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Silver J, Martinez-Rubio MI, Ireland TG, Fern GR, Withnall R. The Effect of Particle Morphology and Crystallite Size on the Upconversion Luminescence Properties of Erbium and Ytterbium Co-doped Yttrium Oxide Phosphors. J Phys Chem B 2001. [DOI: 10.1021/jp002778c] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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52
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Lu X, Silver J. Transmission of replication-defective Sindbis helper vectors encoding capsid and envelope proteins. J Virol Methods 2001; 91:59-65. [PMID: 11164486 DOI: 10.1016/s0166-0934(00)00247-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A green fluorescent protein (gfp)-encoding derivative of the replication-defective Sindbis helper vector DHBB was constructed in order to study the rate of packaging of the helper vector. The results show that despite lacking a 'packaging sequence', this vector is co-packaged about 1/300th the rate of packaging of single RNAs containing a packaging sequence. This helps explain the frequent observation of recombinant, replication-competent viruses when using first generation Sindbis packaging systems. Because of their sensitivity, gfp-encoding reporters like the one described here will be useful for measuring transfer of helper RNAs in improved alpha virus packaging systems.
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53
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Olchovsky D, Hobbs M, Pras E, Shimon I, Silver J, Irmin L, Friedman E. Familial Isolated Primary Hyperparathyroidism in a Large Georgian-Jewish Kindred: Genetic Studies. ACTA ACUST UNITED AC 2001. [DOI: 10.1515/ijdhd.2001.2.2.91] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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54
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Hegde VR, Silver J, Patel M, Gullo VP, Yarborough R, Huang E, Das PR, Puar MS, DiDomenico BJ, Loebenberg D. Novel fungal metabolites as cell wall active antifungals: fermentation, isolation, physico-chemical properties, structure and biological activity. J Antibiot (Tokyo) 2001; 54:74-83. [PMID: 11269717 DOI: 10.7164/antibiotics.54.74] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two novel antifungal compounds, 1 (SCH 466457), and 2 (SCH 466456), active in a "cell wall" assay, were isolated from the fermentation broth of an unidentified fungus. The active compounds were separated from the broth filtrate by adsorption on a macroreticular resin and were purified on reverse phase HPLC. Detailed mass spectrometric and NMR experiments and degradative studies helped in elucidating the structures of these compounds. The compounds were identified to be peptides containing amino acids such as alanine, aminoisobutyric acid, proline, leucine, valine, glycine and a previously identified beta-keto acid, 2-methyl 3-oxotetradecanoic acid. (5) Both compounds were active against Candida, dermatophytes and Aspergillus (Geometric Mean MIC's, 8.9, 20 and 16 microg/ml, and 64, 128 and 23 microg/ml, respectively for 1 and 2).
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55
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Brouns MR, Matheson SF, Hu KQ, Delalle I, Caviness VS, Silver J, Bronson RT, Settleman J. The adhesion signaling molecule p190 RhoGAP is required for morphogenetic processes in neural development. Development 2000; 127:4891-903. [PMID: 11044403 DOI: 10.1242/dev.127.22.4891] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Rho GTPases direct actin rearrangements in response to a variety of extracellular signals. P190 RhoGAP (GTPase activating protein) is a potent Rho regulator that mediates integrin-dependent adhesion signaling in cultured cells. We have determined that p190 RhoGAP is specifically expressed at high levels throughout the developing nervous system. Mice lacking functional p190 RhoGAP exhibit several defects in neural development that are reminiscent of those described in mice lacking certain mediators of neural cell adhesion. The defects reflect aberrant tissue morphogenesis and include abnormalities in forebrain hemisphere fusion, ventricle shape, optic cup formation, neural tube closure, and layering of the cerebral cortex. In cells of the neural tube floor plate of p190 RhoGAP mutant mice, polymerized actin accumulates excessively, suggesting a role for p190 RhoGAP in the regulation of +Rho-mediated actin assembly within the neuroepithelium. Significantly, several of the observed tissue fusion defects seen in the mutant mice are also found in mice lacking MARCKS, the major substrate of protein kinase C (PKC), and we have found that p190 RhoGAP is also a PKC substrate in vivo. Upon either direct activation of PKC or in response to integrin engagement, p190 RhoGAP is rapidly translocated to regions of membrane ruffling, where it colocalizes with polymerized actin. Together, these results suggest that upon activation of neural adhesion molecules, the action of PKC and p190 RhoGAP leads to a modulation of Rho GTPase activity to direct several actin-dependent morphogenetic processes required for normal neural development.
