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Liu SQ, Fung YC. Changes in the organization of the smooth muscle cells in rat vein grafts. Ann Biomed Eng 1998; 26:86-95. [PMID: 10355553 DOI: 10.1114/1.52] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Mechanical tensile stress in vein grafts increases suddenly under the influence of arterial blood pressure. In this study, we examined the influence of increased tensile stress on the organization of the smooth muscle cells (SMCs) in the neointima and media of the rat vein grafts. An autogenous jugular vein was grafted into the abdominal aorta of the rat, and changes in the organization of the vein graft SMCs were studied by observing the distribution of SMC actin filaments and nuclei at 3 min and 1, 5, 10, and 30 days after surgery. In a normal jugular vein, the average wall circumferential tensile stress was approximately 3 kPa at an internal pressure of 3 mm Hg. The SMCs, that contained long, slender actin filamentous bundles, were oriented mainly in the circumferential direction of the vessel, and constituted a 2- to 3-cell-thick medial layer underneath the endothelium. In a vein graft, the wall circumferential tensile stress suddenly increased by approximately 140 times compared with the control level. In response to this suddenly increased stress, the SMC layer was stretched into a structure with scattered pores and disrupted SMC actin filamentous bundles within 3 min. This initial change was followed by a rapid reduction in the density of the SMC nuclei and actin filaments within 1 day and progressive SMC proliferation, that was associated with medial thickening and a change in the SMC orientation from 5 to 30 days. Further studies showed that a local inflation of normal jugular veins to 120 mm Hg for 3 min induced a similar change as found in the vein grafts, whereas the organization of the SMCs was not significantly changed in vein-vein grafts, that did not experience a change in tensile stress. These results suggested that increased tensile stress contributed to the initial damage of the SMCs and played a role in the regulation of medial SMC remodeling in vein grafts.
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77
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Wu Y, Aghdasi B, Dou SJ, Zhang JZ, Liu SQ, Hamilton SL. Functional interactions between cytoplasmic domains of the skeletal muscle Ca2+ release channel. J Biol Chem 1997; 272:25051-61. [PMID: 9312113 DOI: 10.1074/jbc.272.40.25051] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The skeletal muscle Ca2+ release channel (RYR1), which plays a critical role in excitation-contraction coupling, is a homotetramer with a subunit molecular mass of 565 kDa. Oxidation of the channel increases its activity and produces intersubunit cross-links within the RYR1 tetramer (Aghdasi, B., Zhang, J., Wu, Y., Reid, M. B., and Hamilton, S. L. (1997) J. Biol. Chem. 272, 3739-3748). Alkylation of hyperreactive sulfhydryls on RYR1 with N-ethylmaleimide (NEM) inhibits channel function and blocks the intersubunit cross-linking. We used calpain and tryptic cleavage, two-dimensional SDS-polyacrylamide gel electrophoresis, N-terminal sequencing, sequence-specific antibody Western blotting, and [14C]NEM labeling to identify the domains involved in these effects. Our data are consistent with a model in which 1) diamide, an oxidizing agent, simultaneously produces an intermolecular cross-link between adjacent subunits within the RYR1 tetramer and an intramolecular cross-link within a single subunit; 2) all of the cysteines involved in both cross-links are in either the region between amino acids approximately 2100 and 2843 or the region between amino acids 2844 and 4685; 3) oxidation exposes a new calpain cleavage site in the central domain of the RYR1 (in the region around amino acid 2100); 4) sulfhydryls that react most rapidly with NEM are located in the N-terminal domain (between amino acids 426 and 1396); 5) alkylation of the N-terminal cysteines completely inhibits the formation of both inter- and intrasubunit cross-links. In summary, we present evidence for interactions between the N-terminal region and the putatively cytoplasmic central domains of RYR1 that appear to influence subunit-subunit interactions and channel activity.
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78
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Liu SQ, Chen YS, Wu NJ, Ignatiev A. Realization of a polarizer employing the combined effects of birefringence and diffraction. OPTICS LETTERS 1997; 22:1518-1520. [PMID: 18188287 DOI: 10.1364/ol.22.001518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A polarizer that uses the combined effects of birefringence and diffraction has been realized experimentally. A sheet of calcite was taken as the substrate, and a series of grooves with a sawtooth profile was manufactured on its surface by optical grinding and polishing. The sample polarizer shows good polarizing performance in test. The measured extinction ratio is better than 2 x 10(-4) and can be improved further.
