1751
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Abstract
Regional lymph-node (LN) lymphocytes may constitute an important defence against the spread of human melanoma beyond regional LNs. The present study was directed to clonal analysis of lymphocytes cultured either directly from the LNs or after stimulation in cultures with autologous melanoma (MLTC). T-cell clones derived from MLTC reactions had either CD4+ or CD8+ phenotypes. Inhibition studies with monoclonal antibodies (MAbs) suggested that the CD8+ cytotoxic T-cell (CTL) clones had MHC-class-I-restricted cytotoxic activity against the autologous and a proportion of HLA-class-I-compatible allogeneic melanomas. The pattern of cytotoxicity against a panel of HLA-typed melanoma cells and inhibition by (polyclonal) HLA-typing sera suggested the CD8+ CTL were restricted by HLA-A3. The CD4+ T-cell clones had weak cytotoxic activity which appeared restricted by HLA-DR2. T cells cultured from unstimulated lymphocytes were all CD4+. One of the clones exhibited cytotoxic activity against both the autologous and HLA-DR2-compatible allogeneic melanoma cells, whereas another 2 had cytotoxic activity only against a HLA-DR2-compatible allogeneic melanoma established from a primary melanoma. IL-2 production by a 4th non-cytotoxic clone had similar specificity. These results suggest that HLA-A3 and DR2 may act as restricting elements in recognition of melanoma antigens by T cells from LNs and that they may have recognized at least 2 different antigens on the melanoma cells.
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Affiliation(s)
- Q Chen
- Immunology and Oncology Unit, Newcastle Mater Misericordiae Hospital, N.S.W., Australia
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1752
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Affiliation(s)
- Q Chen
- Department of Anatomy and Cellular Biology, Tufts University Health Sciences Schools, Boston, MA 02111
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1753
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Chen Q, Linsenmayer C, Gu H, Schmid TM, Linsenmayer TF. Domains of type X collagen: alteration of cartilage matrix by fibril association and proteoglycan accumulation. J Cell Biol 1992; 117:687-94. [PMID: 1572897 PMCID: PMC2289439 DOI: 10.1083/jcb.117.3.687] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
During endochondral bone formation, hypertrophic cartilage is replaced by bone or by a marrow cavity. The matrix of hypertrophic cartilage contains at least one tissue-specific component, type X collagen. Structurally type X collagen contains both a collagenous domain and a COOH-terminal non-collagenous one. However, the function(s) of this molecule have remained largely speculative. To examine the behavior and functions of type X collagen within hypertrophic cartilage, we (Chen, Q., E. Gibney, J. M. Fitch, C. Linsenmayer, T. M. Schmid, and T. F. Linsenmayer. 1990. Proc. Natl. Acad. Sci. USA. 87:8046-8050) recently devised an in vitro system in which exogenous type X collagen rapidly (15 min to several hours) moves into non-hypertrophic cartilage. There the molecule becomes associated with preexisting cartilage collagen fibrils. In the present investigation, we find that the isolated collagenous domain of type X collagen is sufficient for its association with fibrils. Furthermore, when non-hypertrophic cartilage is incubated for a longer time (overnight) with "intact" type X collagen, the molecule is found both in the matrix and inside of the chondrocytes. The properties of the matrix of such type X collagen-infiltrated cartilage become altered. Such changes include: (a) antigenic masking of type X collagen by proteoglycans; (b) loss of the permissiveness for further infiltration by type X collagen; and (c) enhanced accumulation of proteoglycans. Some of these changes are dependent on the presence of the COOH-terminal non-collagenous domain of the molecule. In fact, the isolated collagenous domain of type X collagen appears to exert an opposite effect on proteoglycan accumulation, producing a net decrease in their accumulation, particularly of the light form(s) of proteoglycans. Certain of these matrix alterations are similar to ones that have been observed to occur in vivo. This suggests that within hypertrophic cartilage type X collagen has regulatory as well as structural functions, and that these functions are achieved specifically by its two different domains.
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Affiliation(s)
- Q Chen
- Department of Anatomy and Cellular Biology, Tufts University Health Sciences Schools, Boston, Massachusetts 02111
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1754
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Chen Q, Yu K, Holbrook NJ, Stevens JL. Activation of the growth arrest and DNA damage-inducible gene gadd 153 by nephrotoxic cysteine conjugates and dithiothreitol. J Biol Chem 1992; 267:8207-12. [PMID: 1569075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The cellular and biochemical events which transduce chemical insults into signals for increased expression of the stress-responsive gene gadd 153 were investigated using nephrotoxic cysteine conjugates. In LLC-PK1 cells, cysteine conjugate toxicity is initiated by covalent binding, but depletion of cellular thiols, an increase in cytosolic free calcium, and lipid peroxidation couple the binding to cell death (Chen, Q., Jones, T. W., Brown, P. C., and Stevens, J. L. (1990) J. Biol. Chem. 265, 21603-21611; Chen, Q., Jones, T. W., and Stevens, J. L. (1991) Toxicologist 11, 101, 1991). Three different toxic cysteine conjugates induced gadd 153 mRNA. With S-(1,2-dichlorovinyl)-L-cysteine (DCVC), the induction was both concentration and time-dependent. Preventing the metabolism of DCVC and covalent binding of DCVC-derived reactive metabolites to cellular macromolecules with the beta-lyase inhibitor (aminooxy)acetic acid blocked the induction. However, buffering free calcium with a cell permeable calcium chelator or blocking lipid peroxidation with an antioxidant did not affect the induction of gadd 153 mRNA by DCVC even though these treatments inhibit toxicity. These data suggest that covalent binding of reactive metabolites to cellular macromolecules may serve as a primary signal for the induction of gadd 153 mRNA by nephrotoxic cysteine conjugates. Interestingly, the sulfhydryl agent dithiothreitol, which was nontoxic and prevented the toxicity of DCVC, also induced an increase in gadd 153 mRNA. When both dithiothreitol and DCVC were added to cells, there were no inhibitory or additive effects on expression. Therefore, cellular thiol-disulfide status may also play a role in gadd 153 induction.
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Affiliation(s)
- Q Chen
- W. Alton Jones Cell Science Center, Lake Placid, New York 12946
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1755
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He Y, Li R, Chen Q, Lin Z, Xia D, Ma L. [Chemical studies on immunologically active polysaccharides of Ganoderma lucidum(Leyss. ex Fr.) Karst]. Zhongguo Zhong Yao Za Zhi 1992; 17:226-8, 256. [PMID: 1418551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BN3B, the polysaccharide component of the fruit of Ganoderma lucidum, has been shown to have immune activity. From BN3B four homogeneous polysaccharides were separated and purified. Chemical studies on the main components BN3B1 and BN3B3 indicated that BM3B1 contained only glucose and should be a glucan containing beta-(1----6) and (1----3)glycoside bonds and that BN3B3 was an arabinogalactan containing beta-(1----6) and (1----3)glycoside bonds.