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56
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Haviv YS, Silver J. Late onset oncogenic osteomalacia-associated with neurofibromatosis type II. Clin Nephrol 2000; 54:429-30. [PMID: 11105809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
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57
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Lu X, Silver J. Ecotropic murine leukemia virus receptor is physically associated with caveolin and membrane rafts. Virology 2000; 276:251-8. [PMID: 11040117 DOI: 10.1006/viro.2000.0555] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We used a Sindbis virus expression system to stably express a chimeric ecotropic murine leukemia virus (MLV) receptor gene, CAT1, fused to green fluorescent protein (gfp) in BHK cells. The chimeric gene was expressed on the cell surface and functioned as an MLV receptor. Using gfp as an epitope tag, we found that CAT1 cross-immunoprecipitated with caveolin, a cellular protein associated non-clathrin-coated endocytic vesicles. Biochemical studies showed that CAT1 copurified with caveolin in a detergent-insoluble membrane fraction that forms cholesterol-rich "rafts" on the cell surface. Disruption of rafts by methyl-beta-cyclodextrin, a drug that extracts cholesterol, reduced susceptibility to MLV without decreasing surface CAT1. The results indicate that association of the MLV receptor with cholesterol-rich rafts is important for an early step in virus infection.
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58
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Devi G, Silver J. Approaches to memory loss in neuropsychiatric disorders. SEMINARS IN CLINICAL NEUROPSYCHIATRY 2000; 5:259-65. [PMID: 11291022 DOI: 10.1053/scnp.2000.16528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Many neuropsychiatric disorders affect memory. Brain regions important in the neuroanatomic substrate of memory include the hippocampus, and sections of the frontal, temporal, and parietal cortices and the thalamus. Acetylcholine and many other neurotransmitters and neuromodulators including dopamine, glutamate, GABA, the catecholamines, and estrogen modulate cognitive function. Treatment approaches to memory loss typically use Alzheimer's dementia as the template, and are discussed in this report.
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59
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60
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Silver J, Winland-Brown JE. Power asymmetry and patient autonomy. Am J Crit Care 2000; 9:360-1. [PMID: 10976360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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61
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62
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Abstract
Secondary hyperparathyroidism is a frequent complication of chronic renal failure (CRF) and a major factor in the pathogenesis of renal osteodystrophy. A high serum phosphate, decreased levels of serum 1,25(OH)2D3 and the subsequently low serum calcium are the major metabolic abnormalities in CRF, which lead to the secondary hyperparathyroidism. At the level of parathyroid hormone (PTH) secretion there is insensitivity to the ambient serum calcium. PTH mRNA levels are increased by a post-transcriptional mechanism that involves the binding of PT cytosolic proteins to the PTH mRNA 3'-untranslated region (UTR). In a dietary model of secondary hyperparathyroidism due to hypocalcemia there is increased binding of parathyroid proteins to the 3'-UTR and decreased degradation as determined by an in vitro degradation assay. Changes in serum phosphate also dramatically regulate PTH mRNA stability. There is also regulation at the level of PT cell proliferation. PT cell proliferation is increased by experimental hypocalcemia or hyperphosphatemia and decreased by hypophosphatemia and administered 1,25(OH)2D3. The understanding of the molecular mechanisms involved in the genesis of secondary hyperparathyroidism will allow the design of new effective strategies in the management of this troubling condition.