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Xue SP, Zhang SF, Du Q, Sun H, Xin J, Liu SQ, Ma J. The role of cytoskeletal elements in the two-phase denucleation process of mammalian erythroblasts in vitro observed by laser confocal scanning microscope. Cell Mol Biol (Noisy-le-grand) 1997; 43:851-60. [PMID: 9359632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The cytoskeletal elements in the denucleation processes were observed using immunofluorescence and laser confocal scanning microscopy in the Friend virus (FVA) infected splenic erythroblasts of BALB/c mice. When cultured in the presence of erythropoietin (EPO), it was shown that the synchronized erythroid precursor cells proceeded to an autonomous nuclear extrusion when the three types of cytoskeletal elements were observed contributing to different phases of that process. The vimentin intermediate filament (IF) was shown as the nuclear anchorage elements with binding sites anchored from the nuclear lamina to the center as well as to the plasma membrane periphery. A dense perinuclear layer of vimentin fluorescence in erythroblasts was observable during the periods of 12, 24 and 36 hrs. in vitro culture. The amount of vimentin IF per cell was higher than that of tubulin and F-actin at 12-24 hrs. culture, but the vimentin filaments were observed to brake down and decreased steadily when the cells became differentiated into late erythroblasts at 36-48 hrs. Such an attenuation of vimentin filaments may facilitate the eccentric movement of the nucleus which can be regarded as the initial step (phase) of denucleation. The fluorescent intensity of tubulin and actin exhibited a significant rise and aggregated between the extruding nucleus and the incipient reticulocyte prior to and during the processes of denucleation, what indicated that the actin filaments and microtubules may play roles in the second phase of the denucleation process, or final commitment of enucleation. The erythroid differentiation-denucleation factor (EDDF), as an intrinsic factor, involved in the denucleation events, was also discussed.
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80
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Pei XJ, Liu SQ, Zhang XY. [Improving nursing administration to increase level of clinical nursing research]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1997; 32:272-3. [PMID: 9304990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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81
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Liu SQ. Regression of hypoxic hypertension-induced changes in the elastic laminae of rat pulmonary arteries. J Appl Physiol (1985) 1997; 82:1677-84. [PMID: 9134919 DOI: 10.1152/jappl.1997.82.5.1677] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The elastic laminae of the pulmonary arteries (PAs) undergo a progressive structural change in hypoxic hypertension. This study focused on the reversibility of altered PA elastic laminae of the rat due to hypoxic hypertension. The structure and cross-sectional area of the PA medial elastic laminae were examined by using electron-microscopic and image-analytic approaches during recovery from 12 h and 10 days of hypoxic hypertension. At 12 h of hypoxic hypertension, the elastic laminae, which appeared homogeneous in normal control animals, were reorganized into structures composed of randomly oriented filaments, with an increase in the cross-sectional area of 70%. At 10 days of hypoxic hypertension, the elastic laminae appeared homogeneous in structure and normal in cross-sectional area despite continuous exposure to hypoxia. During recovery from 12 h of hypoxic hypertension, the medial elastic laminae regained their homogeneous structure and normal cross-sectional area after day 2. During recovery from 10 days of hypoxic hypertension, the medial elastic laminae changed from homogeneous to filamentous structures, with a progressively altered cross-sectional area that increased by 89% from recovery day 0 to day 10 and returned to the normal level on day 30. These changes were associated with alterations in the PA wall tensile stress. These results indicated that structural changes in the PA elastic laminae were reversible and that the regression process depended on the duration of exposure to hypoxia, the state of the elastic laminae, and possibly the tensile stress level in the PA wall.