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Affiliation(s)
- Y He
- School of Pharmacy, Beijing Medical University
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1756
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Abstract
SV40-transformed green monkey kidney (COS-1) cells were transfected with expression plasmids that contained either the structural gene or cDNA for surfactant protein A (SP-A), a major protein of rabbit lung surfactant. The transfected COS-1 cells synthesized several isoforms of SP-A that were found to be less acidic than those produced in rabbit lung tissue. SP-A species with apparent molecular weight (M(r)) approximately equal to 29,000-33,000 were detected in the transfected cells, whereas glycosylated forms with apparent M(r) approximately equal to 33,000-38,000 were detectable only in the culture medium. Analysis of transfected cells by indirect immunofluorescence revealed that SP-A was localized in punctate bodies throughout the cytoplasm. Expressed SP-A was not detectable on the cell surface nor was there evidence that secreted SP-A was endocytosed by COS-1 cells. After subcellular fractionation of the transfected COS-1 cells, SP-A was found to be localized predominantly in the 5,000- and 18,000-g pellet fractions; little or no immunoreactive SP-A was detectable in cytosolic fractions. Treatment of transfected cells with the glycosylation inhibitor tunicamycin prevented secretion of SP-A into the medium, suggesting a role of glycosylation in secretion of SP-A. On the other hand, treatment of transfected cells with inhibitors of proline hydroxylation, which may cause destabilization of the collagen-like domain of SP-A, reduced but did not prevent secretion of SP-A into the culture medium.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J L Alcorn
- Department of Biochemistry, Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas 75235
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1757
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Abstract
Force development and fura-2 fluorescence were simultaneously measured in the rabbit inferior vena cava. Discharging SR Ca2+ with either caffeine or norepinephrine prior to stimulation of Ca2+ influx induced a delay of 30-70 s between the intracellular Ca2+ signal and development of force. This delay was abolished by the application of caffeine. These data support the superficial buffer barrier hypothesis, which holds that Ca2+ entry from the extracellular space proceeds via a restricted cytoplasmic region between the inner plasmalemmal surface and the peripheral sarcoplasmic reticulum (SR). Ca2+ accumulation by this SR fraction appears to be able to delay Ca2+ entry into the deeper myoplasm where it activates the myofilaments. Caffeine and thapsigargin elevated the steady-state [Ca2+]i, suggesting a contribution by the SR Ca2+ pump to Ca2+ extrusion from the cells. Norepinephrine enhanced myofilament Ca2+ sensitivity, while caffeine decreased it.
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Affiliation(s)
- Q Chen
- Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, FL 33101
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1758
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Chen Q, Yu K, Holbrook N, Stevens J. Activation of the growth arrest and DNA damage-inducible gene gadd 153 by nephrotoxic cysteine conjugates and dithiothreitol. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42428-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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1759
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Chen Q, Sun P, Prigione I, Xie H, Ferrini S. Targeting of «T» Lymphocytes against Human Hepatoma Cells by a Bispecific Monoclonal Antibody: Role of Different Lymphocyte Subsets. Tumori 1992; 78:79-86. [PMID: 1326141 DOI: 10.1177/030089169207800204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In an attempt to construct bispecific monoclonal antibodies (bimAbs) able to target cytotoxic T lymphocytes against human hepatoma cells, an HGPRT-deficient mutant of the Hepama-6 hybridoma, which produces an antihuman-hepatoma mAb, was directly fused with splenocytes from Balb/C mice immunized by a polyclonal cytotoxic T-cell line. Hybrid hybridomas were selected in HAT medium, and their supernatants were directly screened for the ability to induce IL-2-cultured cytotoxic T lymphocytes to kill hepatoma cells in a 51Cr-release assay. The selected hybrid hybridoma, termed DQ-33, secretes a bimAb, which reacts with a CD3-associated determinant. When resting peripheral-blood lymphocytes were used as effector cells, virtually no cytolytic activity could be induced by DQ-33, whereas phytohemagglutinin-activated lymphocytes that had been expanded in vitro in IL-2-containing medium could be efficiently targeted against hepatoma cells. Targeting by DQ-33 bimAb was analyzed on different subsets of IL-2-cultured lymphocytes. It was evident that CD+4–8+ TCRα/β+ and CD3+4–8-TCRγ/δ+ lymphocytes were efficiently induced by bimAb to lyse human hepatoma cells, whereas no induction of cytolysis could be observed when CD3 + 4+8-TCRα/β+ cells were used as effectors. DQ-33 bimAb was also able to induce lymphokine secretion (IL-2, GM-CSF and TNF-α) by all the different subsets of lymphocytes analyzed in the presence of target cells expressing the relevant antigen, independent of the expression of cytolytic activity.
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Affiliation(s)
- Q Chen
- Shanghai Institute of Cell Biology, Chinese Academy of Science
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1760
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Fu Y, Chen Q, Willander M, Chao KA. Quasi-two-dimensional electron system in a GaAs/AlxGa1-xAs heterojunction. Phys Rev B Condens Matter 1992; 45:6709-6714. [PMID: 10000432 DOI: 10.1103/physrevb.45.6709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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1761
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Huang G, Chen Q. [A preliminary study of the chord and specific time constants in 342 healthy children]. Hua Xi Yi Ke Da Xue Xue Bao 1992; 23:49-52. [PMID: 1398624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Using Knudson's method, the chord time constant, tau ch, tau ch75, tau ch50, tau ch25, and specific time constant, S tau, 1/V75, 1/V50, 1/V25, at high, middle and low lung volumes were calculated from V75, V50 and V25 of the MEFV curves measured previously from 342 healthy children of 3-6 years of age in a nursery. The multiple stepwise regression equation were built with age, height and FVC as independent variables by the IBM-XT/PC computer. The result showed that the S tau corrected by volume from tau ch could reflect the time required for change of unit lung volume more precisely than tau ch owing to the elimination of the influence of lung volume. The S tau was shortened with the increase of age, and was negatively correlate with age and FVC. These facts reflected the growth of lung elastic pressure (PLel) and airway conductance (Gaw) with the increase of age. The prolongation of S tau with the decay of lung volume just reflected the decrease of PLel and Gaw with the decay of lung volume. No regular changes of tau h were observed with age and lung volume. Probably, it was concerned with the complexity of factors affecting the tau ch.
