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Biomedical subjects

J Wada

Publications and source records attributed to J Wada.

At least 73 records · Page 4Linked to original sources
PubMed1998

Fatal hyperammonemia in a patient with systemic lupus erythematosus.

We treated a 31-year-old woman with systemic lupus erythematosus, renal failure with nephrotic syndrome, and a long-standing seizure disorder, who developed severe hyperammonemia with a fatal outcome. Blood chemistry examination did not indicate liver disease, and amino acid concentrations did not suggest a defect in the urea cycle. Discontinuation of anticonvulsant treatment with valproic acid (VPA) failed to bring about improvement. We speculated that hyperammonemia in this case was induced by VPA, and the existence of other underlying factors, including the administration of aspirin and cimetidine, hypoalbuminemia, and renal failure might elevate the concentration of the serum free fraction of VPA.

Adult↗
PubMed1997

Developmental regulation, expression, and apoptotic potential of galectin-9, a beta-galactoside binding lectin.

Galectin-9, a beta-galactoside binding lectin, has recently been isolated from murine embryonic kidney. In this study, its biological functions and expression in embryonic, newborn, and adult mice tissues were investigated. By Northern blot analyses, it was found widely distributed and its expression was developmentally regulated. In situ hybridization studies revealed an accentuated expression of galectin-9 in liver and thymus of embryonic mice. In postnatal mice, antigalectin-9 immunoreactivity was observed in various tissues, including thymic epithelial cells. The high expression of galectin-9 in the thymus led us to investigate its role in the clonal deletion of thymocytes. Fusion proteins were generated, which retained lactose-binding activity like the endogenous galectin-9. Galectin-9, at 2.5 microM concentration, induced apoptosis in approximately 30% of the thymocytes, as assessed by terminal deoxytransferase-mediated dUTP nick end labeling method. The apoptotic effect was dose dependent and lactose inhibitable. At higher concentrations, it induced homotypic aggregation of the thymocytes. Electron microscopy revealed approximately 60% of the thymocytes undergoing apoptosis in the presence of galectin-9. By immunofluorescence microscopy, some of the thymocytes undergoing apoptosis had plasmalemmal bound galectin-9. Galectin-9 failed to induce apoptosis in hepatocytes. Taken together, these findings indicate that galectin-9, a developmentally regulated lectin, plays a role in thymocyte-epithelial interactions relevant to the biology of the thymus.

Aging↗
PubMed1997

Identification and characterization of galectin-9, a novel beta-galactoside-binding mammalian lectin.

A 36-kDa beta-galactoside mammalian lectin protein, designated as galectin-9, was isolated from mouse embryonic kidney by using a degenerate primer polymerase chain reaction and cloning strategy. Its deduced amino acid sequence had the characteristic conserved sequence motif of galectins. Endogenous galectin-9, extracted from liver and thymus, as well as recombinant galectin-9 exhibited specific binding activity for the lactosyl group. It had two distinct N- and C-terminal carbohydrate-binding domains connected by a link peptide, with no homology to any other protein. Galectin-9 had an alternate splicing isoform, exclusively expressed in the small intestine with a 31-amino acid insertion between the N-terminal domain and link peptide. Sequence homology analysis revealed that the C-terminal carbohydrate-binding domain of mouse galectin-9 had extensive similarity to that of monomeric rat galectin-5. The presence of galectin-5 in the mouse could not be demonstrated by polymerase chain reaction or by Northern or Southern blot genomic DNA analyses. Sequence comparison of rat galectin-5 and rat galectin-9 cDNA did not reveal identical nucleotide sequences in the overlapping C-terminal carbohydrate-binding domain, indicating that galectin-9 is not an alternative splicing isoform of galectin-5. However, galectin-9 had a sequence identical with that of its intestinal isoform in the overlapping regions in both species. Southern blot genomic DNA analyses, using the galectin-9 specific probe derived from the N-terminal carbohydrate-binding domain, indicated the presence of a novel gene encoding galectin-9 in both mice and rats. In contrast to galectin-5, which is mainly expressed in erythrocytes, galectin-9 was found to be widely distributed, i.e. in liver, small intestine, thymus > kidney, spleen, lung, cardiac and skeletal muscle > reticulocyte, brain. Collectively, these data indicate that galectin-9 is a new member of the galectin gene family and has a unique intestinal isoform.