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82
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Liu SQ, Shiraiwa H, Kawai K, Hayashi H, Akaza H, Kim BS, Oki A, Nishida M, Kubo T, Hashizaki K, Saijo K, Ohno T. Tumor-specific autologous cytotoxic T lymphocytes from tissue sections. Nat Med 1996; 2:1283. [PMID: 8946818 DOI: 10.1038/nm1296-1283] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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83
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Dou LR, Huang YJ, Liu SQ. [Postoperative care following rotatory plasty in children with malignant tumor of the distal end of the femur]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1996; 31:650-651. [PMID: 9304926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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84
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Liu SQ. Alterations in structure of elastic laminae of rat pulmonary arteries in hypoxic hypertension. J Appl Physiol (1985) 1996; 81:2147-55. [PMID: 8941540 DOI: 10.1152/jappl.1996.81.5.2147] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The effect of hypoxic hypertension on the remodeling process of the elastic laminae of the rat hilar pulmonary arteries (PAs) was studied by electron microscopy. Rats were exposed to hypoxia (10% O2) for periods of 0.5, 2,6,12,48,96,144, and 240 h. Changes in the structure of the PA elastic laminae were examined and analyzed with respect to changes in the PA wall tensile stress. The PA blood pressure increased rapidly within the first several hours of hypoxia and reached a stable level within 2 days, whereas the PA wall tensile stress increased initially due to elevated blood pressure and then decreased after 48 h due to vessel wall thickening and returned to the control level after 4 days. In association with these changes, the elastic laminae, which appeared homogeneous in normal control rats, changed into structures composed of randomly oriented filaments and edematous contents with an increase in the volume during the early period of hypoxia and regained their homogeneous appearance and normal volume after 4 days. The changes in the elastic laminae were correlated with changes in the tensile stress. These changes were associated with a transient decrease in the stiffness of the PAs. In hypoxic rats given nifedipine, no change was found in the blood pressure, the tensile stress, or the structure of the elastic laminae of the PAs despite continuous exposure to hypoxia. These results suggested that altered tensile stress in the PA wall played a critical role in the initiation and regulation of structural changes in the elastic laminae and that these changes might contribute to alterations in the mechanical properties of the PA in hypoxic hypertension.
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85
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Wang JP, Needleman DH, Seryshev AB, Aghdasi B, Slavik KJ, Liu SQ, Pedersen SE, Hamilton SL. Interaction between ryanodine and neomycin binding sites on Ca2+ release channel from skeletal muscle sarcoplasmic reticulum. J Biol Chem 1996; 271:8387-93. [PMID: 8626537 DOI: 10.1074/jbc.271.14.8387] [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: 01/31/2023] Open
Abstract
Neomycin is a potent inhibitor of skeletal muscle sarcoplasmic reticulum (SR) calcium release. To elucidate the mechanism of inhibition, the effects of neomycin on the binding of [3H]ryanodine to the Ca2+ release channel and on its channel activity when reconstituted into planar lipid bilayer were examined. Equilibrium binding of [3H]ryanodine was partially inhibited by neomycin. Inhibition was incomplete at high neomycin concentrations, indicating noncompetitive inhibition rather than direct competitive inhibition. Neomycin and [3H]ryanodine can bind to the channel simultaneously and, if [3H]ryanodine is bound first, the addition of neomycin will slow the dissociation of [3H]ryanodine from the high affinity site. Neomycin also slows the association of [3H]ryanodine with the high affinity binding site. The neomycin binding site, therefore, appears to be distinct from the ryanodine binding site. Dissociation of [3H]ryanodine from trypsin-treated membranes or from a solubilized 14 S complex is also slowed by neomycin. This complex is composed of polypeptides derived from the carboxyl terminus of the Ca2+ release channel after Arg-4475 (Callaway, C., Seryshev, A., Wang, J. P., Slavik, K., Needleman, D. H., Cantu, C., Wu, Y., Jayaraman, T., Marks, A. R., and Hamilton, S. L. (1994) J. Biol. Chem. 269, 15876-15884). The proteolytic 14 S complex isolated with ryanodine bound produces a channel upon reconstitution into planar lipid bilayers, and its activity is inhibited by neomycin. Our data are consistent with a model in which the ryanodine binding sites, the neomycin binding sites, and the channel-forming portion of the Ca2+ release channel are located between Arg-4475 and the carboxyl terminus.