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63
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Silver J, Marsh PJ, Symons MC, Svistunenko DA, Frampton CS, Fern GR. Crystal structure of bis(4-methylimidazole)tetraphenylporphyrinatoiron(III) chloride and related compounds. Correlation of ground state with Fe-N bond lengths. Inorg Chem 2000; 39:2874-81. [PMID: 11232827 DOI: 10.1021/ic990848s] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The crystal structure of the title compound is presented and shown to be one of a class of low-spin iron porphyrin complexes having a ground-state electronic configuration of (dxy)2(dxz)2(dyz)1. If their Fe-N bond lengths (average N-porphyrin plotted against average N-axial) are considered, this class of low-spin iron(III) porphyrins of general formula [Fe(III)Por(L)2]+X- and of 2B ground state is shown to be distinctly different crystallographically from a similar class of compounds with the same general formula but with a 2E or a (dxy)2(dxz,dyz)3 ground state. A third group of compounds with the same general formula have a (dxz,dyz)4(d)1 ground state and again are in a different region of the plot. Compounds showing intermediate properties can be forecast from the simple relationship presented in this work. The electron paramagenetic resonance data are shown to be dependent on the ground state, and those of configuration (dxy)2(dxz,dyz)3 and the 2B ground state obey a correlation previously suggested in the literature.
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64
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Silver J. Public policy update. An amfAR report. AIDS Patient Care STDS 2000; 14:333-4. [PMID: 10897506 DOI: 10.1089/10872910050046368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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65
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Silver J. Aspects of failed back syndrome: role of litigation. Spinal Cord 2000; 38:386; author reply 387. [PMID: 10991613 DOI: 10.1038/sj.sc.3101017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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66
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Gulwani-Akolkar B, Akolkar PN, Lin XY, Heresbach D, Manji R, Katz S, Yang SY, Silver J. HLA class II alleles associated with susceptibility and resistance to Crohn's disease in the Jewish population. Inflamm Bowel Dis 2000; 6:71-6. [PMID: 10833064 DOI: 10.1097/00054725-200005000-00001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Previous studies have suggested that susceptibility to Crohn's disease (CD) is associated with the histocompatibility complex (HLA) class II alleles DR1, DQ5, and DR13 in the Caucasian population, DR7 in the French and German populations, and DR4 and DQ4 in the Japanese population. However, little is known about the relationship between HLA class II alleles and CD in the Jewish population since these previous studies included few Jewish individuals. In order to determine whether the HLA associations observed with predominantly non-Jewish populations were also present in the Jewish CD population and whether there were any HLA class II alleles uniquely associated with CD in the Jewish population, 132 CD patients, of which 82 were Ashkenazi Jewish, were HLA-typed using serologic and DNA methods. Ethnically matched controls were similarly typed. No association with DR1 or DR13 was observed in the Jewish CD population although an association with DR13 (OR [odds ratio] = 5.3, p = 0.02) was observed in the non-Jewish CD population. However, an association with DR15 (OR = 2.7, p = 0.03), which is normally associated with ulcerative colitis, was observed in the Jewish, but not non-Jewish, CD group. In addition, a strong negative association was observed with DR3, which was especially striking in the Jewish population (OR = 0.35, p = 0.025); similar negative associations with DR3 have been observed by others using non-Jewish populations. Furthermore, a significant negative association with DR7 (OR = 0.45, p = 0.04) was observed in the Jewish, but not non-Jewish, population. Consistent with this was the negative association with DQ2 (OR = 0.38, p = 0.005), which is in strong linkage disequilibrium with both DR3 and DR7, in the Jewish, but not non-Jewish, population. These studies support previous suggestions that susceptibility to CD in Jewish and non-Jewish populations is determined by distinct genes and provide further support to the hypothesis that a gene on the DR3 haplotype may protect against CD. Furthermore, protection is conferred by the same or another gene found on Jewish, but not non-Jewish, DR7 haplotypes.
