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Chattopadhyay N, Ye C, Singh DP, Kifor O, Vassilev PM, Shinohara T, Chylack LT, Brown EM. Expression of extracellular calcium-sensing receptor by human lens epithelial cells. Biochem Biophys Res Commun 1997; 233:801-5. [PMID: 9168937 DOI: 10.1006/bbrc.1997.6553] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The extracellular calcium-sensing receptor (CaR) confers the capacity to sense small changes in the extracellular Ca2+ concentration (Ca2+o) not only upon cells involved in maintaining systemic Ca2+ homeostasis but also upon those not directly involved in this process. Since high Ca2+o is known to affect various physiological processes in lens epithelium both in health and in disease states (e.g., the formation of cataracts in hypocalcemic states), we investigated the expression and function of the CaR in these cells. By RT-PCR and immunocytochemistry the CaR is expressed in human lens epithelial cells in culture. In addition, the open state probability of a Ca(2+)-activated potassium (K+) channel with a conductance of 82 +/- 3 pS is significantly increased by elevating Ca2+o to 3.0 mM or by application of 100 microM neomycin, both effective CaR agonists. Therefore, our data suggest that human lens-epithelial cells express the CaR, which may be functionally linked to Ca(2+)-activated K+ channels and, perhaps, to other ion channels involved in ionic homeostasis in the lens.
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Vassilev PM, Ho-Pao CL, Kanazirska MP, Ye C, Hong K, Seidman CE, Seidman JG, Brown EM. Cao-sensing receptor (CaR)-mediated activation of K+ channels is blunted in CaR gene-deficient mouse neurons. Neuroreport 1997; 8:1411-6. [PMID: 9172145 DOI: 10.1097/00001756-199704140-00018] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The extracellular Ca2+ (Cao)-sensing receptor (CaR) is expressed in hippocampus and other brain regions, suggesting that it could mediate some of the well recognized but poorly understood direct actions of Cao on neuronal function. This study presents evidence that the CaR is functionally coupled to Ca(2+)-activated K+ channels. The effects of CaR agonists on these channels in neurons from wild type (WT) and CaR-deficient (CaR -/-) mice were compared. Neomycin (100 mM) and elevation of Cao from 0.5 to 3 mM significantly increased the probability of channel opening (Po) in neurons from WT but not in those from CaR -/- mice. Thus the CaR activates neuronal K+ channels and could potentially inhibit neuronal excitability and neurotransmission via membrane repolarization.
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Hu JZ, Zhou J, Yang B, Li L, Qiu J, Ye C, Solum MS, Wind RA, Pugmire RJ, Grant DM. Dynamic nuclear polarization of nitrogen-15 in benzamide. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1997; 8:129-137. [PMID: 9203286 DOI: 10.1016/s0926-2040(96)01263-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A 15N dynamic nuclear polarization (DNP) experiment is reported in which a 15N DNP enhancement factor of approximately 2.6 x 10(2) is obtained on free radical doped samples of 99% 15N labeled benzamide. The free radicals BDPA (1:1 complex of alpha, gamma-bisdiphenylene-beta-phenylallyl with benzene) and DPPH (2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl) are used as dopants and the spin relaxation effects of adding these dopants are studied by means of changes in proton and nitrogen T1 values of the samples. The combination in solids of a very low natural abundance, 0.37%, a small gyromagnetic ratio, and a long spin-lattice relaxation time for 15N nuclei create severe sensitivity problems that, in large part, are ameliorated by the signal enhancement observed in the 15N DNP experiment on samples containing free electrons.
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Wang PY, Ye C, Pang YZ, Su JY, Tang CS. [Changes of calcium transport in rat liver nuclei during sepsis]. SHENG LI XUE BAO : [ACTA PHYSIOLOGICA SINICA] 1997; 49:191-6. [PMID: 9812856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Calcium transport changes in rat liver nuclei were observed on the model of early sepsis (9 h after operation of cecal ligation and puncture). Calcium content in hepatocytes and nuclei were significantly increased by 20% and 36% respectively (P < 0.05) during sepsis. The activity of Ca(2+)-ATPase in hepatocytic nuclei was increased by 94% (P < 0.01) and 45Ca2+ transport accelerated by 32% (P < 0.01). There was a positive correlation between nuclear 45Ca2+ transport and nuclear Ca(2+)-ATPase activity (r = 0.914, P < 0.01). Calmodulin stimulated the activity of nuclear Ca(2+)-ATPase and 45Ca2+ transport; while calmodulin inhibitor trifluoperazine exerted an opposite effect. The above results suggest that liver nuclear calcium transport is strengthened during early sepsis as a result of changes of Ca(2+)-ATPase activity.
