertrophy in different renal cortical structures was studied in rats 10 and 21 days after unilateral nephrectomy (UNX). Quantitative morphological/stereological analysis revealed significant increases in total renal cortical volume – 33% on day 10 and 48% on day 21 – after UNX. These changes were paralleled by significant increments in the volumes of proximal convoluted tubule (PCT, 55%), distal convoluted tubule (DCT, 114%), and cortical collecting duct (CCD, 106%) segments on day 10. The corresponding changes on day 21 were 76, 122, and 212%, respectively. These alterations were accompanied by increases in segment length; 3% PCT, 23% DCT, and 50% CCD on day 10 and 9% PCT, 30% DCT, and 142% CCD on day 21 after UNX. The total luminal and basolateral cell membrane surface areas also exhibited a time-dependent increase after UNX. The increments in both luminal and basolateral membrane domains in PCT and DCT after 10 days were not significant, but reached significance after 21 days (PCT: luminal membrane 21%, basolateral membrane 63%; DCT: luminal membrane 98%, basolateral membrane 63%). In contrast, CCD membrane areas had increased substantially already 10 days after UNX (luminal membrane 92%, basolateral membrane 71%). It declined subsequently by day 21 (luminal membrane 57%, basolateral membrane 32%). The cell rubidium concentration after a 30-second rubidium infusion, an index of Na-K-ATPase activity, as well as sodium concentrations were unaltered in cells of all nephron segments investigated. Altogether the stereological analysis shows that the compensatory increase in organ volume can be attributed primarily to an increase in nephron epithelial volume. The PCT responds with ‘radial’ hypertrophy (thickening of the tubular epithelial wall), while the DCT undergoes ‘length’ hypertrophy (increase of tubular length without thickening of the tubular wall and without an increase in number of cells). This type of hypertrophy is especially prominent on day 21 after UNX for the CCD which doubles in length. Only on day 10 does the CCD seem to respond with hyperplasia. Adaptive changes in response to UNX develop gradually. Only a few of the morphological parameters studied had completed their change by 10 days, the majority required longer.
Ultrastructure of the Vacuolar Apparatus in the Renal Proximal Tubule Microinfused in vivo with the Cytological Stain Light Green
Authors: Cui Shiying , Mata Lucinda , Maunsbach Arvid B. , Christensen Erik Ilsø 
Published: April 2003

To obtain insight into the basic mechanisms controlling endocytosis, we tested the effects of different perfusates containing the cytological stain light green on endocytosis and ultrastructure of the vacuolar apparatus in renal proximal tubule cells. Rat proximal tubules were microinfused in vivo for 2 min in the presence or absence of light green with the following solutions: (A) perfusates containing inorganic salts and (B) perfusates with organic components or protein. In other experiments, the tubules were first microinfused for 2 min with 0.9% NaCl in the presence or absence of light green, then 15 min later further microinfused with or without light green using either group A or B solutions in order to either aggravate or reverse possible changes. All infused tubules were fixed after 5 min with 1% glutaraldehyde and examined by electron microscopy. In tubules microinfused without light green, the endocytic vacuolar apparatus in the apical cytoplasm showed a normal ultrastructure. However, microinfusion of solutions containing light green in either inorganic salts or a low concentration of protein caused significant changes in the apical endocytic apparatus. Large endocytic vacuoles were absent, and invaginations and small endocytic vacuoles were decreased in frequency. On the other hand, the amount of dense apical tubules was significantly increased, and in some cells dense apical tubules had transformed into a cisternalike network. These changes were aggravated in tubules which received a second microinfusion of NaCl and reversed in tubules that received a second infusion of protein. Furthermore, in the tubules microinfused with light green using perfusates containing organic components or protein, the apical cytoplasm of proximal tubule cells showed an essentially normal endocytic apparatus. The present study demonstrates that microinfusion of renal proximal tubules with light green disrupted normal endocytic membrane trafficking and recycling. These changes could be prevented or reversed by microinfusion of solutions containing protein or organic components.
Accelerated Recovery of Glycerol-Induced Acute Renal Failure in Rats with Previous Partial Hepatectomy
Authors: Homsi Eduardo , Pires de Oliveira Dias Eliana , Figueiredo Jose Francisco , Gontijo Jose Antonio 
Published: April 2003

