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Liang L, Kover K, Dey SK, Andrews GK. Regulation of interleukin-6 and interleukin-1 beta gene expression in the mouse deciduum. J Reprod Immunol 1996; 30:29-52. [PMID: 8920166 DOI: 10.1016/0165-0378(95)00953-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Expression and regulation of interleukin-6 (IL-6) and IL-1 beta were examined in the mouse deciduum and in experimentally induced deciduoma from 6 to 8 days postcoitum (1 dpc = vaginal plug), as well as in cultured mouse decidual cell preparations. Levels of these mRNAs in the deciduum and deciduoma were below the limits of detection by Northern blotting. However, enzymatic dispersion and culture of decidual cells and/or exposure to bacterial endotoxin-lipopolysaccharide (LPS) induced these mRNAs. IL-6 levels that accumulated in the culture medium (3990 pg/3 x 10(6) cells/day) were about 90-times higher than those of IL-1 beta (45 pg/3 x 10(6) cells/day). Progesterone (10(-7) M) modestly (40%) reduced the levels of IL-6 mRNA and protein during culture, whereas LPS dramatically (8-fold) and rapidly induced IL-6 and IL-1 beta mRNAs and proteins. In vivo, few IL-1 beta immunopositive cells were localized by immunohistochemistry in the 8 dpc deciduum. In contrast, IL-6 mRNA was localized by in situ hybridization in dispersed clusters of a few cells in the mesometrial deciduum near the center of the implantation site. LPS rapidly induced interleukin mRNAs in the deciduum and deciduoma. After LPS injection, IL-1 beta immunopositive cells were dispersed in the myometrium and mesometrial deciduum. In contrast, after LPS injection (2 h), IL-6 mRNA was abundant in 'cords' of cells that traverse the mesometrial deciduum longitudinally, as well as in cells dispersed throughout the myometrium. Thus, the IL-1 beta and IL-6 genes are expressed and regulated in distinct subsets of cells in the decidual bed. The pattern of F4/80 immunostaining is consistent with macrophages as the major, if not only, source of decidual IL-1 beta. IL-6 is also expressed in these cells. However, IL-6 gene expression is regulated in a distinct subset of cells located in the mesometrial decidual bed of the mouse.
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377
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Lee DK, Fu K, Liang L, Dalton T, Palmiter RD, Andrews GK. Transgenic mouse blastocysts that overexpress metallothionein-I resist cadmium toxicity in vitro. Mol Reprod Dev 1996; 43:158-66. [PMID: 8824913 DOI: 10.1002/(sici)1098-2795(199602)43:2<158::aid-mrd4>3.0.co;2-q] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The role of metallothionein with regard to cadmium toxicity in vitro was investigated using preimplantation mouse blastocysts derived from a transgenic strain that constitutively overexpresses metallothionein-I transgenes (MT-I*). Northern blot and in situ hybridization revealed high levels of MT-I mRNA in transgenic blastocysts when compared with control blastocysts, and reverse transcriptase-polymerase chain reaction-amplified MT-I mRNA was almost exclusively MT-I*. Moreover, pulse-labeling experiments showed that the relative rate of synthesis of MT was 9-fold higher in transgenic blastocysts. Cadmium (Cd2+) toxicity was assessed after incubating blastocysts for 4 hr in Whitten's medium containing 50 microM Cd2+. Embryos that displayed abnormal morphology were judged "sensitive". Transgenic blastocysts were more resistant to cadmium-induced morphological changes than were control blastocysts. "Sensitive" and "resistant" blastocysts were individually genotyped by polymerase chain reaction, or they were transferred to foster mothers, and embryonic development to midterm was monitored. Of the blastocysts derived from mating heterozygous transgenic males with control females, 56% were transgenic before incubation with Cd2+, whereas 95% of the blastocysts that retained normal morphology after incubation were transgenic. Moreover, after Cd2+ exposure, transgenic blastocysts with normal morphology were nine times more likely to develop to midterm than were control blastocysts with normal morphology. Blastocysts with abnormal morphology failed to develop to midterm. These studies indicate that MT plays a central role in protection from Cd2+ toxicity within the physiological context of the developing mouse embryo.