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86
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Liu SQ, Fung YC. Indicial functions of arterial remodeling in response to locally altered blood pressure. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 270:H1323-33. [PMID: 8967372 DOI: 10.1152/ajpheart.1996.270.4.h1323] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We investigated the effect of locally altered blood pressure on the remodeling processes of the cells and extracellular matrices of the splenic and ileal arteries and used an indicial function approach to quantitatively analyze the relationship between the altered blood pressure and the remodeling processes. Blood pressure in these arteries was locally modulated by constricting the aorta at a location between the celiac and mesenteric bifurcations, resulting in a higher blood pressure at the splenic arteries then at the ileal arteries, After the pressure changes, the cross-sectional areas and the fractions of the cells and extracellular matrices of the splenic and ileal arteries were examined by electron microscopy at 2, 6, 10, 20, and 30 days. We found that both arteries remodeled, but the splenic arteries (higher blood pressure) remodeled more rapidly and to a larger degree than the ileal arteries (lower pressure compared with the splenic arteries) of the same animal. To verify whether an identical change in the blood pressure at the splenic and ileal arteries leads to the same remodeling process in these arteries, we created another model by constricting the aorta at a location between the mesenteric and renal bifurcations, resulting in hypertension of the same level at both splenic and ileal arteries. We found that the remodeling processes of the cells and matrices were almost identical in the arteries with similar changes in blood pressure. Thus we conclude that the remodeling processes of cells and matrices of the splenic and ileal arteries are dependent on the local blood pressure in aorta constriction-induced hypertension, and the indicial analysis is a useful approach in the description of the relationship between the blood pressure and the arterial remodeling processes.
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87
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Liu SQ, Ries E, Knauf PA. Effects of external pH on binding of external sulfate, 4.4-dinitro-stilbene-2,2'-disulfonate (DNDS), and chloride to the band 3 anion exchange protein. J Gen Physiol 1996; 107:293-306. [PMID: 8833347 PMCID: PMC2219265 DOI: 10.1085/jgp.107.2.293] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A model in which two positively-charged titratable sites enhance the affinity for anionic substrates can explain the increase in external iodide dissociation constant (K(O)(I)) with increasing pH(O) (Liu, S. J., F.-Y. Law, and P.A. Knauf. 1996.f Gen.Physiol. 107:271-291). If sulfate binds to the same external site as I-, this model predicts that the SO(4)= dissociation constant (K(O)(S)) should also increase. The data at pH 0 8.5 to 10 fit this prediction, and the pK for the titration is not significantly different from that (pKc) for the low-pK group that affects K(O)(1). The dissociation constant for the apparently competitive inhibitor, DNDS (4,4-dinitrostilbene-2,2'-disulfonate), also increases greatly as pH(O) increases. Particularly at high pH(O), a noncompetitive inhibition by DNDS is also evident. Increasing pH(O) from 7.2 to 11.2 increases the competitive dissociation constant by 700-fold, but the noncompetitive is only increased 20-fold. The pK values for these effects are similar to pKc for K(O)(1), as expected if DNDS binds near the external transport site, but it seems likely that additional titratable groups also affect DNDS binding. The apparent affinity for external Cl- is also affected by pH(O), in a manner similar to that observed for I-. Pretreatment with the amino-selective reagent, bis-sulfosuccinimidyl suberate (BSSS), decreases the apparent Cl- affinity at pH 8.5, but two titrations are still evident, the first (lower) of which decreases the apparent C- affinity, and the second of which surprisingly increases it. Thus, the BSSS-reactive amino groups (probably Lys-539 and Lys-851) do not seem to be involved in the titrations that affect Cl- affinity. In general, the data support the concept that a positively charged amino group (or groups), together with a guanidino group, plays an important role in the binding of substrates and inhibitors at or near the external transport site.