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1762
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Chen Q, Ng K. Gap anisotropy of Bi2Sr2CaCu2O8 measured by low-temperature scanning tunneling microscopy. Phys Rev B Condens Matter 1992; 45:2569-2572. [PMID: 10001799 DOI: 10.1103/physrevb.45.2569] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1763
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1764
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Shen Y, Zhou Y, Chen Q, Ge Y. Digital subtraction angiography in the preoperative diagnosis of congenital heart disease. Tex Heart Inst J 1992; 19:284-7. [PMID: 15227455 PMCID: PMC325033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
From December of 1986 through February of 1990, digital subtraction angiography was performed on 156 patients, and specific diagnoses of congenital heart disease were made on the basis of information gathered by this imaging technique, supplemented by the physical examination. No other imaging techniques were used, for this was a prospective study designed to determine the accuracy of digital subtraction angiography alone in the diagnosis of congenital heart disease. When 80 of these 156 patients underwent subsequent operation, 75 were shown to have been diagnosed correctly, for an accuracy rate of 93.75%. Two patients died, for a mortality rate of 2.5%. The diagnostic value of digital subtraction angiography is discussed, as well as the compensative management of its artifacts.
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Affiliation(s)
- Y Shen
- The Department of Cardiothoracic Surgery, Tongji Hospital, Tongji Medical University, Wuhan, People's Republic of China
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1765
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Abstract
Transferrin subtypes were determined by isoelectric focussing (IEF) in a total of 2,121 individuals from 11 South China minority populations. The C1, C2 and DCHI alleles were present in all the populations; B alleles were lacking, C4 was found in 3 populations and C3 in 6. C2 and C4 allele frequencies are notable in these minority groups. The frequency of the C2 allele was higher (0.25-0.38) than that of Han Chinese (0.18-0.25). In Bai the C2 frequency was as high as 0.38. The C4 allele was present at a low frequency (less than 0.01), which suggests that this allele probably existed in the ancestral Mongoloid population at a low frequency and increased in frequency in Amerindians due to genetic drift or other factors.
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Affiliation(s)
- J X Chen
- Laboratory of Blood Typing and Serology, Chinese Academy of Medical Sciences, Chengdu
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1766
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Chen Q, Klemm N, Jeng IM. Irreversible inactivation of diacylglycerol kinase-II requires a mediator. Biochem Int 1991; 25:775-81. [PMID: 1667722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cytosolic diacylglycerol kinase was irreversibly inactivated by 5'-AMP since the enzyme remained less active after the removal of 5'-AMP by P-10 gel chromatography. The inactivation was time-dependent, suggesting the involvement of a covalent bond modification. A reconstitution experiment detected a rat brain cytosolic mediator for the effect of 5'-AMP. A protein kinase rich fraction prepared from rat liver was also capable of restoring the sensitivity of diacylglycerol kinase-II to 5'-AMP. We propose that 5'-AMP-activated protein kinase is the mediator which inactivates diacylglycerol kinase-II, possibly by phosphorylation.
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Affiliation(s)
- Q Chen
- Department of Biochemistry, University of Missouri, Columbia 65212
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1767
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Takanashi Y, Chopp M, Levine SR, Kim J, Moran JE, Tepley N, Chen Q, Barkley GL, Welch KM. Magnetic fields associated with anoxic depolarization in anesthetized rats. Brain Res 1991; 562:13-6. [PMID: 1799865 DOI: 10.1016/0006-8993(91)91180-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have performed simultaneous measurements of the DC-magnetoencephalogram (DC-MEG) and DC-electrocorticogram (DC-ECoG) in rats (n = 6) subjected to 90 s of reversible anoxia. The onset of major shifts of electric and magnetic signals occurred at 52 +/- 18 (S.D.) and 68 +/- 14 (S.D.), respectively, and reached a peak at 83 +/- 27 and 102 +/- 19 (S.D.) s, respectively, after termination of mechanical ventilation. DC-ECoG signal deflections were always associated with DC-MEG deflections. The time of onset and peak signals in both DC-MEG and DC-ECoG changes caused by asphyxia were highly correlated (r + 0.83, 0.94; P less than 0.05, 0.001; respectively). Our observations suggest that the non-invasive technique of DC-MEG is reliable and may provide insight into the mechanisms of anoxic cerebral depolarization.
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Affiliation(s)
- Y Takanashi
- Department of Neurology, Henry Ford Hospital, Detroit, MI 48202
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1768
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Huang G, Chen Q. [Determination of the partial mean transit time with "convenient calculation" in young children]. Hua Xi Yi Ke Da Xue Xue Bao 1991; 22:391-3. [PMID: 1814819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A "convenient calculation" of MTTp = 0.1 FVC/2 Vp was derived from the principle of Jordanoglou to measure the partial mean transit time (MTTp). It was used to calculate the MTTp from the maximal expiratory flow volume (MEFV) curve of 342 healthy young children. The multiple regression equations were built with age, height and FVC as independent variables. The result showed that the MTTp of all children were elongated with the decay of lung volume with a similar rule as in the old, middle-aged and young people. No regular changes of MTTp in age groups were noticed. The regression equations showed that the MTTp of boys were positively correlated with FVC; while those of girls were negatively correlated with age; besides, MTT20-30% and MTT70-80% were positively correlated with FVC. The age and FVC just had the opposite effects so that little regular changes of MTTp occurred in the age groups.
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1769
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Chen Q, Vierling E. Analysis of conserved domains identifies a unique structural feature of a chloroplast heat shock protein. Mol Gen Genet 1991; 228:328. [PMID: 1886617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Q Chen
- Department of Biochemistry, University of Arizona, Tucson 85721
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1770
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Abstract
Almost 30% of patients with T-cell acute lymphoblastic leukemia (T-ALL) bear structural alterations of tal-1, a presumptive proto-oncogene that encodes sequences homologous to the helix-loop-helix (HLH) DNA-binding and dimerization domain. Analysis of the tal-1 gene product reveals that its HLH domain mediates protein-protein interactions with either of the ubiquitously expressed HLH proteins E47 and E12. The resultant tal-1/E47 and tal-1/E12 heterodimers specifically recognize the E-box DNA sequence motif found in eucaryotic transcriptional enhancers. Hence, the tal-1 protein shares biochemical properties with other tissue-specific HLH proteins that control cell type determination during myogenesis (e.g., MyoD1) and neurogenesis (e.g., achaete-scute). The data suggest that HLH heterodimers involving tal-1 may function in vivo as transcriptional regulatory factors that influence cell type determination during hematopoietic development.