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378
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Varghese S, Delany AM, Liang L, Gabbitas B, Jeffrey JJ, Canalis E. Transcriptional and posttranscriptional regulation of interstitial collagenase by platelet-derived growth factor BB in bone cell cultures. Endocrinology 1996; 137:431-7. [PMID: 8593786 DOI: 10.1210/endo.137.2.8593786] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Platelet-derived growth factor (PDGF), a bone cell mitogen, stimulates bone collagen degradation and does not enhance bone matrix apposition rates. The mechanism of the effect on collagen degradation is unknown, and it could involve changes in interstitial collagenase synthesis. We tested the effects of PDGF on interstitial collagenase expression in cultures of osteoblast-enriched cells from fetal rat calvariae (Ob cells). After 4-8 h of treatment, PDGF BB at 0.3 nM increased steady state collagenase messenger RNA (mRNA), whereas PDGF AA had no effect. The effect of PDGF BB on collagenase transcripts was dose dependent. PDGF BB increased the levels of immunoreactive collagenase after 6 h, whereas the levels were decreased after 16 h. Stimulation of collagenase mRNA by PDGF BB was dependent on de novo protein synthesis and activation of protein kinase C. PDGF BB prolonged the half-life of collagenase mRNA in transcriptionally arrested cells. PDGF BB initially increased and subsequently decreased the rate of collagenase gene transcription and the levels of collagenase heterogeneous nuclear RNA. In conclusion, PDGF BB regulates interstitial collagenase in Ob cells by transcriptional and posttranscriptional mechanisms, and this effect may contribute to its stimulatory actions on bone collagen degradation.
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379
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Shi W, Gu M, Liang L. [The evaluation of adenosine triphosphate bioluminescence assay for chemosensitivity testing of ovarian cancer cell line]. ZHONGHUA FU CHAN KE ZA ZHI 1996; 31:79-82. [PMID: 8758798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To assess the efficacy of adenosine triphosphate (ATP) assay for chemosensitity testing of ovarian cancer cell line and to compare its predicting value with that of diphenyltetrazolium bromide (MTT) test. METHODS By using ATP assay and MTT test the cytotoxic effect of 7 anticancer drugs on ovarian cancer cell line AO were determined. The sensitivity and stability of ATP assay were compared with those of MTT test. The optimal time of exposure of the cells to the drugs before doing ATP chemosensitity assay is investigated. RESULTS (1) The results obtained by ATP assay correlate well with that by MTT test (r = 0.918 1). However, in 90% of the assay samples the cytotoxic effect of the chemotherapeutic agents on cancer cells detected by ATP assay was 10% or more stronger as compared with that determined by MTT test. The difference in sensitivity of the two assays was also demonstrated by the least number of living cells. A change of living cells of 60 per well could be detected by ATP assay while that detected by MTT test should be 200 per well. (2) By repeating the tests of a same batch of samples for 5 times, it revealed that the results obtained by ATP assay was more stable than MTT test. The difference between the sx- (standard error) of the two tests was significant (P < 0.05). (3) The optimal time of exposure of the cancer cells to the anticancer drugs for testing its chemosensitivity was 5 days. CONCLUSIONS The method of ATP assay for chemosensitivity test is simple and convenient with high sensitivity and stability. It may be used as a new in vitro chemosensitivity test in patients with ovarian cancer.