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88
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Liu SQ, Law FY, Knauf PA. Effects of external pH on substrate binding and on the inward chloride translocation rate constant of band 3. J Gen Physiol 1996; 107:271-91. [PMID: 8833346 PMCID: PMC2219267 DOI: 10.1085/jgp.107.2.271] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
To test the hypothesis that amino acid residues in band 3 with titratable positive charges play a role in the binding of anions to the outside-facing transport site, we measured the effects of changing external pH (pH(O)) on the dissociation constant for binding of external iodide to the transport site, K(O)(I). K(O)(I) increased with increasing pH(O), and a significant increase was seen even at pH(O) values as low as 9.9. The dependence of K(O)(I) on pH(O) can be explained by a model with one titratable site with pK 9.5 +/- 0.2 (probably lysine), which increases anion affinity for the external transport site when it is in the positively charged form. A more complex model, analogous to one recently proposed by Bjerrum (1992), with two titratable sites, one with pK 9.3 +/- 0.3 (probably lysine) and another with pK > 11 (probably arginine), gives a slightly better fit to the data. Thus, titratable positively charged residues seem to be functionally important for the binding of substrate anions to the outward-facing anion transport site. In addition, analysis of Dixon plot slopes for L inhibition of Cl- exchange at different pH 0 values, coupled with the assumption that pH(O) has parallel effects on external I- and Cl- binding, indicates that k', the rate-constant for inward translocation of the complex of Cl- with the extracellular transport site, decreases with increasing pH(O). The data are compatible with a model in which titration of the pK 9.3 residue decreases k to 14 +/- 10% of its value at neutral pH(O). This result, however, together with Bjerrum's (1992) observation that the maximum flux J(M)) increases 1.6-fold when this residue is deprotonated, makes quantitative predictions that raise significant questions about the adequacy of the two titratable site ping-pong model or the assumptions used in analyzing the data.
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Tsurushima H, Liu SQ, Tsuboi K, Yoshii Y, Nose T, Ohno T. Induction of human autologous cytotoxic T lymphocytes against minced tissues of glioblastoma multiforme. J Neurosurg 1996; 84:258-63. [PMID: 8592229 DOI: 10.3171/jns.1996.84.2.0258] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The authors induced autologous cytotoxic T lymphocytes (CTLs) directly from peripheral blood lymphocytes by preparing a coculture of minced tissue fragments of glioblastoma multiforme (GBM) with interleukins-1, -2, -4, and -6 and interferon-gamma in RHAM alpha medium containing 5% autologous plasma for 2 weeks. At the end of this period, the frequencies of CD3+, CD4+, CD8+, and CD16+ lymphocytes were 95% to 99%, 40% to 62%, 37% to 38%, and 0.2%, respectively. The lymphocytes killed 82% to 100% of the GBM cells within 48 hours at an effector-to-target cell ratio of 1.67, whereas in a separate coculture, autologous lymphokine-activated killer (LAK) cells killed only 33% of GBM cells under the same conditions. The lymphocytes showed no cytotoxicity against LAK-sensitive Daudi cells, natural killer-sensitive K562 cells or autologous fibroblasts grown from the brain tumor, although they did show slight cytotoxicities against allogeneic GBM cell lines. These results lead the authors to suggest that the lymphocyte population contains specific CTLs for autologous brain tumor cells and that these CTLs could be effective in adoptive immunotherapy to combat brain tumor.
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Fung YC, Liu SQ. Determination of the mechanical properties of the different layers of blood vessels in vivo. Proc Natl Acad Sci U S A 1995; 92:2169-73. [PMID: 7892241 PMCID: PMC42445 DOI: 10.1073/pnas.92.6.2169] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The structure and materials of the blood vessel wall are layered. This article presents the principle of a method to determine the mechanical properties of the different layers in vivo. In vivo measurement begets in vivo data and avoids pitfalls of in vitro tests of dissected specimens. With the proposed method, we can measure vessels of diameters 100 microns and up and obtain data on vascular smooth muscles and adventitia. To derive the full constitutive equations, one must first determine the zero-stress state, obtain the morphometric data on the thicknesses of the layers, and make mechanical measurements in the neighborhood of the zero-stress state. Then eight small perturbation experiments are done on earth blood vessel in vivo to determine eight incremental elastic moduli of the two layers of the blood vessel wall. The calculation requires the morphometric data and the location of the neutral axis. The experiments are simple, the interpretation is definitive, but the analysis is somewhat sophisticated. The method will yield results that are needed to assess the stress and strain in the tissues of the blood vessel. The subject is important because blood vessels remodel themselves significantly and rapidly when their stress and strain deviate from their homeostatic values, and because cell proliferation, differentiation, adhesion, contraction, and locomotion depend on stress and strain in the tissue.