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67
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Sela-Brown A, Silver J, Brewer G, Naveh-Many T. Identification of AUF1 as a parathyroid hormone mRNA 3'-untranslated region-binding protein that determines parathyroid hormone mRNA stability. J Biol Chem 2000; 275:7424-9. [PMID: 10702317 DOI: 10.1074/jbc.275.10.7424] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Parathyroid hormone (PTH) mRNA levels are post-transcriptionally increased by hypocalcemia and decreased by hypophosphatemia, and this is mediated by cytosolic proteins binding to the PTH mRNA 3'-untranslated region (UTR). The same proteins are also present in other tissues, such as brain, but only in the parathyroid is their binding regulated by calcium and phosphate. The function of the PTH mRNA 3'-UTR-binding proteins was studied using an in vitro degradation assay. Competition for the parathyroid-binding proteins by excess unlabeled 3'-UTR destabilized the full-length PTH transcript in this assay, indicating that these proteins protect the RNA from RNase activity. The PTH RNA 3'-UTR-binding proteins were purified by RNA affinity chromatography of rat brain S-100 extracts. The eluate from the column was enriched in PTH RNA 3'-UTR binding activity. Addition of eluate to the in vitro degradation assay with parathyroid protein extracts stabilized the PTH transcript. A major band from the eluate at 50 kDa was sequenced and was identical to AU-rich binding protein (AUF1). Recombinant AUF1 bound the full-length PTH mRNA and the 3'-UTR. Added recombinant AUF1 also stabilized the PTH transcript in the in vitro degradation assay. Our results show that AUF1 is a protein that binds to the PTH mRNA 3'-UTR and stabilizes the PTH transcript.
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68
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Epstein E, Sela-Brown A, Ringel I, Kilav R, King SM, Benashski SE, Yisraeli JK, Silver J, Naveh-Many T. Dynein light chain binding to a 3'-untranslated sequence mediates parathyroid hormone mRNA association with microtubules. J Clin Invest 2000; 105:505-12. [PMID: 10683380 PMCID: PMC289163 DOI: 10.1172/jci8557] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The 3'-untranslated region (UTR) of mRNAs binds proteins that determine mRNA stability and localization. The 3'-UTR of parathyroid hormone (PTH) mRNA specifically binds cytoplasmic proteins. We screened an expression library for proteins that bind the PTH mRNA 3'-UTR, and the sequence of 1 clone was identical to that of the dynein light chain LC8, a component of the dynein complexes that translocate cytoplasmic components along microtubules. Recombinant LC8 binds PTH mRNA 3'-UTR, as shown by RNA electrophoretic mobility shift assay. We showed that PTH mRNA colocalizes with microtubules in the parathyroid gland, as well as with a purified microtubule preparation from calf brain, and that this association was mediated by LC8. To our knowledge, this is the first report of a dynein complex protein binding an mRNA. The dynein complex may be the motor that is responsible for transporting mRNAs to specific locations in the cytoplasm and for the consequent is asymmetric distribution of translated proteins in the cell.
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69
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Kazachkov Y, Long D, Wang C, Silver J. Changes in a murine leukemia virus (MLV) receptor encoded by an alphavirus vector during passage in cells expressing the MLV envelope. Virology 2000; 267:124-32. [PMID: 10648189 DOI: 10.1006/viro.1999.0114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We constructed alphavirus vectors encoding the ecotropic murine leukemia virus (MLV) receptor mCAT1. Cells electroporated with these vector RNAs expressed mCAT1 protein and fused with cells that expressed a fusogenic form of the MLV envelope on the cell surface. Electroporated cells also released submicron particles that were infectious in envelope-expressing cells. Infection resulted in giant syncytia that could be enumerated by plaque assay. Cell-free supernatants could be serially passaged and contained up to 10(4) infectious units/ml. To determine whether repeated passage would select for functional variants of the receptor, we analyzed mCAT1 amplified by RT-PCR after 12 serial passages. Several amino acid substitutions were identified that encoded functional receptor variants. In independent experiments, variants containing an isoleucine or a leucine instead of a phenylalanine at position 224 in the third extracellular domain of the receptor arose spontaneously and outgrew the parental vector, indicating that mutations at this site are highly selected in this system. This region of the receptor has previously been implicated in the envelope-receptor interaction. This alphavirus vector system provides a novel method for generating and selecting functional variants of viral receptors
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70
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Smalley JW, Birss AJ, Silver J. The periodontal pathogen Porphyromonas gingivalis harnesses the chemistry of the mu-oxo bishaem of iron protoporphyrin IX to protect against hydrogen peroxide. FEMS Microbiol Lett 2000; 183:159-64. [PMID: 10650220 DOI: 10.1111/j.1574-6968.2000.tb08951.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The major haem component in the black pigment of Porphyromonas gingivalis is the mu-oxo bishaem of iron protoporphyrin IX and formation and cell-surface binding of this haem species is proposed as an extracellular buffer against reactive oxidants [Smalley, J.W. et al. (1998) Biochem. J. 331, 681-685]. P. gingivalis cells grown in the presence of the mu-oxo bishaem were protected against H(2)O(2) compared to control cells grown without it. When added to the growth medium, soluble mu-oxo bishaem inactivated H(2)O(2) and supported cell growth. Cells carrying a surface layer of mu-oxo bishaem were less susceptible to peroxidation by H(2)O(2). Cell-surface haems were slowly destroyed during reaction with H(2)O(2). Binding of mu-oxo bishaem by P. gingivalis may aid survival during neutrophil attack through inactivation of hydrogen peroxide.