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380
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Liang L, Fu K, Lee DK, Sobieski RJ, Dalton T, Andrews GK. Activation of the complete mouse metallothionein gene locus in the maternal deciduum. Mol Reprod Dev 1996; 43:25-37. [PMID: 8720110 DOI: 10.1002/(sici)1098-2795(199601)43:1<25::aid-mrd4>3.0.co;2-w] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The mouse metallothionein (MT) gene family consists of four known members (MT-I through IV) clustered on chromosome 8. Studies reported herein examine the expression and regulation of the MT-III and MT-IV genes in specific cell types in the maternal reproductive tract, developing embryo, and fetus known to express the MT-I and -II genes. MT-III and MT-IV mRNAs were absent from the visceral yolk sac, placenta, and fetal liver, tissues with high levels of MT-I and MT-II mRNAs. In contrast, MT-III and MT-IV mRNAs were both abundant in the maternal deciduum, and in experimentally induced deciduoma on 7 and 8 days postcoitum (1 dpc = vaginal plug), as are MT-I and -II mRNAs. The abundance of each of these MT mRNAs increased coordinately during development of the deciduum (6-8 dpc), and in situ hybridization localized MT-I, MT-III, and MT-IV mRNAs to the secondary decidual zone of the antimesometrial region on 8 dpc, where in some regions all of the cells were apparently positive. Thus, all of the known mouse MT genes are co-expressed in at least some of the cells in the secondary decidual zone. Electrophoretic analysis of decidual MT suggested that the MT-I, -II, and -III isoforms are abundant proteins in the secondary deciduum. Bacterial endotoxin-lipopolysaccharide (LPS) and Zn are powerful inducers of MT-I and MT-II gene expression in many adult organs, whereas these agents apparently have little effect on MT-III and MT-IV gene expression. Neither of these agents significantly effected levels of decidual MT-III or MT-IV mRNAs in vivo or in primary cultures of decidual cells in vitro, and only modest effects of Zn on MT-I mRNA levels were noted. During 2 days of in vitro culture, decidual cell MT-I and MT-III mRNA levels remained elevated while MT-IV mRNA levels decreased. Thus, expression of the mouse MT gene locus in the deciduum appears to be developmentally regulated, and in this tissue, the MT genes are refractory to induction by Zn or inflammation.
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381
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Liang L, Ruckenstein E. Polyvinyl alcohol-polyacrylamide interpenetrating polymer network membranes and their pervaporation characteristics for ethanol-water mixtures. J Memb Sci 1995. [DOI: 10.1016/0376-7388(95)00137-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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382
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Ruckenstein E, Liang L. Polyacrylamide-reactive styrene/unsaturated polyester microgel composites. J Appl Polym Sci 1995. [DOI: 10.1002/app.1995.070570510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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383
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384
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Donkor IO, Klein CL, Liang L, Zhu N, Bradley E, Clark AM. Synthesis and antimicrobial activity of 6,7-annulated pyrido[2,3-d]pyrimidines. J Pharm Sci 1995; 84:661-4. [PMID: 7658362 DOI: 10.1002/jps.2600840526] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Four new 6H-indeno[2',1':5,6]pyrido[2,3-d]pryimidines (10-13) were synthesized via cyclocondensation reactions involving chlorovinyl aldehyde 1 or ketoaldehyde 3 and appropriately substituted 6-aminopyrimidines. The regiochemistry of the compounds was established by 1H NMR and 13C NMR spectral data as well as X-ray crystal data. Compounds 10 and 11 and previously reported homologues 14 and 15 were screened for antimicrobial activity. Moderate antimicrobial activity was observed for some of these compounds. Compound 14 was especially active against Staphylococcus aureus. Crystal data for 13 (C14H7N3Cl2) follows: monoclinic space group, P21/n; Unit cell dimensions, a = 7.284(1) A, b = 12.800(1) A, c = 13.108(1) A, beta = 93.98(1) degree, V = 1219.2(2) A3, Z = 4.