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91
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Liu SQ, Saijo K, Todoroki T, Ohno T. Induction of human autologous cytotoxic T lymphocytes on formalin-fixed and paraffin-embedded tumour sections. Nat Med 1995; 1:267-71. [PMID: 7585045 DOI: 10.1038/nm0395-267] [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: 01/26/2023]
Abstract
Human autologous tumour-specific cytotoxic T lymphocytes (CTL) were generated from peripheral blood on small formalin-fixed paraffin-embedded sections of a gastric cancer. The CTL killed live target cells at an effector/target ratio of 1 within 24 hours and showed the same target specificity as those induced on live cancer cells. The killing activity of the CTL lasted for more than four months in culture and was inhibited by antibodies against CD8 and MHC-class I. These results suggest that adoptive immunotherapy of tumours will be possible with CTL induced on a stable source of tumour antigen.
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92
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Li GD, Liu SQ, Ye XY, Qu FY. Detection of 54-kDa protein overexpressed by chloroquine-resistant Plasmodium berghei ANKA strain in pyronaridine-resistant P berghei ANKA strain. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1995; 16:17-20. [PMID: 7771189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
AIM A 54-kDa protein overexpressed by chloroquine-resistant (CR) Plasmodium berghei ANKA strain was first reported by us. This study is conducted to detect the protein in pyronaridine-resistant (PR) P berghei ANKA strain. METHODS Immunoblotting analysis and immunoelectron microscopy were used. RESULTS PR parasites, like CR parasites, mainly overexpressed 2 major bands of 37 (36-38) kDa and 16 (15-17) kDa which were considered to be 2 subunits of 54 (52-62) kDa protein. Three of 7 times of experiments showed a 54-kDa and a 96 (95-100) kDa bands. The proteins were localized to be mainly scattered in cytoplasm of trophozoites, schizonts, and merozoites of erythrocytic stage of P berghei. Some of them were distributed in cytoplasm of erythrocytes infected with parasites. CONCLUSION Both PR and CR parasites overexpressed the same proteins.
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Liu SQ, Shiba R, Kim BS, Saijo K, Ohno T. Long-term serum/plasma-free culture of human cytotoxic T lymphocytes induced from peripheral blood mononuclear cells. Cancer Immunol Immunother 1994; 39:279-85. [PMID: 7987858 PMCID: PMC11038377 DOI: 10.1007/bf01519979] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/1994] [Accepted: 07/08/1994] [Indexed: 01/28/2023]
Abstract
Tumor-specific human cytotoxic T lymphocytes (CTL) were induced by co-culturing peripheral blood mononuclear cells with X-ray-irradiated human lung squamous carcinoma cells, SQ-5, in the medium supplemented with interleukin(IL)-1, IL-2, IL-4 and IL-6, and 5% autologous plasma for 3 or 5 days. The CTL grew in serum/plasma-free medium containing these four interleukins and 0.5% bovine serum albumin for over a month and maintained killing activity of target cells within 48 h at an effector/target ratio of 1.25. Their growth was essentially dependent on the target SQ-5 cells, which were renewed every 5 days. Under these conditions, IL-4 and IL-6 could be omitted. When anti-CD3 monoclonal antibody was added to the serum/plasma-free medium supplemented with IL-1 and IL-2, the target tumor cells were not required to maintain the specific killing activity of the CTL. A large number of CTL (10(11)) were obtained in 35 days.
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Liu SQ, Liu XF, Song SJ. [An immunohistochemical study on megakaryocytes in patients with myelodysplastic syndromes]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 1994; 23:288-90. [PMID: 7874762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
An immunohistochemical study was performed on trephine biopsy specimens of bone marrow in 10 patients with myelodysplastic syndromes (MDS). Monoclonal antibodies HIP7 and CDW41 were used against platelet glycoprotein IIb/IIIa (CD41) to determine dysmegakaryopoiesis including its size, proportion of micromegakaryocytes, location and staining characteristics. The results show that the dysmegakaryopoiesis of MDS includes the increased number and high proportion of micromegakaryocytes, the altered architectural distribution and the considerable variation in staining. These may be helpful in the diagnosis and differential diagnosis of MDS.