Amino Acid Sequence↗
PubMed1997

Oxidized LDLs but not native LDLs augment Ba2+ currents through L-type Ca2+ channels of the A7r5 smooth muscle-derived cell line.

The whole-cell patch-clamp method was used on A7r5 smooth muscle-derived cell line, and Ba2+ currents through Ca2+ channels were recorded. The A7r5 cells showed voltage-dependent, long-lasting Ba2+ currents which were markedly inhibited by nifedipine (10 microM). The magnitude of the maximum Ba2+ current (IBa(max)) was augmented by an application of dbcAMP (1 mM), but not affected by TPA (80 nM). Noradrenaline (NA) at 100 microM caused an increase in the IBa(max) by 19.7% in the presence of phentolamine (10 microM). This effect was cancelled by Rp-cAMPs (10 microM). In the presence of propranolol (10 microM), NA tended to reduce the IBa(max). Application of Ox-LDLs at 100 microg protein/ml caused an increase in the IBa(max) by 15.7%, whereas native LDLs did not change the IBa(max). Rp-cAMPs was ineffective to the Ox-LDL action on the IBa(max). In the presence of Ox-LDLs, NA augmented the IBa(max) by 21.4% in the presence of phentolamine. These results suggest that Ox-LDLs activate L-type Ca2+ channels of A7r5 cells by a mechanism independent of cAMP/PKA signalling.

Aorta↗
PubMed1997

Representational difference analysis of cDNA of genes expressed in embryonic kidney.

Representational difference analysis of cDNA (cDNA-RDA) is a PCR-based differential cloning method. It involves hybridization of two populations of cDNA with selective amplification of differentially expressed genes. To isolate the differentially expressed genes during renal development, mRNAs from embryonic kidneys at day 13 (E13) and postnatal kidneys from three-week-old (P3) mice were extracted, and double stranded cDNAs prepared. Double stranded cDNAs were digested with DpnII, adaptor-ligated, and amplified by PCR, using adaptor primer to generate "representative amplicons." These reflect the "representation" of most of the cDNA population. The term "amplicons" denotes amplified PCR product. Among the two populations of cDNA, E13 kidney cDNA was used as a "tester," containing target genes, and P3 kidney cDNA as a "driver," driving the process of subtraction, following which, they were subjected to cDNA-RDA under low stringency conditions. During the first round of cDNA-RDA embryonic globin genes were isolated. To competitively eliminate these genes, plasmid DNAs of globin genes were supplemented into driver, and subjected to the second round of cDNA-RDA. This resulted in the isolation of four cDNA clones: H19 gene, mesoderm-specific cDNA, COL2A1 gene, and a novel cDNA. By Northern blot analyses, the H19 gene and mesoderm-specific cDNA exhibited a high degree of developmental regulation, that is, they were abundantly expressed in E13 kidney, and their expression was barely detectable in P3 kidney. The differential developmental regulation of mesoderm-specific cDNA was confirmed by tissue in situ hybridization experiments. The COL2A1 and novel cDNA were rare transcripts in the embryonic Kidney. However, Southern blot analyses of representations indicated their up-regulated expressions in E13 kidneys. The novel gene was differentially expressed in 13-day embryonic lung, and Northern blot analysis revealed an approximately 10 Kb transcript. These results indicate that cDNA-RDA is a sensitive technique to identify rare transcripts with differential expression, and since there is a minimal chance to isolate false positive clones, cDNA-RDA may serve as a powerful tool for delineating up- or down-regulation of the genes involved in various pathological or physiological states of the kidney.

Amino Acid Sequence↗
PubMed1997

Developmental regulation and partial-length cloning of tubulointerstitial nephritis antigen of murine metanephros.