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71
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Silver J. Solving the healthcare crisis: a sociophilosophical approach. JONA'S HEALTHCARE LAW, ETHICS AND REGULATION 1999; 1:15-6. [PMID: 10824007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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72
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Silver J, Yalcindag C, Sela-Brown A, Kilav R, Naveh-Many T. Regulation of the parathyroid hormone gene by vitamin D, calcium and phosphate. KIDNEY INTERNATIONAL. SUPPLEMENT 1999; 73:S2-7. [PMID: 10633456 DOI: 10.1046/j.1523-1755.1999.07310.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Secondary hyperparathyroidism is a frequent complication of chronic renal failure resulting in severe bone disease. Secondary hyperparathyroidism is composed of increased in parathyroid hormone (PTH) synthesis and secretion due to an increase in PTH gene expression and parathyroid cell proliferation. PTH gene expression is regulated by calcium, phosphate and 1,25-dihydroxy vitamin D (1,25(OH)2D). 1,25(OH)2D3 injected to rats leads to a dramatic decrease in PTH gene transcription without any increase in serum calcium. Hypocalcemia leads to a large increase in PTH mRNA levels which is post-transcriptional. Hypophosphatemia leads to a marked decrease in PTH gene expression that is also post-transcriptional. The mechanisms of the post-transcriptional effects of calcium and phosphate on the PTH gene have shown to be due to changes in protein-RNA interactions at the PTH mRNA 3'-UTR. Hypocalcemia leads to increased binding of parathyroid cytosolic proteins to the PTH mRNA 3'-UTR and hypophosphatemia to decreased binding of these proteins to the PTH mRNA 3'-UTR. The binding of the parathyroid proteins stabilizes the PTH RNA in an in vitro degradation assay. In rats with experimental uremia due to 5/6 nephrectomy, there is an increase in PTH mRNA levels due to a decrease in degradation of the PTH RNA as determined by this assay. The characterization of the parathyroid cytosolic proteins that interact with the PTH mRNA 3'-UTR may lead to a clearer understanding of how changes in serum calcium and phosphate result in secondary hyperparathyroidism.
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73
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Yalcindag C, Silver J, Naveh-Many T. Mechanism of increased parathyroid hormone mRNA in experimental uremia: roles of protein RNA binding and RNA degradation. J Am Soc Nephrol 1999; 10:2562-8. [PMID: 10589695 DOI: 10.1681/asn.v10122562] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Patients with chronic renal failure develop secondary hyperparathyroidism with increased synthesis and secretion of parathyroid hormone (PTH) resulting in severe skeletal complications. In rats with secondary hyperparathyroidism due to 5/6 nephrectomy, there are increased PTH mRNA levels, and this mechanism was studied. Parathyroid glands were microdissected from control and 5/6 nephrectomy rats and analyzed for PTH mRNA and control genes, and the nuclei were used for nuclear run-on experiments. The cytosolic proteins of the parathyroids were used to study PTH mRNA protein binding by ultraviolet cross-linking and the degradation of the PTH transcript in vitro. Nuclear run-ons showed that the increase in PTH mRNA levels was posttranscriptional. Protein binding to the PTH mRNA 3'-UTR determines PTH mRNA stability and levels. Parathyroid proteins from uremic rats bound PTH mRNA similar to control rats by ultraviolet cross-linking. To determine the effect of uremia on PTH mRNA stability, an in vitro RNA degradation assay was performed with parathyroid proteins from uremic rats. When parathyroid proteins from control rats were incubated with PTH mRNA, there was transcript degradation already at 30 min, reaching 50% at 60 min and 90% at 180 min. With uremic parathyroid proteins, the PTH mRNA was not degraded at all at 120 min and was moderately decreased at 180 min. This decrease in degradation by uremic parathyroid proteins suggests a decrease in parathyroid cytosolic endonuclease activity in uremia resulting in a more stable PTH transcript. The increased PTH mRNA levels would translate into increased PTH synthesis and serum PTH levels, which would lead to metabolic bone disease in many patients with chronic renal failure.