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Affiliation(s)
- H L Hsu
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048
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1771
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Ferrini S, Prigione I, Miotti S, Ciccone E, Cantoni C, Chen Q, Colnaghi MI, Moretta L. Bispecific monoclonal antibodies directed to CD16 and to a tumor-associated antigen induce target-cell lysis by resting NK cells and by a subset of NK clones. Int J Cancer 1991; 48:227-33. [PMID: 1826900 DOI: 10.1002/ijc.2910480213] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
CD16 surface antigens represent activatory molecules in CD3-16+ NK cells. In order to target NK cells against relatively NK-resistant ovarian carcinomas, we used an anti-CD16 monoclonal antibody (MAb) (VD4), together with an anti-ovarian carcinoma-associated antigen (MOV19), to construct biMAbs. To this end, hybrid hybridomas were generated by fusing a TK-deficient VD4 hybridoma mutant with a HGPRT-deficient MOV19 hybrid. Supernatants from hybrid hybridomas that had been selected in HAT medium were screened for their ability to induce a CD3-16+ NK clone to lyse an MOV19+ ovarian carcinoma cell line in a 4-hr 51Cr-release assay. The NMB.45 hybrid hybridoma secreted a biMAb which triggered lysis of MOV19+ but not of MOV19- target cells. Some degree of target cell lysis was also observed with MOV19 MAb (due to ADCC mechanisms), while the VD4 MAb was ineffective. HPLC fractionation of MAbs secreted by the hybrid hybridoma made it possible to identify 4 different peaks, one of which appeared to contain functional biMAb molecules. HPLC-purified biMAb (100 ng/ml) induced resting PBL to lyse the "NK-resistant" IGROVI ovarian carcinoma cell line. Fresh MOV19+ tumor cells were also lysed, although with lower efficiency. When IL-2-activated lymphocytes were used as a source of effectors, biMAb caused only minor increases in the IL-2-induced cytolytic activity. Further analyses of the effect of biMAb were performed at the clonal level. Among CD3-16+ NK cell clones, a clear enhancing effect could be observed only in GL183+ but not in GL183- clones. In CD3+ cytotoxic clones a triggering effect could be detected in one out of 4 TCR gamma/delta+ clones but not in TCR alpha/beta+ clones.
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MESH Headings
- Antibodies, Monoclonal/biosynthesis
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/isolation & purification
- Antigens, CD/immunology
- Antigens, Differentiation/immunology
- Antigens, Neoplasm/immunology
- Cell Fusion
- Chromatography, High Pressure Liquid
- Clone Cells
- Cytotoxicity, Immunologic/immunology
- Female
- Fluorescent Antibody Technique
- Humans
- Hybridomas/immunology
- Killer Cells, Natural/immunology
- Ovarian Neoplasms/immunology
- Receptors, Fc/immunology
- Receptors, IgG
- T-Lymphocytes/immunology
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Affiliation(s)
- S Ferrini
- Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
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1772
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Chen Q, Florén CH, Nilsson A, Infante R. Regulation of chylomicron remnant uptake in the human hepatoma cell-line Hep G2. Role of the low-density lipoprotein receptor. Biochim Biophys Acta 1991; 1083:173-8. [PMID: 1645203 DOI: 10.1016/0005-2760(91)90039-k] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Uptake and degradation of chylomicron remnants by the human hepatoma cell line Hep G2 was studied. Mesenteric lymph was collected from rats and injected into hepatectomized rats to obtain chylomicron remnants. This remnant preparation was taken up and catabolized by Hep G2 cells. The uptake process was dependent on cell growth and was regulated by compactin (a HMG-CoA reductase inhibitor) which suppresses cholesterol synthesis and by mevalonolactone, which enhances cholesterol synthesis. A monoclonal anti LDL receptor antibody blocked binding of chylomicron remnants to Hep G2 cells to a degree, which was comparable to but generally lower than the suppression of low-density lipoprotein binding. The results thus indicate that in Hep G2 cells, chylomicron remnant uptake is regulated, similarly to low-density lipoprotein uptake and that a significant part of the remnant uptake is mediated through the LDL receptor.
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Affiliation(s)
- Q Chen
- Research Department 2, University Hospital, Lund, Sweden
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1773
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Chen Q, Boss WF. Neomycin inhibits the phosphatidylinositol monophosphate and phosphatidylinositol bisphosphate stimulation of plasma membrane ATPase activity. Plant Physiol 1991; 96:340-3. [PMID: 16668179 PMCID: PMC1080759 DOI: 10.1104/pp.96.1.340] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The inositol phospholipids, phosphatidylinositol monophosphate (PIP) and phosphatidylinositol bisphosphate (PIP(2)), have been shown to increase the vanadate-sensitive ATPase activity of plant plasma membranes (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301). In this paper, we show the effect of various concentrations of phosphatidyinositol, PIP, and PIP(2) on the plasma membrane vanadate-sensitive ATPase activity. PIP and PIP(2) at concentrations of 10 nanomoles per 30 microgram membrane protein per milliliter of reaction mixture caused a twofold and 1.8-fold increase in the ATPase activity, respectively. The effect of these negatively charged phospholipids on the ATPase activity was inhibited by adding the positively charged aminoglycoside, neomycin. Neomycin did not affect the endogenous plasma membrane ATPase activity in the absence of exogenous lipids.
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Affiliation(s)
- Q Chen
- Department of Botany, North Carolina State University, Raleigh, North Carolina 27695-7612
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1774
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Abstract
A low molecular weight heat shock protein which localizes to chloroplasts has been identified in several plant species. This protein belongs to a eukaryotic superfamily of small HSPs, all of which contain a conserved carboxyl-terminal domain. To investigate further the structure of this HSP, we isolated and sequenced cDNA clones for the chloroplast LMW HSPs from Petunia hybrida and Arabidopsis thaliana. The cloning of chloroplast HSPs from these two species enabled us to compare the amino acid sequences of this protein from plant species (petunia, Arabidopsis, pea, soybean and maize) that represent evolutionarily divergent taxonomic subclasses. Three conserved regions were identified, which are designated as regions I, II and III. Regions I and II are also shared by cytoplasmic LMW HSPs and therefore are likely to have functional roles common to all eukaryotic LMW HSPs. In contrast, consensus region III is not found in other LMW HSPs. Secondary structure analysis predicts that this region forms an amphipathic alpha-helix with high conservation of methionine residues on the hydrophobic face and 100% conservation of residues on the hydrophilic face. This structure is similar to three helices, termed "methionine bristles", which are found in a methionine-rich domain of a 54 kDa protein component of signal recognition particle (SRP54). The conservation of regions I and II among LMW cytoplasmic and chloroplast HSPs suggests that these HSPs perform related functions in different cellular compartments. However, identification of the methionine bristle domain suggests that chloroplast HSPs also have unique functions or substrates within the special environment of the chloroplast or other plastids.