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Ye C, Ho-Pao CL, Kanazirska M, Quinn S, Rogers K, Seidman CE, Seidman JG, Brown EM, Vassilev PM. Amyloid-beta proteins activate Ca(2+)-permeable channels through calcium-sensing receptors. J Neurosci Res 1997; 47:547-54. [PMID: 9067864 DOI: 10.1002/(sici)1097-4547(19970301)47:5<547::aid-jnr10>3.0.co;2-v] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The amyloid-beta peptides (A beta) are produced in excess in Alzheimer's disease (AD) and may contribute to neuronal dysfunction and degeneration. This study provides strong evidence for a novel cellular target for the actions of A beta, the phospholipase C-coupled, extracellular Ca(2+)-sensing receptor (CaR). We demonstrate that A beta(s) produce a CaR-mediated activation of a Ca(2+)-permeable, nonselective cation channel (NCC), probably via elevation in cytosolic Ca2+ (Cai), in cultured hippocampal pyramidal neurons from normal rats and from wild type mice but not those from mice with targeted disruption of the CaR gene (CaR -/-). A beta(s) also activate NCC in CaR-transfected but not in nontransfected human embryonic kidney (HEK293) cells. Thus aggregates of A beta deposited on hippocampal neurons in AD could appropriately activate the CaR, stimulating Ca(2+)-permeable channels and causing sustained elevation of Cai with resultant neuronal dysfunction.
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Deng F, Wang G, Du Y, Ye C, Kong Y, Li X. 1H MAS and 1H[23Na] double resonance NMR studies on the modification of surface hydroxyl groups of gamma-alumina by sodium. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1997; 7:281-290. [PMID: 9176933 DOI: 10.1016/s0926-2040(96)01281-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The modification of surface hydroxyl groups with sodium in a series of Na2CO3-gamma-Al2O3 catalysts was investigated as a function of both the Na2CO3 loading and the calcination temperature by means of 1H magic angle spinning (MAS) and 1H(23Na) spin-echo double resonance NMR techniques. The 1H NMR experiments revealed that sodium ions are homogeneously distributed over the alumina surface and closely coordinated with the surface hydroxyl groups. In the catalysts calcined at 250 degrees C, the acidic hydroxyl groups (with a chemical shift of 2.0 ppm) are preferentially associated with sodium ions at low Na2CO3 coverages (5 and 10%), while both the acidic and the basic (0 ppm) hydroxyl groups are accessible for sodium ions at high coverages (15 and 20%). The coordination causes a low-field shift of about 2 ppm in the 1H MAS spectra, and a broad signal at 4.5 ppm appears. It is interesting that the 4.5 ppm signal is completely suppressed in the 1H(23Na) MAS experiments, providing direct evidence that a strong interaction exists between adsorbed sodium ions and the surface hydroxyl groups. Increasing the calcination temperature to 450 degrees C results in preferential removal of the acidic hydroxyl groups, and only the most basic hydroxyl groups remain when the calcination temperature is raised to 600 degrees C. This is attributed to the formation of the coordinated species. [formula: see text] which enhances the acidity of the surface hydroxyl groups and prompts their dehydroxylation, especially at high calcination temperature. Correlation of the 1H MAS NMR results and catalytic activity measurements indicates that the basic hydroxyl groups are essential for the carbonyl sulfide hydrolysis reaction.