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MESH Headings
- 3' Untranslated Regions
- 5' Untranslated Regions
- Animals
- Cytosol/metabolism
- Hyperparathyroidism, Secondary/etiology
- Hyperparathyroidism, Secondary/genetics
- Hyperparathyroidism, Secondary/metabolism
- Kidney Failure, Chronic/complications
- Kidney Failure, Chronic/genetics
- Kidney Failure, Chronic/metabolism
- Male
- Models, Biological
- Nephrectomy
- Parathyroid Glands/metabolism
- Parathyroid Hormone/biosynthesis
- Parathyroid Hormone/genetics
- Protein Binding
- RNA Processing, Post-Transcriptional
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Uremia/genetics
- Uremia/metabolism
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74
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Silver J, Mi Z, Takamoto K, Bungay P, Brown J, Powell A. Controlled Formation of Low-Volume Liquid Pillars between Plates with a Lattice of Wetting Patches by Use of a Second Immiscible Fluid. J Colloid Interface Sci 1999; 219:81-89. [PMID: 10527574 DOI: 10.1006/jcis.1999.6422] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe a method for forming an array of microdroplets between two plates, at least one of which is patterned with a lattice of wetting patches, using a second immiscible fluid to control droplet formation. The method may be useful for performing multiple, small-volume biochemical reactions in parallel. We analyze the forces responsible for droplet formation, describe results of a computer simulation using Surface Evolver, and derive an analytic criterion for droplet formation in terms of the contact angles of the droplet:second fluid interface on the wetting patches and surrounding surface, the diameter of the wetting patches, the distance between wetting patches, and the distance between the plates. Copyright 1999 Academic Press.
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75
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Fitch MT, Doller C, Combs CK, Landreth GE, Silver J. Cellular and molecular mechanisms of glial scarring and progressive cavitation: in vivo and in vitro analysis of inflammation-induced secondary injury after CNS trauma. J Neurosci 1999; 19:8182-98. [PMID: 10493720 PMCID: PMC6783021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Post-traumatic cystic cavitation, in which the size and severity of a CNS injury progress from a small area of direct trauma to a greatly enlarged secondary injury surrounded by glial scar tissue, is a poorly understood complication of damage to the brain and spinal cord. Using minimally invasive techniques to avoid primary physical injury, this study demonstrates in vivo that inflammatory processes alone initiate a cascade of secondary tissue damage, progressive cavitation, and glial scarring in the CNS. An in vitro model allowed us to test the hypothesis that specific molecules that stimulate macrophage inflammatory activation are an important step in initiating secondary neuropathology. Time-lapse video analyses of inflammation-induced cavitation in our in vitro model revealed that this process occurs primarily via a previously undescribed cellular mechanism involving dramatic astrocyte morphological changes and rapid migration. The physical process of cavitation leads to astrocyte abandonment of neuronal processes, neurite stretching, and secondary injury. The macrophage mannose receptor and the complement receptor type 3 beta2-integrin are implicated in the cascade that induces cavity and scar formation. We also demonstrate that anti-inflammatory agents modulating transcription via the nuclear hormone receptor peroxisome proliferator-activated receptor-gamma may be therapeutic in preventing progressive cavitation by limiting inflammation and subsequent secondary damage after CNS injury.
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