Several studies have reported a favorable effect following the administration of growth factors during the course of acute renal failure. To evaluate the effect of an increased endogenous production of growth factors, rats underwent 70% hepatectomy before glycerol-induced acute renal failure. The renal function was then monitored 12 and 48 h after glycerol injection in conscious rats. Twelve hours after the induction of acute renal failure, a reduction in creatinine clearance and sodium reabsorption was seen in both prehepatectomized and sham-hepatectomized rats. At 48 h, there was total recovery of glomerular filtration and tubular function in the prehepatectomized rats, whereas the sham-hepatectomized rats still had reduced glomerular filtration and sodium reabsorption. In rats treated with dexamethasone before hepatectomy and studied 48 h after the induction of acute renal failure, the protective action on renal function seen in prehepatectomized rats was totally blocked. A semiquantitative histological analysis done 48 h after the induction of acute renal failure demonstrated a fourfold increase in the number of necrotic tubules in both sham-hepatectomized and dexamethasone-treated rats as compared with hepatectomized rats. It is concluded that partial hepatectomy, a maneuver used to increase the endogenous synthesis of growth factors, accelerates recovery of renal function following glycerol-induced acute renal failure.
Effect of Human Natural Xenoantibody Depletion and Complement Inactivation on Early Pig Kidney Function
Authors: Cruzado Josep M. , Torras Joan , Riera Marta , Condom Enric , Lloberas Núria , Herrero Immaculada , Martorell Jaume , Grinyó Josep M. 
Published: April 2003

Preformed xenoreactive natural antibodies (XNA) and complement mediate hyperacute xenograft rejection (HXR) in pig-to-human discordant xenotransplantation. In a pig kidney-human blood xenoperfusion model, we investigated whether XNA depletion and/or human complement inactivation preserved early pig kidney function. Pig kidneys were perfused for 180 min with pig blood (AUTO group, n = 8), human blood (HETER group, n = 6), complement-inactivated human blood (COMi group, n = 5), XNA-depleted human blood (ABd group, n = 5) or complement-inactivated and XNA-depleted human blood (ABd&COMi group, n = 5). HETER kidneys were rejected after 15–30 min and showed vascular microthrombi and interstitial hemorrhages. XNA depletion and/or complement inactivation prevented HXR. The glomerular filtration rate in ABd, COMi and ABd&COMi groups was significantly lower than in the AUTO group. Also, beyond 60 min, the COMi group showed a significantly lower glomerular filtration rate than that observed in ABd and ABd&COMi groups. Kidneys from ABd, COMi and ABd&COMi groups displayed endothelial cell edema, as well as higher soluble P-selectin levels and a higher renal myeloperoxidase content than the AUTO group kidneys. COMi and ABd&COMi groups had a significantly lower renal myeloperoxidase level than the HETER group. Also, in contrast to HETER and ABd groups, these complement-inactivated groups failed to show a positive correlation between P-selectin and renal myeloperoxidase. We also investigated platelet-activating factor (PAF) as possible mediator for these functional and pathologic changes. We found that blood PAF levels were similar in HETER, ABd, COMi and ABd&COMi groups and significantly higher than in the AUTO group. Also, when PAF was added to porcine endothelial cell monolayers, morphological changes due to cytoskeleton contraction were observed, and these changes were prevented by preincubation with a PAF receptor antagonist. In conclusion, although depletion of XNA and/or complement inactivation prevent HXR, the pig kidney function is not preserved at the level of the autologous combination. The PAF overproduction observed in the xenogenic combination, which is independent of the presence of XNA and complement, may be, at least in part, responsible for early endothelial cell morphological changes still present when HXR is prevented.
Cadmium Nephrotoxicity Assessed in Isolated Rat Glomeruli and Cultured Mesangial Cells: Evidence for Contraction of Glomerular Cells
Authors: Barrouillet M.P. , Potier M. , Cambar J. 
Published: April 2003