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95
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Liu SQ, Yen M, Fung YC. On measuring the third dimension of cultured endothelial cells in shear flow. Proc Natl Acad Sci U S A 1994; 91:8782-6. [PMID: 8090723 PMCID: PMC44690 DOI: 10.1073/pnas.91.19.8782] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The stress in the endothelial cells induced by blood flow depends on the waviness of the blood-endothelium interface and the slopes at the junctions of neighboring cells in the direction of flow. The height and slope in the third dimension of the living endothelial cells cannot be measured by ordinary optical and electron microscopy. Here we show that interference microscopy meets the challenge. We measured the geometry of cultured confluent human vascular endothelial cells in a flow, and we found that in a normal section parallel to the flow, the absolute values of the surface slopes at the cell junctions were 0.70 +/- 0.02 (SE) and 0.80 +/- 0.02 (SE) at the leading and trailing edges of the cells, respectively, in a culture medium of osmolarity 310 mosM with a shear stress of approximately 1 N/m2. A reversal of the flow direction led to a reversal of the slope pattern. An increase in medium osmolarity above 310 mosM induced an initial decrease in the slopes followed by a return to normal, whereas a decrease in the osmolarity had a reversed effect. These results, in light of our previous theoretical analyses, show that tensile stress exists in the endothelial cell membrane, and that the mechanism of tension accumulation is a reality. The accumulation is not 100% because the membranes are not smooth at the cell junctions.
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Bhatnagar A, Liu SQ, Ueno N, Chakrabarti B, Srivastava SK. Human placental aldose reductase: role of Cys-298 in substrate and inhibitor binding. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1205:207-14. [PMID: 8155699 DOI: 10.1016/0167-4838(94)90235-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Steady-state kinetic and inhibition properties of human placental aldose reductase carboxymethylated at Cys-298 were investigated. A comparison of the primary deuterium kinetic isotope effect on the reduced and the carboxymethylated enzymes suggests that carboxymethylation did not affect the reaction sequence of substrate binding and release. Values of DV/KD-glyceraldehyde greater than DV suggest that steps in the reaction scheme subsequent to hydride transfer, particularly the release of NADP may be rate limiting. Carboxymethylation of Cys-298 was also found to affect NADPH and aldehyde binding to the enzyme. Carboxymethylation had little effect on the secondary structure of the enzyme, but a comparison of the circular dichroic spectra of the reduced and carboxymethylated enzyme, suggests a weakened interaction between the nicotinamide and 2'-monophosphoadenosine 5'-diphosphoribose of NADPH, and the carboxymethylated enzyme. Interaction between Cys-298 and NADPH appears to determine the rate of isomerization of the E:NADP binary complex and carboxymethylation-induced decrease in kcat may be due to slower isomerization of the E:NADP binary complex. The carboxymethylated enzyme was less sensitive than the reduced enzyme to most aldose reductase inhibitors including sorbinil (d-6-fluoro-spiro[chroman-4,4'-imidazolidine]-2',5'-dione), except tolrestat (N-methyl-N-[(5-trifluromethyl-6-methoxy-1-naphthalenyl)- thiomethyl]glycine) and quercetin. On the basis of these observations it is suggested that Cys-298 may form a part of the 'S'-inhibitor binding site of the enzyme and may be responsible for tight binding of NADPH.