Tubulointerstitial nephritis antigen (TIN-ag) is an extracellular matrix (ECM) glycoprotein that has been recently isolated and cloned from the rabbit kidney. It is an integral component of the basal lamina, and unlike other basement membrane proteins it is exclusively expressed in the tubular basement membranes (TBMs). Since other ECM glycoproteins have been shown to regulate development of various organ systems, studies were initiated to ascertain its developmental regulation in renal tubulogenesis and glomerulogenesis. Embryonic (day-13 and -17 of gestation), newborn and one-week-old mice kidneys were harvested for expression of TIN-ag as well as cDNA cloning studies. Immunostaining with polyclonal anti-TIN-ag antibody revealed its localization to the basal lamina of ureteric bud branches and epithelial elements of developing nephrons in day-13 embryonic kidneys. Interestingly, it was heavily expressed at the tips of the ureteric bud branches, and was not expressed in the distal convolutions of the S-shaped body stage of the nephrons, the region which forms the future glomerulus. At day-17, TIN-ag expression was less, and the immuno-reactivity was mainly localized to the cortex. In the newborn and one-week-old mice kidneys, the cortical expression of TIN-ag increased progressively, but was absent in the glomeruli. The TIN-ag expression was confined to the cortical TBMs, while absent in the medullary tubules, the latter included segments of the collecting ducts and loop of Henle. Immunoprecipitation studies on [35S]methionine-labeled metanephroi revealed a single band of approximately 58 kDa at day-13, and the incorporated radioactivity decreased at day-17. No high molecular weight isoforms were observed. A partial-length mouse TIN-ag cDNA of approximately 530 bp PCR product was generated, and it had approximately 88% and approximately 93% nucleotide and amino acid sequence homolgy, respectively, with rabbit TIN-ag. Utilizing this cDNA, Northern blot analyses revealed a single transcript of approximately 2 Kb in fetal and postnatal mice kidneys. mRNA expression initially decreased at day-17, and then progressively increased by one week. Utilizing a mouse TIN-ag riboprobe, in situ hybridization studies revealed a generalized diffuse expression of TIN-ag in the epithelial clements of developing nephrons and ureteric bud branches at day-13. Gene expression decreased by day-17, and became confined to the renal cortex, and then progressively increased during the neo- and post-natal periods, but remained absent in the renal medulla and glomeruli. These data indicate that TIN-ag is expressed in the metanephros early in embryonic life in the absence of any detectable isoforms, and it exhibits spatio-temporal characteristics during metanephric development. Being concentrated at the tips of the ureteric bud branches, it is conceivably involved in epithelial:mesenchymal interactions which are highly prevalent during renal organogenesis, and its role in tubulogenesis diverges from glomerulogenesis at the S-shaped body stage of the nephron.

Amino Acid Sequence↗
PubMed1997

Changes in osteosclerosis of the osteoarthritic knee after high tibial osteotomy.

Radiographically demonstrated osteosclerosis was quantitatively evaluated in knees with medial compartmental osteoarthritis by dual xray absorptiometry. Bone density was measured in various areas of 144 knees with medial compartmental osteoarthritis, 23 knees of which were treated with high tibial osteotomy. The bone mineral density of the medial femoral and tibial condyles was greater than that of the lateral femoral and tibial condyles in all knees with medial compartmental osteoarthritis. The ratios of bone mineral density of the medial condyles to that of the lateral condyles were found to increase significantly with the progression of osteoarthritis. There was a significant positive regression line correlation between those ratios and the increase of varus deformity as expressed by the standing femorotibial angle. The former were calculated to be 1.0 when the latter was nearly 170 degrees (10 degrees anatomic valgus angulation). The ratio of bone mineral density of the medial femoral condyles to the lateral femoral condyles decreased sharply in all 23 knees within 1 year after high tibial osteotomy.

Absorptiometry, Photon↗
PubMed1997

Differential rates of age of seizure onset between sexes and between hemispheres?