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Chen K, Zhang J, Ye C. [Metallothionein involvement in the delayed protection after ischemic or anoxic preconditioning in myocardium or cultured cardiomyocytes]. ZHONGHUA YI XUE ZA ZHI 1997; 77:106-10. [PMID: 9596940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To study whether metallothionein (MT) is an OH scavenger and plays a protective role in cardiac ischemic/reperfusion injury. MT involves in the delayed protection 24 hr after preconditioning (PC). METHODS MT contents in myocardium or cultured cardiomyocytes are assayed at the 0 hr, 12 hr, and 24 hr after PC on the model of rabbit heart in situ or that of the cultured cardiomyocytes. The myocardial infarct size, LDH release, cell viability, and the content of cellular MDA were measured with or without the intervention of PD098059, the inhibitor of mitogen-activated protein kinase in the models before PC and different time intervals after PC. RESULTS The MT contents were increased significantly at 2 hr (1406.2 +/- 112.2 vs 129.9 +/- 10.4 pmol/mg Pr., P < 0.01, in cardiomyocytes) and 24 hr (1032.7 +/- 199.1 vs 129.9 +/- 10.4 pmol/mg Pr., P < 0.01, in cardiomyocytes; 62.1 +/- 12.6 vs 27.2 +/- 3.7 pmol/mg Pr., P < 0.01, in myocardium) after PC compared with those in normal group. The infarct sizes (13.2 +/- 3.6% vs 32.3 +/- 5.7%, P < 0.05) and the rise of LDH release in plasma (1944 +/- 256 vs 2826 +/- 239 IU/L, P < 0.05) were greatly decreased in preconditioned myocardium after a long time ischemia-reperfusion than those in the unpreconditioned. Compared with the cardiomyocytes unconditioned, the number of viable cell (71.0 +/- 1.6 vs 48.2 +/- 2.2%, P < 0.01) was greatly increased, the cellular MDA contents (33.5 +/- 12.8 vs 103.5 +/- 15.0 nmol/mg Pr., P < 0.01) and the LDH release (850.0 +/- 139.1 vs 1552.0 +/- 102.6 IU/L, P < 0.01) were dramatically decreased in preconditioned ones. All the delayed protection at 24 hr after PC were completely disappeared with the inhibition of MT's production with PD098059 (P > 0.05). CONCLUSION The myocardium or cardiomyocytes at 24 hr after PC are offered more capacity to tolerate the I/R damage, and MT involves in the delayed protection.
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Zhou J, Fu R, Hu JZ, Li L, Ye C. Measurement of spin-lattice relaxation times of 13C in organic solids. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1997; 7:291-299. [PMID: 9176934 DOI: 10.1016/s0926-2040(96)01283-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A transient nuclear Overhauser effect (NOE) makes measurements of the 13C spin-lattice relaxation times in organic solids complicated. Extended Solomon equations are applied in order to describe 13C spin-lattice relaxation with 1H r.f. field irradiation. Spin-lattice relaxation under r.f. irradiation is shown to be generally a triple-exponential process, but it can be reduced to be single-exponential under stronger r.f. field irradiation as well as in the absence of 1H initial magnetizations. Based on numerical calculations, the difference between spin-lattice relaxation curves obeying T1C < T1H and those obeying T1C > T1H is clearly indicated. The methyl group resonances in solid-state L-valine are examined, and the experimental results agree well with the theoretical results.
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Vassilev PM, Kanazirska MP, Ye C, Francis J, Hong K, Brown EM. A flickery block of a K+ channel mediated by extracellular Ca2+ and other agonists of the Ca2+-sensing receptors in dispersed bovine parathyroid cells. Biochem Biophys Res Commun 1997; 230:616-23. [PMID: 9015373 DOI: 10.1006/bbrc.1996.6017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Single K+ channel activities in parathyroid cells were studied using the patch-clamp technique. A K+ channel modulated by external Ca2+ (Ca2+o) was identified. This channel had a unitary conductance of 109pS at 150 mM K+o in the pipette solution. An increase in Ca2+o from 0.5-0.75 to 2-3 mM induced a flickery partial block of the channel over a wide voltage range. The mechanism of channel blockade included a significant increase in the number of closings per burst and a reduction of the mean open times. Addition of other divalent and polyvalent agonists of the Ca2+-sensing receptor (CaR) induced a similar channel blockade. With its typical characteristics and flickery block by CaR agonists, this channel differs from previously described types of K+ channels. It is probably strongly coupled to the CaR and may contribute to the depolarization of parathyroid cells which is known to occur at elevated levels of Ca2+o.
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Xie X, Ye C. [Clinical analysis of 120 patients with fibromyalgia]. HUNAN YI KE DA XUE XUE BAO = HUNAN YIKE DAXUE XUEBAO = BULLETIN OF HUNAN MEDICAL UNIVERSITY 1997; 22:167-70. [PMID: 9868064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
The clinical characteristics of 120 patients with fibromyalgia is reported. Most of the patients were 21-50 years old. More than 56% patients had three chief symptoms: generalized myalgia, abnormal sensations and easily fatigue. 49.2% of the patients complained multiple arthralgia; 29% with sleep disorder and 23% with local myospasm of lower limbs. The trigger point was regarded as an important physical sign. The etiology and differential diagnosis for fibromyalgia were discussed.