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385
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Kover K, Liang L, Andrews GK, Dey SK. Differential expression and regulation of cytokine genes in the mouse uterus. Endocrinology 1995; 136:1666-73. [PMID: 7895677 DOI: 10.1210/endo.136.4.7895677] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The present investigation examined the differential expression of cytokine genes in vivo and in vitro in the mouse uterus and their regulation by ovarian steroid hormones. The expression of interleukin-1 beta (IL-1 beta), IL-1 alpha, IL-6, and tumor necrosis factor-alpha (TNF alpha) genes was examined in the mouse uterus as well as in freshly isolated or cultured epithelial cells by Northern blot and in situ hybridization. In the day 1 pregnant (D1 = vaginal plug) uterus, the levels of IL-1 alpha and IL-1 beta messenger RNAs (mRNAs) were abundant, whereas those of TNF alpha and IL-6 were at the limits of detection. Freshly isolated D1 uterine epithelial cell preparations contained higher levels of IL-1 alpha and IL-1 beta mRNAs than those observed in the D1 whole uterus, whereas TNF alpha and IL-6 mRNA levels were consistently low. In contrast, D1 epithelial cells showed decreased levels of IL-1 beta mRNA after 1 day of culture, whereas the levels of IL-1 alpha and IL-6 mRNAs increased under similar conditions. The levels of IL-1, IL-6, and TNF alpha mRNAs were at the limits of detection in the D4 whole uterus or freshly isolated diestrous epithelial cells. However, IL-1 alpha and IL-6 mRNA levels in diestrous epithelial cells, like those in D1 epithelial cells, increased in culture. In contrast, IL-1 beta and TNF alpha mRNA levels remained low in cultured epithelial cells. In situ hybridization was used to examine the cell type-specific expression of IL-1 alpha or IL-6 mRNA in uterine sections and cultured cells. Although hybridization signals for IL-1 alpha mRNA were detected in uterine epithelial cells on D1 of pregnancy, IL-6 mRNA could not be detected. IL-1 alpha and IL-6 mRNAs could not be detected in freshly isolated diestrous epithelial cells, although a majority of the epithelial cells showed hybridization signals for these mRNAs after 2 or 4 days of culture. The effects of steroid hormones on uterine cytokine gene expression were examined by Northern blot and in situ hybridization. In adult ovariectomized mice, an injection of 17 beta-estradiol (E2), progesterone (P4), or a combination of E2 and P4 had little or no apparent effect on these cytokine mRNA levels. The results establish that uterine epithelial cells on D1 of pregnancy exhibit heightened expression of IL-1 alpha in culture. In contrast, these cells express little or no IL-6 mRNA in vivo, but show heightened expression in culture. These results suggest that an apparent loss of repression of these uterine genes occurs in culture. Furthermore, E2 and/or P4 treatments appear to have little or no effect on uterine cytokine mRNA levels in adult ovariectomized mice.
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386
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Donkor IO, Klein CL, Liang L, Hill GC. Pentamidine congeners. 3. Crystal structure and molecular modeling studies of trans-1,4-bis(4-amidinophenoxy)-2-butene. J Pharm Sci 1995; 84:448-55. [PMID: 7629735 DOI: 10.1002/jps.2600840412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
X-ray diffraction was used to confirm the geometry of trans-1,4-bis(4-amidinophenoxy)-2-butene dihydrochloride dihydrate (trans-butenamidine). trans-Butenamidine is a semirigid analogue of pentamidine that has demonstrated good anti-Pneumocystis carinii activity in rats. Molecular modeling studies revealed that unlike pentamidine or propamidine, trans-butenamidine does not discriminate between AT and TA sequences in its binding to the minor groove of DNA. Crystal data: [C18H22N4O2(2+)][Cl(-)]2[H2O]2, triclinic space group, P1, a = 9.443(1) A, b = 11.400(1) A, c = 11.919(1) A, alpha = 62.19(1) degree, beta = 81.10(1) degree, gamma = 72.19(1) degree, V = 1080.3(3) A3, Z = 2, R = 0.054 for 1149 observed reflections with I > 3 sigma (1).