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Affiliation(s)
- Q Chen
- Department of Biochemistry, University of Arizona, Tucson 85721
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1775
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Cai HJ, Xie CL, Chen Q, Chen XY, Chen YH. The relationship between hepatic low-density lipoprotein receptor activity and serum cholesterol level in the human fetus. Hepatology 1991; 13:852-7. [PMID: 2029989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
We found that the binding of 125I-low-density lipoprotein to fetal liver low-density lipoprotein receptor rose progressively with the increase in fetal age. During this period, total cholesterol and low-density lipoprotein-cholesterol levels in fetal serum declined significantly. The correlation coefficients between fetal age and concentration of serum total cholesterol and low-density lipoprotein cholesterol were -0.80 (p less than 0.001) and -0.77 (p less than 0.001), respectively. A significant inverse correlation also existed between the liver low-density lipoprotein receptor activity and the serum total cholesterol (r = -0.96, p less than 0.001) and low-density lipoprotein cholesterol (r = -0.95, p less than 0.001) but not high-density lipoprotein cholesterol. It is suggested that the low-density lipoprotein receptors in human fetal liver may play a key role in the regulation of the serum cholesterol levels during gestation.
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Affiliation(s)
- H J Cai
- Department of Pathophysiology, Nanjing Medical College, People's Republic of China
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1776
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Chen Q, Zheng P, Zhang ZN. [Physiological significance of erythrocyte deformability and its influential factors]. Sheng Li Ke Xue Jin Zhan 1991; 22:142-6. [PMID: 1796260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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1777
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Chen Q, Xie Y, Chai H. [Effects of SC1001-sodium on hippocampal kindled seizures by coriaria lactone in rabbits]. Hua Xi Yi Ke Da Xue Xue Bao 1991; 22:43-5. [PMID: 1774035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Healthy rabbits weighing 1.7-2.4 kg were used. According to Sawyer's atlas the stainless steel cannula and recording electrode were implanted into the left hippocampus of each animal. The kindling experiments were started one week after the surgical operation. For kindling, all animals received injection of 2 microliters of diluted solution containing 0.55 or 0.32 microgram of coriaria lactone (CL) every second day, through the single stainless steel cannula previously implanted in the hippocampus. Hippocampal EEG of all the animals was recorded by telemetric method and the behavior of them was observed at the same time. Eighteen fully kindled rabbits were separated into three groups. The SC1001 Na group of six rabbits was treated with SC1001 Na (100 mg/kg, i.m.), the PB Na group (six rabbits) received phenobarbital Na (30 mg/kg, i.m.), and the control group of six was treated with placebo (normal saline, i.m., in the same volume as that of the SC1001 Na injection); injections were administered once a day for two courses of treatment (one course of treatment was 1 week). The results of the experiment indicated that SC1001 Na (100 mg/kg) had certain effects on hippocampal kindled seizures induced by CL, but its curative effects were not more notable than those of PB Na (30 mg/kg).
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1778
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Presti JC, Rao PH, Chen Q, Reuter VE, Li FP, Fair WR, Jhanwar SC. Histopathological, cytogenetic, and molecular characterization of renal cortical tumors. Cancer Res 1991; 51:1544-52. [PMID: 1671759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We used cytogenetic and restriction fragment length polymorphism (RFLP) analysis methods to define genetic alterations and also correlate the changes with histopathology in renal cortical tumors. The study series is comprised of 50 renal tumors in 4 histological categories: (a) clear cell, nonpapillary, renal cell carcinoma (RCC) (n = 32); (b) nonclear cell, nonpapillary RCC (n = 10); (c) papillary RCC (n = 3); and (d) oncocytic tumors (n = 5). Successful karyotypes were obtained from 28 tumors (56%), of which 17 (61%) were abnormal. Abnormalities of chromosome 3p were seen in 9 tumors, which included unbalanced translocations and terminal or interstitial deletions. Abnormalities of chromosome 5 were identified in 11 tumors, 8 of which were due to unbalanced translocations between 3p and 5q, resulting in an extra copy for the region 5q22----ter. In addition, trisomy or tetrasomy of chromosome 17 was seen in 6 (5 with normal chromosome 3 and one with 3p deletion), trisomy or more copies of chromosome 7 in 8 (4 with 3p deletion, 2 with trisomy or tetrasomy 17, and 2 with trisomy alone), and trisomy 12 in 3 (all with trisomy 17) tumors. Furthermore, relative deficiency of chromosome 17p was seen in 3 (all with deletion 3p) and chromosome 18 in 4 (all with deletion 3p) tumors. RFLP analysis with four chromosome 3 specific probes detected 3p deletions in 19 tumors with the most common breakpoint located between 3p14-21. The 19 3p deletions detected by RFLP included tumors that also showed rearrangement of 3p by cytogenetics (n = 4) and those that showed normal karyotypes (n = 3) in addition to cytogenetic failures (n = 12). Deletions of 17p were seen in 5 of 31 informative cases. Thus, deletions of 3p were seen in a total of 24 tumors by cytogenetic and/or RFLP analysis, 21 of which were clear cell, nonpapillary RCC, whereas 3 had a minor clear-cell component. Oncocytic and nonclear, nonpapillary tumors, on the other hand, did not demonstrate 3p deletions by either technique, whereas trisomy 17 was seen in 3 of the 3 papillary tumors. The loss of alleles from chromosome 17p and 18 and an increased dosage of gene or genes on chromosomes 5q and 7 as seen in high-stage tumors of various histological subtypes may be associated with progression of disease.