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Ye C, Ho-Pao CL, Kanazirska M, Quinn S, Seidman CE, Seidman JG, Brown EM, Vassilev PM. Deficient cation channel regulation in neurons from mice with targeted disruption of the extracellular Ca2+-sensing receptor gene. Brain Res Bull 1997; 44:75-84. [PMID: 9288833 DOI: 10.1016/s0361-9230(97)00088-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study presents evidence that a receptor sensitive to the concentration of extracellular Ca2+ (Ca[2+]o) (CaR) is functionally coupled to ion channels involved in modulation of neuronal excitability. This receptor is expressed in hippocampus and other brain regions, suggesting that it could mediate some of the well-recognized but poorly understood direct actions of extracellular Ca2+ (Ca[2+]o) on neuronal function. The effects of polycationic CaR agonists on the activity of a nonselective cation channel (NCC) in cultured hippocampal neurons from wild-type mice and from mice homozygous for targeted disruption of the CaR gene (CaR -/-) were compared in this study. The CaR agonists, neomycin (100 microM), spermine (300 microM), and elevation of Ca(2+)o from 0.75 to 3 mM, significantly increased the probability of channel opening (Po) in wild-type neurons. None of these agents, however, produced any effect on Po in neurons from mice lacking the CaR. The same NCC, however, could be activated by thapsigargin in neurons from both wild-type mice and CaR-deficient mice, most likely through an associated increase in the cytosolic free calcium concentration (Ca[i]). Thus the CaR regulates the activity of Ca2+-permeable NCC in hippocampal neurons and could potentially modulate key neuronal functions, including neurotransmission and neuronal excitability, via membrane depolarization.
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Otto IC, Ito K, Ye C, Hibi K, Kasai Y, Akiyama S, Takagi H. Causes of rectal incontinence after sphincter-preserving operations for rectal cancer. Dis Colon Rectum 1996; 39:1423-7. [PMID: 8969670 DOI: 10.1007/bf02054533] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Low anterior resection (LAR) is the treatment of choice for middle and high rectal tumors. Even though the rectal sphincter is preserved, some patients show a postoperative loss of rectal continence that may be recovered during follow-up. The purpose of this study was to collect clinical and manometric data before and after LAR to find possible explanations for incontinence. METHODS Seventeen continent patients with rectal tumors located 10 cm above the anal verge were selected. Manometry was performed before and three months after surgery and when stable frequency of bowel movement was achieved (mean, 7 months). RESULTS Immediately after the operations, 14 of 17 patients showed a certain degree of incontinence but recovered during follow-up; at the end of the study, only two patients reported minor soiling. Resting and squeeze pressures were moderately reduced after surgery and increased during the following six months without regaining preoperative levels. Rectoanal inhibitory reflex was present in 94.4 percent of patients before the operations and in 25 percent of them after surgery, but it was not associated with incontinence. Rectal sensation was significantly reduced, and its recovery was well correlated with decrease in the frequency of bowel movements. CONCLUSIONS After LAR, there is a reduction in rectal pressures, suggesting damage to sphincter muscle fibers or innervation. There is also a reduction in rectal sensation related to loss in reservoir capacity, all of which may contribute to incontinence.