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97
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Liu SQ, Bhatnagar A, Srivastava SK. Bovine lens aldose reductase. pH-dependence of steady-state kinetic parameters and nucleotide binding. J Biol Chem 1993; 268:25494-9. [PMID: 8244985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The pH-dependence of nucleotide binding and steady-state kinetic parameters of aldehyde reduction and alcohol oxidation catalyzed by bovine lens aldose reductase were studied. The maximal velocity of aldehyde reduction with NADPH and p-chlorobenzaldehyde was pH independent at low pH but decreased at high pH with a pK of 7.6. The V/K of NADPH displayed a bell-shaped dependence on pH and decreased with a pKa of 5.3 and a pKb of 7.5. The dissociation constant of NADPH and 3-acetylpyridine adenine dinucleotide phosphate (3-APADP) increased at low pH with a pK of 5.6-5.8 and at high pH with a pK of 9.4-9.7. The pKi of NADP and NADPH decreased below a pH of 5 and 6.7 and above a pH of 8.5 and 9.7, respectively. The pK of 8.5-9.7 appears to be due to the interaction of the 2'-phosphate of the nucleotide with a protonated base, possibly a lysine residue. The maximal velocity of alcohol oxidation was pH independent at high pH but decreased at low pH with a pK of 6.5-7.0, when p-chlorobenzyl alcohol or benzyl alcohol and 3-APADP were used. The amino acid residue for alcohol binding has a pK of 7.5-8.2 and also appears in pKi profiles of sorbinil, a competitive inhibitor versus the alcohol. Large (3-3.5) isotope effects on maximal velocity obtained with benzyl alcohol and 3-APADP suggest that with these substrates the hydride transfer step is rate-limiting and a pK of 6.5-7.0 may be the true pK of the acid-base catalyst, possibly a histidine.
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Liu SQ, Bhatnagar A, Srivastava SK. Bovine lens aldose reductase. pH-dependence of steady-state kinetic parameters and nucleotide binding. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74419-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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99
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Fung YC, Liu SQ, Zhou JB. Remodeling of the constitutive equation while a blood vessel remodels itself under stress. J Biomech Eng 1993; 115:453-9. [PMID: 8302025 DOI: 10.1115/1.2895523] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Changes in the mechanical properties of a blood vessel when it remodels itself under stress are reviewed. One of the recent findings about blood vessels is the rapidity of tissue remodeling when the blood pressure is changed. When the tissue structure and material composition remodel, the zero-stress state of the vessel changes. The mechanical properties change also in the remodeling process. If the elastic behavior is expressed in terms of a pseudo-elastic strain-energy function, then the constants in the function will change in the course of the remodeling. With all these changes taking place, the scope of constitutive equations broadens: it should now include a mass-and-structure growth-stress relationship as well as a stress-strain-relationship. To obtain the mass-and-structure growth-stress relationship, one must be able to determine the mechanical properties of the different layers of the vessel wall, as well as the chemical composition and morphology. For the blood vessels, new methods of mechanical testing must be introduced. A key thought is to use bending of the blood vessel wall. By bending, different layers of the vessel wall are subjected to different stresses, leading to equations that can be used to solve the inverse problem of determining the stress-strain law from measured stress and strain. In vitro and in vivo experiments and theoretical prospectives are presented.
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100
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Liu SQ, Fung YC. Material coefficients of the strain energy function of pulmonary arteries in normal and cigarette smoke-exposed rats. J Biomech 1993; 26:1261-9. [PMID: 8262988 DOI: 10.1016/0021-9290(93)90350-n] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effect of cigarette smoke on the stress-strain relationship of pulmonary arteries was studied in 2- and 3-month smoke-exposed rats. The animals were exposed to cigarette smoke in a smoke-generating system 10 times daily with one cigarette each time. The smoke density and the puffing duration and frequency of the system were regulated in accordance with reference values measured from human smokers. The mechanical properties of the pulmonary arteries about 450 microns in external diameter (at zero pressure) were determined in vitro by inflation and deflation tests. The average stress and middle-wall strain of the selected pulmonary arteries were determined on the basis of experimental data including inflation and deflation pressures during loading and unloading processes, respectively, and vessel diameter and length at various pressure levels, and vessel circumferential and longitudinal lengths at zero-stress state. A constitutive equation for the pulmonary arteries was derived from an energy function depending on circumferential and longitudinal Green's strains. The coefficients of the strain energy function of the pulmonary arteries were determined in both the smoke-exposed and control rats by fitting the experimental stress-strain data with the constitutive equation. It was found that the wall stress of the pulmonary arteries at a given strain and most of the coefficients of the strain energy function were increased in both the 2- and 3-month smoke-exposed rats in comparison with those in the corresponding controls. These results indicated that cigarette smoke induced an increase in the wall stiffness of the pulmonary arteries in the rats.
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