Cadmium (Cd), an important pollutant, causes severe damage at the renal tubular level. Numerous previous studies have focused upon Cd tubular nephrotoxicity. The present study of Cd-induced glomerular damage examined the vasoactive effect of Cd in freshly isolated glomeruli and mesangial cells. Glomeruli were isolated by passing rat renal cortex pulp through calibrated sieves followed by culture for outgrowth of cells. Quantitative evaluation of glomerular and cellular contractions was performed by morphometric measurement of the area with an automatized image analyzer following different incubation times with Hanks’ balanced salt solution or Cd<sup>2+</sup>. Each glomerulus or mesangial cell served as its own control. Cd lethality was measured with microassay methods (neutral red, MTT uptake, and lactate dehydrogenase release), allowing the determination of an IC<sub>50</sub>. This ranged from 35 to 60 μ<i>M</i>. CdCl<sub>2</sub> induced a time-dependent contractile effect on isolated glomeruli; planar surface area decreases were 6.9% (1 μ<i>M</i>), 7.5% (0.1 μ<i>M</i>), and 7% (0.01 μ<i>M</i>). The decrease started as soon as Cd was in contact with glomeruli and ended 40 min later: T5 (2%), T10 (3.5%), T20 (4.2%), T30 (6.3%), T40 (7%). Cell size reduction was 19% (1 μ<i>M</i>), 14% (0.1 μ<i>M</i>), and 18% (0.01 μ<i>M</i>) and was also time-dependent. To confirm that contractile events occurred during the cell shape changes, examination of the mesangial α-actin network was performed concurrently. These results indicate that Cd contracts glomerular structures. This may, in part, explain the reduction in glomerular filtration seen in Cd nephrotoxicity.
Simultaneous Inhibition of Renal Phospholipase A<sub>2</sub> and Glutathione Synthesis by Manoalide and <i>DL</i>-Buthionine Sulfoximine Induces Acute Tubular Dysfunction in Rats
Authors: Soejima Akinori , Ishizuka Shunji , Miyake Nobuyuki , Fukuoka Kazuhito , Suzuki Michihiko , Kamiya Yasushi , Nagasawa Toshihiko 
Published: April 2003

We have previously demonstrated that gentamicin-induced acute renal failure is mediated by the consumption of renal glutathione (GSH) and accumulation of oxidized phospholipids in tubular epithelial cells as a result of inhibition of phospholipase A<sub>2</sub> (PLA<sub>2</sub>) activity. Based on these results, we tested the hypothesis that the simultaneous inhibition of PLA<sub>2</sub> and GSH synthesis induces acute renal failure similar in characteristics to gentamicin-induced acute renal failure. Male Sprague-Dawley rats kept under standard laboratory conditions were administered 3 mmol/kg of <i>DL</i>-buthionine sulfoximine (BSO; γ-glutamylcysteine synthetase inhibitor) and 30 μg/kg of manoalide (PLA<sub>2</sub> inhibitor), following which significant elevations in serum creatinine and urinary lysosomal enzyme levels (elevation of N-acetyl-β-<i>D</i>-glucosaminidase activity) were observed. The renal tissue GSH content was reduced in the group that received both BSO and manoalide as compared with the group that received manoalide alone. The renal tissue GSH content was also reduced in the group that received BSO alone. The renal tissue concentration of 2-thiobarbituric-acid-reactive substances increased rapidly, followed by an increase in renal tissue total phospholipid concentration in the group that received both BSO and manoalide. In contrast, the activity of PLA<sub>2</sub> in renal tissue decreased in the group that received both BSO and manoalide as compared with the groups that received BSO alone or physiological saline. In conclusion, concomitant administration of BSO and manoalide induces renal tubular damage and acute renal failure in rats, similar in characteristics to gentamicin-induced nephrotoxicity, whereas administration of BSO or manoalide alone did not. These results suggest that both inhibition of PLA<sub>2</sub> and GSH depletion are necessary for the induction of acute renal failure.
Preferential COX-2 Inhibitor, Meloxicam, Compromises Renal Perfusion in Euvolemic and Hypovolemic Rats
Authors: Birck R. , Krzossok S. , Knoll T. , Braun C. , van der Woude F.J. , Rohmeiss P. 
Published: April 2003

Nonsteroidal anti-inflammatory drugs can impair renal perfusion through inhibition of cyclooxygenase (COX)-mediated prostaglandin synthesis. We investigated the influence of the preferential COX-2 inhibitor, meloxicam (MELO), on renal hemodynamics in eu- and hypovolemic rats compared to the nonselective COX inhibitor indomethacin (INDO). The hypovolemic state was obtained in rats by three daily injections of furosemide (2 mg/kg i.p.) followed by a sodium-deficient diet for 7 days. In euvolemic rats (n = 6) neither INDO (5 mg/kg i.v.) nor MELO (1 or 2 mg/kg i.v.) influenced mean arterial blood pressure (MAP) or impaired renal (RBF) and cortical blood flow (CBF). Medullary blood flow (MBF) decreased after INDO (18%; p < 0.05), and dose-dependently after MELO (1 mg, 10%; 2 mg, 18%; p < 0.05). In hypovolemic rats (n = 6) INDO and MELO had no effect on MAP. RBF and CBF were reduced after INDO (11 or 20%; p < 0.05), but showed no changes after MELO. INDO induced a decrease in MBF (22%; p < 0.05) which was less pronounced after MELO (12%; p < 0.05). In conclusion the preferential COX-2 inhibitor MELO compromized renal perfusion in the outer medulla both in eu- and hypovolemic animals.