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Chen S, Lin Z, Ye C, Xu E. Long-term results of intravesical N-CWS therapy for preventing bladder cancer recurrence after operation. Chin Med J (Engl) 1996; 109:890-1. [PMID: 9275378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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189
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Ye C, Rogers K, Bai M, Quinn SJ, Brown EM, Vassilev PM. Agonists of the Ca(2+)-sensing receptor (CaR) activate nonselective cation channels in HEK293 cells stably transfected with the human CaR. Biochem Biophys Res Commun 1996; 226:572-9. [PMID: 8806675 DOI: 10.1006/bbrc.1996.1396] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Calcium (Ca2+) ions serve multiple roles both intra- and extracellularly. We recently cloned a cell surface, Cao(2+)-sensing receptor (CaR) that plays a central role in Cao2+ homeostasis by enabling direct regulation by Cao2+ of parathyroid hormone (PTH) secretion and the function of other tissues involved in mineral ion homeostasis. In parathyroid cells, the CaR activates phospholipase C, thereby raising the levels of inositol trisphosphate (IP3) and releasing Ca2+ from intracellular stores. High Cao2+ also activates Ca2+ influx into parathyroid cells through poorly defined mechanisms that may involve Ca(2+)-permeable, nonselective cation channels (NCC). We now show that human embryonic kidney (HEK293) cells also have NCC and, furthermore, that these channels are regulated by the CaR. We have utilized the cell-attached configuration of the patch clamp technique to characterize the properties of these channels as well as their regulation by various CaR agonists added to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Cao2+ (3 mM), both of which activate the cloned CaR, significantly increased the probability of channel opening (Po) in HEK cells stably transfected with the CaR but not in nontransfected HEK cells which do not contain the receptor. Thus, the activation of the CaR enhances the activity of Ca(2+)-permeable NCC in these cells, which could contribute to the sustained increase in Cai2+ in parathyroid cells which is observed in response to elevated Cao2+. The CaR may also regulate the membrane functions of other CaR-expressing cells (e.g., those in the brain), at least in part, by modulating similar channels.
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Ye C, Kanazirska M, Quinn S, Brown EM, Vassilev PM. Modulation by polycationic Ca(2+)-sensing receptor agonists of nonselective cation channels in rat hippocampal neurons. Biochem Biophys Res Commun 1996; 224:271-80. [PMID: 8694826 DOI: 10.1006/bbrc.1996.1019] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We recently cloned an extracellular calcium (Ca2+0)-sensing receptor (CaR) from bovine parathyroid. The CaR is also expressed in various regions of brain, suggesting that it could potentially mediate some of the well-known but poorly understood effects of Ca2+0 on neuronal function. We have now examined the effects of polycationic CaR agonists on the activity of nonselective cation channels (NCC) in cultured rat hippocampal neurons, using the cell-attached configuration of the patch clamp technique and applying CaR active agents to the external bath solution. The polycationic CaR agonist, neomycin (100 microM), as well as an elevated concentration of Ca2+0 (3 mM), which is known to activate the cloned CaR, significantly increased the probability of channel opening (Po). The polyamine, spermine (300 microM), which also mimics the actions of Ca2+0 on the cloned CaR, produced similar changes in Po in rat hippocampal neurons. Elevation of Ca2+0 also increased Po for a similar NCC in HEK293 cells transfected with the cloned human CaR but not in nontransfected HEK cells. Thus the CaR can regulate the activity of Ca(2+)-permeable NCC in hippocampal neurons and could potentially modulate key functions of these cells, including neurotransmission and neuronal excitability.
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191
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Zhou J, Yang B, Hu J, Hu H, Li L, Qiu J, Zeng F, Ye C. Investigation of a naphthalene pitch by high-resolution solid-state dynamic nuclear polarization. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1996; 6:127-133. [PMID: 8784951 DOI: 10.1016/0926-2040(95)01218-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The possibility of applying the dynamic nuclear polarization (DNP) technique to a study of char is explored with a naphthalene-derived pitch. It is shown that a 13C DNP enhancement factor of about 10(2) is obtained when the polarization is directly transferred from the unpaired electrons to the 13C nuclei. An undistorted spectrum with an enhancement factor of 8 is obtained by the DNP cross-polarization magic-angle spinning nuclear magnetic resonance (DNP-CP-MAS NMR) method. With such a high increase in S/N, it is possible to measure the 13C polarization time (Tp) and the spin-lattice relaxation time (T1) of the system in a reasonable experimental time. The resultant values are Tp = 19 s and T1 = 38 s, respectively. Based on the DNP enhancement as a function of the microwave frequency, it is found that the predominant DNP mechanism in the pitch is the solid-state effect.