In a descriptive analysis of 158 patients with temporal lobe epilepsy, Taylor (1969) reported that the age of first seizure varied systematically as a function of laterality and sex. We conducted inferential analyses of Taylor's original data which (1) provided support for his proposal of disproportionate left hemisphere vulnerability to seizure onset in early life, but (2) failed to provide evidence of sex differences in age of onset of unilateral seizures. Examination of these effects in a larger sample of 844 patients drawn from the Bozeman Epilepsy Consortium provided some additional support for findings from the inferential analysis. Specifically, the left hemisphere appeared more vulnerable to seizure onset in childhood, this increased vulnerability extending to about age 5 years. Age of onset of seizures was not different when males and females were compared. Thus, reanalysis of Taylor's original data as well as examination of data from a larger, more contemporary sample suggest that seizure onset varies as a function of laterality, but not sex.

Adult↗
PubMed1996

D-glucose-induced dysmorphogenesis of embryonic kidney.

An organ culture system was used to study the effect of D-glucose on embryonic kidneys, and to delineate the mechanism(s) relevant to their dysmorphogenesis. Metanephroi were cultured in the presence of 30 mM D-glucose. A notable reduction in the size and population of nephrons was observed. Ureteric bud branches were rudimentary and the acuteness of their tips, the site of nascent nephron formation, was lost. Metanephric mesenchyme was atrophic, had reduced cell replication, and contained numerous apoptotic cells. Competitive reverse transcriptase-PCR analyses and immunoprecipitation studies indicated a decrease in expression of heparan sulfate proteoglycan (perlecan). Status of activated protein-2 was evaluated since its binding motifs are present in the promoter region of the perlecan gene. Decreased binding activity of activated protein-2, related to its phosphorylation, was observed. D-glucose-treated explants also had reduced levels of cellular ATP. Exogenous administration of ATP restored the altered metanephric morphology and reduced [35S]sulfate-incorporated radioactivity associated with perlecan. The data suggest that D-glucose adversely affects the metanephrogenesis by perturbing various cellular phosphorylation events involved in the transcriptional and translational regulation of perlecan. Since perlecan modulates epithelial/mesenchymal interactions, its deficiency may have led to the metanephric dysmorphogenesis and consequential atrophy of the mesenchyme exhibiting accelerated apoptosis.

Actins↗
PubMed1996

Comparative role of phosphotyrosine kinase domains of c-ros and c-ret protooncogenes in metanephric development with respect to growth factors and matrix morphogens.

Receptor-like protooncogenes, with tyrosine kinase catalytic domains, are expressed in neoplastic and fetal tissues and potentially have a role in embryonic development. Which protooncogene may have the dominant role in embryonic renal development during the "postinductive" period, i.e., Day 10 onward, was addressed in this study by utilizing an in vitro organ culture system. The role of various receptor-like protooncogenes, with the emphasis on c-ros and c-ret, was investigated by antisense-oligodeoxynucleotide (ODN) gene-targeting strategies at a point in metanephric development when reciprocal-inductive interactions between the epithelium and mesenchyme have already been initiated and are rampant. Also, their relationship with other morphogens, like extracellular matrix (ECM) proteins and growth factors, was studied. Initial in situ hybridization and RT-PCR analyses revealed a similar spatiotemporal expression for both c-ros and c-ret in the embryonic kidneys. At Day 13, they were mainly expressed in the developing nephrons in the nephrogenic zone and ureteric bud branches, where the signals from the mesenchymal ligands are transduced to the epithelial cell surface receptors. Minimal expression was observed in the newborn kidneys. Inclusion of antisense ODNs, derived from the phosphotyrosine kinase domains, inhibited metanephric growth in the organ culture; the most dramatic effects were observed with the c-ret antisense ODN. The c-ret-induced dysmorphogenetic effects were characterized as a decrease in the population of nephrons, atrophy of the mesenchymal cells, and loss of acuteness of the tips of ureteric bud branches. Interestingly, the ureteric bud branches continue to grow in the atrophic mesenchyme. Both c-ros and c-ret antisense ODNs reduced the gene expression and biosynthesis of various ECM proteins. The proteoglycans, expressed at the epithelial:mesenchymal interface, were most adversely affected, especially by the c-ret antisense. The treatment of metanephric explants with c-ret did not affect the gene expression of c-ros and vice versa. The specificity of the effects of c-ret antisense was also reflected by a decrease of anti-Ret protein immunoreactivity. The studies were extended to establish a relationship between c-ret protooncogene and some of the growth factors which are known to influence renal development via their tyrosine kinase-like receptors localized in the ureteric bud branches, the site apparently where c-ret is also expressed. Among the various growth factors examined, transforming growth factor-alpha (TGF-alpha) and insulin like growth factor-I (IGF-I) had the most notable trophic effects on metanephric explants and caused maximal phosphorylation of Ret protein. In addition, concurrent exposure of TGF-alpha or IGF-I and c-ret antisense ODN explants caused partial recovery from the c-ret-induced dysmorphogenetic effects in the metanephroi. The data suggest that, although a number of protooncogenes share similar catalytic domains, c-ret plays a major role during the "postinductive" period of metanephric development by perturbing the growth factor-dependent expression of ECM morphogenetic macromolecules, notably that of the proteoglycans, and also by affecting certain yet undefined growth factor-mediated phosphorylation mechanism(s) involving c-ret.