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Affiliation(s)
- J C Presti
- Division of Urology, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
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1779
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Chen Q, Stevens JL. Inhibition of iodoacetamide and t-butylhydroperoxide toxicity in LLC-PK1 cells by antioxidants: a role for lipid peroxidation in alkylation induced cytotoxicity. Arch Biochem Biophys 1991; 284:422-30. [PMID: 1989526 DOI: 10.1016/0003-9861(91)90318-d] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previously we reported that thiol depletion and lipid peroxidation were associated with the cytotoxicity of nephrotoxic cysteine S-conjugates, a group of toxins which kill LLC-PK1 cells after metabolic activation and covalent binding. To determine if this is a general mechanism of cytotoxicity in these cells, we compared the effect of antioxidants, an iron chelator, and a thiol reducing agent on the toxicity of an alkylating agent, iodoacetamide (IDAM), and an organic peroxidant, t-butylhydroperoxide (TBHP). IDAM or TBHP toxicity was concentration (0.01 to 1.0 mM) and time (1 to 6 h) dependent. Both toxins caused lipid peroxidation which occurred prior to cell death as determined by leakage of lactate dehydrogenase (LDH). The alkylating agent IDAM bound to cellular macromolecules and depleted cellular non-protein thiols almost completely by 1 h, while LDH release occurred first at 2 to 3 h. The toxicity of IDAM and TBHP was inhibited by the antioxidants DPPD, BHA, BHQ, PGA, and BHT and the iron chelator deferoxamine. However, DPPD blocked TBHP- and IDAM-induced lipid peroxidation and toxicity without affecting binding and depletion of cellular nonprotein thiols. Furthermore, the thiol reducing agent dithiothreitol was able to block lipid peroxidation and toxicity. Therefore it is possible that with an alkylating agent, depletion of cellular nonprotein thiols cooperates with covalent binding and contributes to lipid peroxidation and cell death. There appear to be common elements in the toxicity of alkylating agents and organic peroxidants in LLC-PK1 cells.
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Affiliation(s)
- Q Chen
- W. Alton Jones Cell Science Center, Lake Placid, New York 12946
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1780
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Abstract
The role of basic fibroblast growth factor (bFGF) in signaling the development of the neuromuscular junction was examined. Beads coated with bFGF induced the formation of acetylcholine receptor (AChR) clusters in cultured Xenopus myotomal muscle cells. Tyrphostin, a tyrosine kinase inhibitor, abolished AChR clustering induced by bFGF beads, suggesting a role of tyrosine kinase activation in AChR clustering. Using specific antibodies, we demonstrated the presence of both bFGF and its receptor in the myotomal muscle in vivo during the period of neuromuscular connection. However, similar tissue from older animals with mature neuromuscular junctions showed an apparently truncated form of the bFGF receptor. These data suggest that bFGF may play a role in signaling synaptogenesis in skeletal muscle.
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Affiliation(s)
- H B Peng
- Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599
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1781
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Fraissard J, Gedeon A, Chen Q, Ito T. 129Xe NMR study of intra- and inter- crystallite diffusion of cations in faujasite zeolites. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/s0167-2991(08)61601-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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1782
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Chen Q. [Effect of pulsed electromagnetic field on orthodontic tooth movement through transmission electromicroscopy]. Zhonghua Kou Qiang Yi Xue Za Zhi 1991; 26:7-10, 61. [PMID: 2032488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This experiment is to observe the effect of pulsed electromagnetic field (PEMF) on orthodontic tooth movement of guinea pigs through transmission electron microscope (TEM). 14-days observations indicate that PEMF could accelerate the rate of orthodontic tooth movement as a result of the increase in quantity of active cell without changing the ultrastructures of cells and have no unfavorable effects on periodontal tissues.
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Affiliation(s)
- Q Chen
- School of Stomatology, Shanghai Second Medical University
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1783
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Affiliation(s)
- H B Peng
- Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599
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1784
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Chen Q, Jones TW, Brown PC, Stevens JL. The mechanism of cysteine conjugate cytotoxicity in renal epithelial cells. Covalent binding leads to thiol depletion and lipid peroxidation. J Biol Chem 1990; 265:21603-11. [PMID: 2254317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nephrotoxic cysteine conjugates kill cells after they are metabolized by the enzyme cysteine conjugate beta-lyase to reactive fragments which bind to cellular macromolecules. We have investigated the cellular events which occur after the binding and lead ultimately to cell death in renal epithelial cells. Using S-(1,2-dichlorovinyl)-L-cysteine (DCVC) as a model conjugate, we found that the phenolic antioxidants N,N'-diphenyl-p-phenylenediamine (DPPD), butylated hydroxyanisole, butylated hydroxytoluene, propyl galate, and butylated hydroxyquinone, and the iron chelator deferoxamine inhibited the cytotoxicity significantly. Among the five antioxidants, DPPD was most potent. DPPD blocked DCVC toxicity over an extended time period, and the rescued cells remained functional as measured by protein synthetic activity. DPPD was able to block the toxicity of two other toxic cysteine conjugates S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine and S-(1,1,2,2-tetrafluoroethyl)-L-cysteine. In addition to LLC-PK1 cells, DPPD also protected freshly isolated rat kidney epithelial cells in suspension and in primary culture. In suspension cells, DPPD was effective at low doses of DCVC (25-50 microM) but not at high concentrations (250-500 microM). DPPD inhibition was not due to an inactivation of beta-lyase or a decrease in the binding of [35S]DCVC metabolites to cellular macromolecules and occurred at a step after the activation of the toxins. During DCVC treatment, lipid peroxidation products were detectable prior to cell death. DPPD blocked lipid peroxidation over the whole time course. Depletion of nonprotein thiols also occurred prior to cell death. DPPD did not prevent the loss of nonprotein thiols. However, the sulfhydryl-reducing agent DTT blocked lipid peroxidation and toxicity at a step after the activation of DCVC. Therefore, it appears that cysteine conjugates kill renal epithelial cells by a combination of covalent binding, depletion of nonprotein thiols, and lipid peroxidation.