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Hu JZ, Wu X, Yang N, Li L, Ye C, Qin K. Spectral editing in 13C CP/MAS experiments at high magnetic field. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1996; 6:187-196. [PMID: 8784957 DOI: 10.1016/0926-2040(95)01203-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We show that the spinning side-bands of protonated and non-protonated carbon atoms can be well separated by means of the standard SCP and LCPD experiments at a relatively slow sample spinning rate or at high magnetic field. These experiments offer a promising way of measuring the principal values of chemical shift anisotropies via spinning side-band analysis in a moderately complex system. General spectral editing in 13C cross-polarization magic-angle spinning (CP/MAS) experiments at high field is achieved by incorporating the total side-band suppression (TOSS) pulse sequence into the standard series of spectral editing pulse sequences. It is confirmed that the relative signal intensity for a certain kind of functional group obtained at different polarization, polarization-inversion and depolarization times is about the same as that obtained at low magnetic field, and that the signal intensity distortion introduced by the TOSS sequence for resonances having different chemical shift anisotropies does not interfere with the spectral editing process. However, quantitative results can only be expected in those cases where full restoration of the intensity of the central band can be achieved by the TOSS sequence. This new strategy at high field is demonstrated by using fumaric acid monoethyl ester as a model compound. A typical application to a Chinese resin is presented, where the relative ratio of each functional group in the aliphatic portion to the total number of aliphatic carbon atoms is determined from only three experimental spectra.
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Hu JZ, Zhou J, Deng F, Feng H, Yang N, Li L, Ye C. High resolution 1H spectra of powdered solids observed by Hahn echo pulse sequence with magic-angle spinning. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1996; 6:85-94. [PMID: 8925269 DOI: 10.1016/0926-2040(95)01212-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The 1H magic-angle spinning (MAS) spectrum for a typical powdered solid is composed of a high resolution component and a broadline component. The high resolution component can be well isolated from the broadline component by the Hahn echo sequence with a long echo time. Compared with CRAMPS experiment, which measures the proton system as a whole, the high resolution echo-MAS method measures only a fraction of the solid, which is usually small at room temperature and quite different from the majority of the solid in both molecular motion and chemical environment. It is shown that for a sample of fumaric acid monoethyl ester, the chemical shifts of the high resolution component are apparently distinguishable from the isotropic chemical shifts of the broadline component in the CRAMPS spectrum as the temperature approaches the melting point. In addition, for a sample of malonic acid, the echo-MAS spectrum is sensitive to moisture and temperature, while its corresponding CRAMPS spectrum is not. It is suggested that the molecules which produce the high resolution component are related to the lattice defects in a solid, including the surface disorder of the polycrystallites, while the molecules that generate the broadline component are located on the rigid lattice of the solid.
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Wang Y, Xu G, Ye C, Zhao J, Zhou S, Liu Y. Observation of transparency and population trapping due to atomic coherent effects. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1996; 53:1160-1163. [PMID: 9912995 DOI: 10.1103/physreva.53.1160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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195
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Gerstein BC, Hu JZ, Zhou J, Ye C, Solum M, Pugmire R, Grant DM. The use of differential transverse relaxation to detect mobile species in solids. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1996; 6:63-71. [PMID: 8925267 DOI: 10.1016/0926-2040(95)01211-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Delayed acquisition of the proton NMR in selected organic molecular solids (L-alanine, durene, ethyl fumarate, and p-hydroxybenzoic acid) is shown to allow the observation of mobile species in the presence of relatively rigid bulk molecules. The mobility is found to be thermally activated. The combination of the thermally activated motion and magic-angle spinning leads to a fraction of these species moving nearly isotropically on the time scale of the inverse of the homonuclear dipolar splitting. In the case of ethyl fumarate and alanine, there exist populations with differing values of T1 and T1 row. This indicates the co-existence of relatively rigid and relatively mobile molecules in the same sample. The intensities under delayed acquisition cannot always be trusted to yield quantitative information. Comparison of spectra taken under delayed acquisition and under the CRAMPS (B.C. Gerstein, R.G. Pembleton, R.C. Wilson and L.M. Ryan, J. Chem. Phys., 66 (1977)361) technique is made.
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Yue X, Ye C, Zhao P, Gou D. Long-term survival of heterotopic heart transplants in allogenic rats without using anti-rejection drugs after inducing immune tolerance. Chin Med J (Engl) 1995; 108:887-91. [PMID: 8728937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Graft rejection is a baffling problem in organ transplantation which has so far no successful resolution. Present antirejection therapy is expensive, toxic, susceptible to infection, oncogenesis and atherosclerosis. With the use of 2 extremely histoincompatible strains of rats as model, it was found that when six donor splenocytes preconditioned by an extract from the culture medium of streptomyces caespitosus were injected into the host, after 2 weeks immune tolerance heterotopic transplanted donor hearts could survive normally more than 100 days without using any anti-rejection drug. Their mean survival time was 141.4 +/- 2.56 days, while that in the control group was only 11.7 +/- 3.48 days (P < 0.005). Thus, the present research offers some bright prospects in the area of organ transplantation.