Animals↗
PubMed1996

Thimerosal modulates the agonist-specific cytosolic Ca2+ oscillatory patterns in single pancreatic acinar cells of mouse.

Modulation of the agonist-specific cytosolic Ca2+ oscillatory pattern by thimerosal has been investigated in single pancreatic acinar cells using patch-clamp perforated whole-cell recording to measure the calcium-dependent chloride current (I(C1)(Ca2+)). 1 microM thimerosal, which fails to evoke Ca2+ oscillation alone, clearly changed the pattern of Ca2+ oscillation from pulsatile spikes (evoked by low concentrations of activators) to sinusoidal or transient oscillations. The mimetic action of thimerosal was independent of extracellular Ca2+, was blocked by extracellular application of dithiothreitol or 10 mM caffeine, as well as by internal perfusion with heparin; but was unaffected by ruthenium red. We conclude that thimerosal modulates the agonist-specific cytosolic Ca2+ oscillatory patterns mediated by sensitizing the InsP3-induced Ca2+ release.

Acetylcholine↗
PubMed1996

Role of extracellular Ca2+ in acetylcholine-induced repetitive Ca2+ release in submandibular gland acinar cells of the rat.

Acetylcholine (ACh) caused repetitive transient Cl- currents activated by intracellular Ca2+ in single rat submandibular grand acinar cells. As the concentration of ACh increased the amplitude and the frequency of the transient Cl- currents increased. These responses occurred also in the absence of extracellular Ca2+ but disappeared after several minutes. Repetitive transient Cl- currents were restored by readmission of Ca2+ to the extracellular solution. The higher the concentration of extracellular Ca2+ readmitted, the larger the amplitude of the transient Cl- currents. Ca2+ entry through a store-coupled pathway was detected by application of Ca2+ to the extracellular solution during a brief cessation of stimulation with ACh. In these experiments too, the higher the concentration of Ca2+, the larger the transient Cl- currents activated by Ca2+ released from the stores. The time course of decrease in total charge movements of repetitive transient responses to ACh with removal of extracellular Ca2+ depended on a decrease in charge movements of each transient event rather than a decrease in frequency of the repetitive events. The decrease of charge movements of each transient event was due to a decrease in its amplitude rather than its duration. The results suggest that in this cell type and amplitude-modulated mechanism is involved in repetitive Ca2+ release and that Ca2+ entry is essential to maintain the repetitive release of Ca2+. The results further suggest that the magnitude of Ca2+ entry determines the number of unitary stores filled with Ca2+ which can synchronously respond to ACh.

Acetylcholine↗
PubMed1996

Excitatory and inhibitory actions of norepinephrine on the Ba2+ current through L-type Ca2+ channels of smooth muscle cells of guinea-pig vas deferens.