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Affiliation(s)
- Q Chen
- W. Alton Jones Cell Science Center, Lake Placid, New York 12946
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1785
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1786
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Chen Q, Jones TW, Brown PC, Stevens JL. The mechanism of cysteine conjugate cytotoxicity in renal epithelial cells. Covalent binding leads to thiol depletion and lipid peroxidation. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)45783-3] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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1787
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Chen Q, Boss WF. Short-term treatment with cell wall degrading enzymes increases the activity of the inositol phospholipid kinases and the vanadate-sensitive ATPase of carrot cells. Plant Physiol 1990; 94:1820-9. [PMID: 16667922 PMCID: PMC1077459 DOI: 10.1104/pp.94.4.1820] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Treating carrot (Daucus carota L.) suspension culture cells with a mixture of cell wall degrading enzymes, Driselase, resulted in an increase in the percentage of [(3)H]phosphatidylinositol bisphosphate. Analysis of the lipid kinase activities in the isolated plasma membranes after whole cell treatment indicated that treatment with Driselase (2% weight/volume; the equivalent of 340 units per milliliter of hemicellulase and 400 units per milliliter of cellulase activity) or treatment with hemicellulase (31.7% weight/volume, 20.7 units per milliliter) resulted in an increase in the inositol phospholipid kinase activity. However, treatment with cellulase alone had no effect at 0.5% (weight/volume, 17.2 units per milliliter) or inhibited the kinase activity at 1% (weight/volume, 34.4 units per milliliter). The active stimulus in Driselase was heat sensitive. The plasma membrane vanadate-sensitive ATPase activity also increased when the cells were treated with Driselase. A time course study indicated that both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase responded to as little as 5 seconds of treatment with 2% Driselase. However, at the lowest concentration of Driselase (0.04%, weight/volume) that resulted in an increase in inositol phospholipid kinase activity, the ATPase activity was not affected. Because inositol phospholipids have been shown to activate the vanadate-sensitive ATPase from plants (AR Memon, Q Chen, WF Boss [1989] Biochem Biophys Res Commun 162: 1295-1301), a stimulus-response pathway involving both the inositol phospholipid kinases and the plasma membrane vanadate-sensitive ATPase activity is discussed.
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Affiliation(s)
- Q Chen
- Department of Botany, North Carolina State University, Raleigh, North Carolina 27695-7612
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1788
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Wang W, Chen Q, Dai W. [Microsurgery to treat lesions in or near the eyeball wall]. Yan Ke Xue Bao 1990; 6:84-7. [PMID: 2289581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Four sub-retinal cysticerci and 12 cases of nonmagnetic intraocular foreign bodies near the eyeball wall were first localized with indirect ophthalmoscopy and then removed successfully under surgical microscopy. Three layers, ie white sclera, black supra-choroid pigment and light brown choroidal tissue with white vascular pattern were encountered before reaching the sub-retinal larval. The ischemic appearance of the choroid probably was caused by compression of the larval underneath it. Intraocular foreign bodies usually appeared in the wound accompanied by liquified vitreous as soon as the incision was made. If intraocular inflammation exist, foreign body can be found within the pus or dense exudates.
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Affiliation(s)
- W Wang
- Eye and ENT Hospital, Shanghai Medical University, China
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1789
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Chen Q, Yang CY, Tsan JT, Xia Y, Ragab AH, Peiper SC, Carroll A, Baer R. Coding sequences of the tal-1 gene are disrupted by chromosome translocation in human T cell leukemia. J Exp Med 1990; 172:1403-8. [PMID: 2230650 PMCID: PMC2188666 DOI: 10.1084/jem.172.5.1403] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The tal-1 proto-oncogene encodes a helix-loop-helix DNA-binding protein that has been implicated in the formation of T cell acute lymphoblastic leukemia (T-ALL). Patients with T-ALL harbor structural rearrangements of tal-1 that result from either local DNA deletion or t(1;14)(p34;q11) chromosome translocation. By analyzing t(1;14)(p34;q11) chromosomes from a series of patients, we have now identified a discrete region of tal-1 wherein most of the translocation breakpoints occur. Moreover, mapping of tal-1 genomic DNA revealed that coding exons are situated on both sides of the t(1;14)(p34;q11) major breakpoint region. Hence, the translocated allele of tal-1 is truncated in a manner that reduces its amino acid coding potential.
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Affiliation(s)
- Q Chen
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235
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1790
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Abstract
The metabolic response of normal rat brain to photodynamic therapy (PDT) was studied over a 1 week interval using in vivo 31P-NMR spectroscopy. Rats injected with 12.5 mg/kg Photofrin II were submitted to brain photoactivation 48 h after drug administration with either 140 or 70 J/cm2 light (630 +/- 1 nm) from an Argon dye laser. Control studies, animals not given drug or light, animals submitted only to brain illumination without drug, and animals given drug but no light, were also performed. The data revealed a transient metabolic degradation; a decrease in the ratio of beta-nucleotriphosphate to inorganic phosphate (P less than 0.001) at 24 h after PDT treatment was followed by a return to pretreatment spectral values. Brain tissue alkalosis was also noted, with significant (P less than 0.05) differences in brain tissue pH detected at 72 h post treatment between 70 J/cm2 PDT vs control studies and at 1 week post treatment between 140 J/cm2 vs 70 J/cm2, 140 J/cm2 vs no light-no drug and 140 J/cm2 vs drug only. The data suggest that there is no difinitive metabolic marker from 31P-NMR spectroscopy that can identify necrotic brain tissue caused by PDT. Phosphorus-31 NMR data are also presented which suggest that PDT damage to brain is not solely the result of microvascular occlusion causing ischemic necrosis.
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Affiliation(s)
- M Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, MI 48202
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1791
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Barros H, Chen Q, Florén CH, Nilsson A. Arachidonic acid absorption in human jejunum in organ culture: effects of ethanol. Eur J Clin Invest 1990; 20:506-10. [PMID: 2124981 DOI: 10.1111/j.1365-2362.1990.tb01893.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human jejunal tissue obtained by peroral biopsy was cultured in control medium and in medium containing 100 mmol l-1 ethanol. Subsequently, the incorporation and metabolism of [3H]-arachidonic and [14C]-linoleic acid were evaluated. Of the two fatty acids a significantly higher amount of [3H]-arachidonic acid was incorporated into phospholipids and more [14C]-linoleic acid was incorporated into triacylglycerols. This preferential distribution of the labelled fatty acids was not affected by ethanol, but when ethanol was present in the tissue culture medium, there was a significant decrease in the incorporation of both fatty acids into tissue phospholipids. The study thus shows that ethanol in moderate concentrations can affect human jejunal absorption and metabolism of polyenoic fatty acids, contributing to a decrease in the amount of eicosanoid precursors available in jejunal tissue.