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197
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Zhou J, Ye C. A novel disentangling technique for the propagator describing cross-polarization dynamics. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1995; 5:213-216. [PMID: 9053111 DOI: 10.1016/0926-2040(95)00029-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The heteronuclear cross-polarization dynamics is described by the rotation operator approach proposed recently. The established theory is suitable for an isolated two-spin system. It is shown that the propagator can be disentangled into a cascade of six exponential operators and the polarization transfer concerned can be evaluated by the usual procedure.
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198
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Xia Y, Deng F, Ye C. Off-resonance effects on 2D NMR nutation spectra of I = 3/2 quadrupolar nuclei in static samples. SOLID STATE NUCLEAR MAGNETIC RESONANCE 1995; 5:227-232. [PMID: 9053113 DOI: 10.1016/0926-2040(95)01185-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The off-resonance effects on 2D NMR nutation of I = 3/2 quadrupolar nuclei are demonstrated with perturbation theory and numerical calculation in static samples. The off-resonant (delta omega) rf field (omega 1) enlarges a nutation frequency and consequently increases the measurement range of nuclear quadrupolar interaction parameters. When omega e > omega Qmax, and arctg(omega 1/delta omega) = +/- 54.7 degrees (magic angle), the satellite lines (produced by coherence transfers) in a nutation spectrum are superimposed with the line of central transition, and hence the nutation spectrum is simplified and its sensitivity is enhanced. The nuclear quadrupolar interaction parameters of 23Na nuclei in Na omega molecular sieve are obtained using 2D NMR nutation.
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199
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Kiriyama K, Ye C. [E-selectin expression in serum and tissue correlates with distant metastasis of colorectal cancer]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 1995; 53:1760-4. [PMID: 7543166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
E-selectin is an adhesion molecule of endothelial cells that binds to cancer cells mediated by sialyl Lewis A (sLea) or sialyl Lewis X (sLex). It is suspected to be involved in hematogenous metastasis of tumors. Therefore, it is worth examining E-selectin expression in human colorectal cancer and its hepatic metastasis. In the present study, E-selectin was clearly revealed on the endothelial cells of small vessels adjacent to cancer nests in both primary and metastatic nests in immunohistochemistry. In these tissues, E-selectin was observed on the endothelial cells lining the lumen of small vessels. Its expression adjacent to cancer nests appears to be induced through some stimuli by cancer cells, since its degree of expression is inversely correlated to the distance of the blood vessels from the cancer nests (P < 0.001). Endothelial cells adjacent to the metastatic lesion expressed E-selectin more extensively than those adjacent to the primary foci. This is also in line with the finding on serum E-selectin levels which were significantly elevated in the metastatic group compared to the non-metastatic group. The serum E-selectin level may provide useful information in the diagnosis for hepatic metastasis of colorectal cancer, although the results are still very preliminary.
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200
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Ye C, Kiriyama K, Mistuoka C, Kannagi R, Ito K, Watanabe T, Kondo K, Akiyama S, Takagi H. Expression of E-selectin on endothelial cells of small veins in human colorectal cancer. Int J Cancer 1995; 61:455-60. [PMID: 7538975 DOI: 10.1002/ijc.2910610404] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
E-selectin is an adhesion molecule of endothelial cells that binds to cancer cells mediated by sialyl Lewis A (sLea) or sialyl Lewis X (sLe(x)). It is suspected to be involved in hematogenous metastasis of tumors. Therefore, it is worth examining E-selectin expression in human colorectal cancer and its hepatic metastasis. In the present study, E-selectin was clearly revealed on the endothelial cells of small vessels adjacent to cancer nests both in primary and in metastatic nests in immunohistochemistry. In these tissues, E-selectin was observed on the endothelial cells lining the lumen of small vessels. Its expression adjacent to cancer nests appears to be induced through some stimuli by cancer cells, since its degree of expression is inversely correlated to the distance of the blood vessels from the cancer nests (p < 0.001). Endothelial cells adjacent to the metastatic lesion expressed E-selectin more extensively than those adjacent to the primary foci. This is also in line with the finding on serum E-selectin levels which were significantly elevated in the metastatic group as compared with the non-metastatic group. The serum E-selectin level may provide useful information in the diagnosis for hepatic metastasis of colorectal cancer, although the results are still tentative.
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