The effect of norepinephrine (NE) was examined on the whole-cell Ba2+ current through L-type Ca2+ channels of freshly isolated smooth muscle cells of guinea-pig vas deferens. The magnitude of maximum Ba2+ current [1Ba(max)] varied in different cells, although the capacitance of the cell membrane was similar (approximately 50 pF). Application of dbcAMP augmented 1Ba(max) by 37%, which was canceled by Rp-cAMPs, while PMA decreased the current by 32%, which was canceled by staurosporine. NE increased 1Ba(max) of the cells which originally showed relatively small 1Ba(max), and decreased the current of the cells which showed larger 1Ba(max). In the presence of phentolamine, NE increased 1Ba(max), and this effect was remarkable in cells showed smaller 1Ba(max). In the presence of propranolol, NE decreased 1Ba(max). The excitatory beta-adrenoceptor activation was canceled by Rp-cAMPs, and the inhibitory alpha-adrenoceptor effect was canceled by staurosporine. It is suggested that NE shows dual (excitatory and inhibitory) actions on the L-type Ca2+ channels of smooth muscle of guinea-pig vas deferens. The excitatory beta-adrenoceptor action mediated through cAMP/PKA is predominant in cells with lower density of the Ca2+ channels, while inhibitory alpha-adrenoceptor action mediated through PKC is predominant in cells with higher channel density.

Adrenergic Agonists↗
PubMed1996

Cloning of mouse integrin alphaV cDNA and role of the alphaV-related matrix receptors in metanephric development.

Metanephrogenesis has been a long-standing model to study cell-matrix interactions. A number of adhesion molecules, including matrix receptors (i.e., integrins), are believed to be involved in such interactions. The integrins contain alpha and beta s ubunits and are present in various tissues in different heterodimeric forms. In this study, one of the members of the integrin superfamily, alphaV, was characterized, and its relevance in murine nephrogenesis was investigated. Mouse embryonic renal cDNA libraries were prepared and screened for alphaV, and multiple clones were isolated and sequenced. The deduced amino acid sequence of the alpha-v cDNA clones and hydropathic analysis revealed that it has a typical signal sequence and extracellular, transmembrane, and cytoplasmic domains, with multiple Ca2+ binding sites. No A(U)nA mRNA instability motifs were present. Conformational analysis revealed no rigid long-range-ordered structure in murine alphaV. The alphaV was expressed in the embryonic kidney at day 13 of the gestation, with a transcript size of approximately 7 kb. Its expression increased progressively during the later gestational stages and in the neonatal period. It was distributed in the epithelial elements of developing nephrons and was absent in the uninduced mesenchyme. In mature metanephroi, the expression was relatively high in the glomeruli and blood vessels, as compared to the tubules. Various heterodimeric associations of alphaV, i.e., with beta1, beta3, beta5, and beta6, were observed in metanephric tissues. Inclusion of alphaV-antisense-oligodeoxynucleotide or -antibody in metanephric culture induced dysmorphogenesis of the kidney with reduced population of the nephrons, disorganization of the ureteric bud branches, and reduction of mRNA and protein expressions of alphaV. The expressions of integrin beta3, beta5, and beta6 were unaltered. These findings suggest that the integrin alphaV is developmentally regulated, has a distinct spatio-temporal expression, and is relevant in the mammalian organogenesis.

Amino Acid Sequence↗
PubMed1996

The critical role of intercellular adhesion molecule-1 in Masugi nephritis in rats.