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Affiliation(s)
- H Barros
- Research Department 2, University Hospital, Lund, Sweden
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1792
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Chen Q. [Nursing care in patients with abdominal tumor with hyperthermia]. Zhonghua Hu Li Za Zhi 1990; 25:515-7. [PMID: 2261676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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1793
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Brown L, Cheng JT, Chen Q, Siciliano MJ, Crist W, Buchanan G, Baer R. Site-specific recombination of the tal-1 gene is a common occurrence in human T cell leukemia. EMBO J 1990; 9:3343-51. [PMID: 2209547 PMCID: PMC552072 DOI: 10.1002/j.1460-2075.1990.tb07535.x] [Citation(s) in RCA: 181] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The tal-1 gene is altered as a consequence of the t(1;14) (p32;q11) chromosome translocation observed in 3% of patients with T cell acute lymphoblastic leukemia (T-ALL). tal-1 encodes a helix-loop-helix (HLH) domain, a DNA binding and dimerization motif found in a number of proteins involved in cell growth and differentiation. We now report that an additional 25% of T-ALL patients bear tal-1 gene rearrangements that are not detected by karyotype analysis. These rearrangements result from a precise 90 kb deletion (designated tald) that arises independently in different patients by site-specific DNA recombination. Since the deletion junctions resemble the coding joints of assembled immunoglobulin genes, tald rearrangements are likely to be mediated by aberrant activity of the immunoglobulin recombinase. Moreover, t(1;14)(p32;q11) translocations and tald rearrangements disrupt the coding potential of tal-1 in an equivalent manner, and thereby generate a common genetic lesion shared by a significant proportion of T-ALL patients.
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Affiliation(s)
- L Brown
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas
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1794
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Tang Y, Xie Y, Chai H, Chen Q. [A kindling model of epilepsy induced by intraperitoneal injection of coriaria lactone in rats]. Hua Xi Yi Ke Da Xue Xue Bao 1990; 21:304-6. [PMID: 2093070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fifty adult male Sprague-Dawley rats were divided into five groups. Intraperitoneal injections of various doses of coriaria lactone (CL, 0.75, 1.25, 1.75, and 2.0 mg/kg) and normal saline were given respectively per 2 days. The behavior of the rats was observed and the ECoG was recorded by telemetric method. The results of experiments show that a kindling model of epilepsy can be established by intraperitoneal injection of CL in rats. This chronic experimental model is of value for application because it is easily established and the rate of being kindled is relatively high, but the mortality is low, and the kindling effect can last well. The model can avert the pathological change caused by artificial injury to brain, so it is advantageous to the research on neurochemistry and ultrastructure. In our experimental condition, it is optimal to select 1.25 mg/kg or 1.75 mg/kg as the dosage of CL for establishing kindling model.
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1795
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Chen Q, Klemm N, Jeng IM. Indirect inactivation of rat brain cytosolic diacylglycerol kinase by nucleoside-5'-monophosphate. Biochem Int 1990; 21:959-65. [PMID: 2175187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cytosolic diacylglycerol kinase was inhibited drastically by nucleoside monophosphate. The inhibition was relatively specific for adenosine-5'-monophosphate (5'-AMP), although uridine-5'-monophosphate was also effective. The effect of 5'-AMP on diacylglycerol kinase appeared to be indirect since the degree of inhibition lessened with the dilution of the cytosol and the more purified enzyme failed to respond to 5'-AMP. A 5'-AMP-dependent mediator is proposed to be involved in the inactivation of diacylglycerol kinase.
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Affiliation(s)
- Q Chen
- Missouri Institute of Psychiatry, University of Missouri, Columbia
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1796
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Chen Q. [Management of the nursery for children with hepatitis]. Zhonghua Hu Li Za Zhi 1990; 25:391-2. [PMID: 2208413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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1797
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Abstract
Diverse higher plant species synthesize low molecular weight (LMW) heat shock proteins (HSPs) which localize to chloroplasts. These proteins are homologous to LMW HSPs found in the cytoplasm of all eukaryotes, a class of HSPs whose molecular mode of action is not understood. To obtain basic information concerning the role of chloroplast HSPs, we examined the accumulation, stability, tissue specificity, and intra-chloroplast localization of HSP21, the major LMW chloroplast HSP in pea. Intact pea plants were subjected to heat stress conditions which would be encountered in the natural environment and HSP21 mRNA and protein levels were measured in leaves and roots. HSP21 was not detected in leaves or roots before stress, but the mature, 21-kD protein accumulated in direct proportion to temperature and HSP21 mRNA levels in both tissues. All of the HSP21 in leaves was localized to chloroplasts; there was no evidence for its transport into other organelles. In chloroplast fractionation experiments, greater than 80% of HSP21 was recovered in the soluble chloroplast protein fraction. The half-life of HSP21 at control temperatures was 52 +/- 12 h, suggesting the protein's function is critical during recovery as well as during stress. We hypothesize that HSP21 functions in a catalytic fashion in both photosynthetic and nonphotosynthetic plastids.
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Affiliation(s)
- Q Chen
- Department of Biochemistry, University of Arizona, Tucson 85721
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1798
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Chen Q, Kelly JJ, Singh PP, Radhakrishna MC, Jones WP, Nann H. Effective interactions and nuclear structure using 180 MeV protons. II. 28Si(p,p'). Phys Rev C Nucl Phys 1990; 41:2514-2524. [PMID: 9966631 DOI: 10.1103/physrevc.41.2514] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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1799
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Abstract
The 58K protein is a peripheral membrane protein enriched in the acetylcholine receptor (AChR)-rich postsynaptic membrane of Torpedo electric organ. Because of its coexistence with AChRs in the postsynaptic membrane in both electrocytes and skeletal muscle, it is thought to be involved in the formation and maintenance of AChR clusters. Using an mAb against the 58K protein of Torpedo electric organ, we have identified a single protein band in SDS-PAGE analysis of Xenopus myotomal muscle with an apparent molecular mass of 48 kD. With this antibody, the distribution of this protein was examined in the myotomal muscle fibers with immunofluorescence techniques. We found that the 48K protein is concentrated at the myotendinous junctions (MTJs) of these muscle fibers. The MTJ is also enriched in talin and vinculin. By double labeling muscle fibers with antibodies against talin and the 48K protein, these two proteins were found to colocalize at the membrane invaginations of the MTJ. In cultured myotomal muscle cells, the 48K protein and talin are also colocalized at sites of membrane-myofibril interaction. The 48K protein is, however, not found at focal adhesion sites in nonmuscle cells, which are enriched in talin. These data suggest that the 48K protein is specifically involved in the interaction of myofibrillar actin filaments with the plasma membrane at the MTJ. In addition to the MTJ localization, 48K protein is also present at AChR clusters both in vivo and in vitro. Thus, this protein is shared by both the MTJ and the neuromuscular junction.
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Affiliation(s)
- Q Chen
- Department of Cell Biology Anatomy, University of North Carolina, Chapel Hill 27599
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1800
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Skulski W, Jastrzebski J, Singh PP, Chen Q, Fatyga M. Limitation of the linear momentum transfer in 4He+59Co collisions. Phys Rev C Nucl Phys 1990; 41:2605-2614. [PMID: 9966640 DOI: 10.1103/physrevc.41.2605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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