Intercellular adhesion molecule-1 (ICAM-1, CD54), an adhesion molecule of the immunoglobulin superfamily, is an endothelial cell surface ligand for such leukocyte integrins as lymphocyte-function-associated molecule 1 (LFA-1, CD11a/CD18), Mac-1 (CD11b/CD18) and CD43. These molecules mediate adhesive interactions between leukocytes and endothelial cells and are critically involved in infiltration of leukocytes into inflammatory lesions. We examined the expression of ICAM-1 in renal tissues of Masugi nephritis rats and directly examined the role of ICAM-1 by administration of neutralizing monoclonal antibodies (MAbs) to rat ICAM-1, LFA-1 alpha-subunit (LFA-1 alpha), beta-subunit (LFA-1 beta) and Mac-1 alpha-subunit (Mac-1 alpha). Within 3 h after injection of nephrotoxic serum, increased expression of ICAM-1 was detected in the glomeruli by in situ hybridization and an immunofluorescence study. Proteinuria was significantly suppressed by the MAbs against ICAM-1, Mac-1 alpha and LFA-1 beta. Neutrophil infiltration into the glomeruli was significantly prevented by injection of the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta. These results indicate that both ICAM-1/LFA-1 and ICAM-1/Mac-1 pathways are involved in neutrophil infiltration into the glomeruli. On the other hand, monocytic infiltration was prevented by the MAbs against ICAM-1, LFA-1 alpha and LFA-1 beta but not by anti-Mac-1 alpha MAb. Due to these results, ICAM-1 is considered to be a critical molecule involved in the pathogenesis of the leukocyte infiltration into the glomeruli in the heterologous phase of Masugi nephritis. Anti-ICAM-1 antibody may be beneficial in the treatment of leukocyte-mediated glomerular diseases.

Animals↗
PubMed1995

Distribution of extracellular matrix receptors in various forms of glomerulonephritis.

Integrins are heterodimeric transmembrane receptor glycoproteins consisting of alpha and beta subunits that mediate adhesion and interactions between cells and extracellular matrix. Such interactions may be perturbed in various pathologic states, resulting in the altered phenotypic expressions of the integrins in affected tissues. To ascertain the alterations in integrins in various renal diseases, their distribution was investigated in different forms of glomerulonephritis by indirect immunofluorescence and immunoelectron microscopy using specific antibodies directed against beta 1 integrins and integrin alpha v beta 3 (vitronectin receptor). In addition, the distribution of certain extracellular matrix components (ie, fibronectin, vitronectin, and type IV collagen) was examined. Integrin beta 1 and alpha v beta 3 were highly expressed in proliferating mesangial cells in immunoglobulin A nephropathy, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. Their putative ligands (ie, fibronectin, vitronectin, and type IV collagen) also were increased in the expanded mesangial regions. In immunoglobulin A nephropathy, integrin beta 1 and alpha v beta 3 were seen by immunoelectron microscopy to be localized to the mesangial cell membranes in close proximity to the immune complex deposits; however, fibronectin and vitronectin immunoreactivities were observed in the mesangial immune complex deposits. Similarly, vitronectin also was detected in the immune complex deposits of other forms of proliferative nephritis, ie, membranoproliferative glomerulonephritis type I and diffuse proliferative lupus nephritis. In diffuse proliferative lupus nephritis, the cellular crescents displayed immunoreactivity toward integrin alpha v beta 3 and vitronectin. In nonimmune complex glomerular disease associated with nephrotic syndrome (ie, minimal change nephrotic syndrome), integrin alpha 3 beta 1, which normally has a linear capillary distribution, was decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Collagen↗
PubMed1995

Ca2+ entry through the store-mediated pathway directly activates only the K+ current but the subsequent Ca2+ release from the store activates both K+ and Cl- currents in submandibular gland acinar cells of the rat.

The store-mediated Ca2+ entry was detected in single and cluster of rat submandibular acinar cells by measuring the Ca2+ activated ionic membrane currents. In the cells where intracellular Ca2+ was partly depleted by stimulation with submaximal concentration of acetylcholine (ACh) under a Ca2(+)-free extracellular condition, an employment of external Ca2+ in the absence of ACh caused a sustained increase of the K+ current without affecting the Cl- current. A renewed ACh challenge without external Ca2+ caused repetitive spikes of both K+ and Cl- currents due to the Ca2+ release. SK & F 96365 inhibited the generation of the sustained K+ current and refilling of the Ca2+ store following the Ca2+ readmission. It is suggested that the Ca2+ enters the cell through the store-mediated pathway new the K+ channels and is taken up by the store. Thus, only Ca2+ released from the store can activate both the K+ and Cl- currents.

Acetylcholine↗