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387
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Liang L, Huang CK. Tyrosine phosphorylation induced by cross-linking of Fc gamma-receptor type II in human neutrophils. Biochem J 1995; 306 ( Pt 2):489-95. [PMID: 7534066 PMCID: PMC1136544 DOI: 10.1042/bj3060489] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Neutrophils express several receptors for the Fc region of IgG molecules. Specific cross-linking of the type II receptor (Fc gamma RII) can be achieved by treating neutrophils with the Fab fragment of a specific monoclonal antibody IV.3 against the receptor followed by goat anti-mouse IgG F(ab')2 fragment. Such treatment initiates a number of neutrophil responses including the release of O2-. and increased protein tyrosine phosphorylation. The increase in tyrosine phosphorylation is rapid and transient and correlates with O2-. release. Both responses are inhibited by pretreatment of neutrophils with a protein tyrosine kinase inhibitor, genistein. The increase in protein tyrosine phosphorylation is not inhibited by pretreatment of neutrophils with pertussis toxin or an intracellular Ca2+ chelator, but is enhanced by a phosphoprotein phosphatase inhibitor, okadaic acid. The activity of a neutrophil Ca2+/calmodulin-dependent protein kinase II (CAMPKII) is also stimulated by cross-linking Fc gamma RII. The increase in CAMPKII activity is inhibited by pretreatment with either genistein or Ca2+ chelator. The results suggest that the increase in protein tyrosine phosphorylation induced by cross-linking of Fc gamma RII requires neither pertussis-toxin-sensitive G-proteins nor a rise in intracellular Ca2+ but can be regulated by protein phosphatases. Furthermore, protein tyrosine phosphorylation may be an early signal functionally linked to Fc gamma RII-mediated signal transduction leading to CAMPKII activation and O2-. release in human neutrophils.
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388
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Liang L, Huang CK. Activation of multiple protein kinases induced by cross-linking of Fc gamma RII in human neutrophils. J Leukoc Biol 1995; 57:326-31. [PMID: 7531749 DOI: 10.1002/jlb.57.2.326] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Several neutrophil protein kinases that undergo changes in activity during Fc gamma RII activation have been investigated. These kinases include calcium/calmodulin-dependent protein kinase II (CAMPKII), mitogen-activated protein kinase (MAPK), and histone H4 protein kinase (PKH4). They are rapidly and transiently activated in a dose-dependent manner by the cross-linking of Fc gamma RII. The activation of CAMPKII but neither PKH4 nor MAPK was inhibited by treating the cells with either a tyrosine kinase inhibitor, genistein, or an intracellular calcium chelator, BAPTA/AM. The superoxide production induced by cross-linking Fc gamma RII can be inhibited partially by various protein kinase inhibitors: 33% by protein kinase C inhibitor calphostin C, 30% by CAMPKII inhibitor KN-62, and 62% by tyrosine kinase inhibitor genistein. These results indicate that cross-linking of Fc gamma RII induces multiple signaling pathways that lead to the activation of various protein kinases. The activation of these kinases may be involved directly or indirectly in the regulation of superoxide production.
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389
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Horvat M, Mandi? V, Liang L, Bloom NS, Padberg S, Lee YH, Hintelmann H, Benoit J. Working Methods Paper: Certification of methylmercury compounds concentration in marine sediment reference material, IAEA-356. Appl Organomet Chem 1994. [DOI: 10.1002/aoc.590080606] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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390
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Klein CL, Lear J, O'Rourke S, Williams S, Liang L. Crystal and molecular structures of tricyclic neuroleptics. J Pharm Sci 1994; 83:1253-6. [PMID: 7830241 DOI: 10.1002/jps.2600830914] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The X-ray crystal structures of three tricyclic neuroleptics have been completed and are reported herein. These include amitriptyline hydrochloride (I), chlorprothixene hydrochloride (II), and ethopropazine hydrochloride (III). The structures were compared with the structures of similar molecules with similar pharmacological activity. It was found that there is a great deal of flexibility in the structures of these molecules, which makes it difficult to determine the pharmacologically active conformations. Crystallographic data: (I) C20H24NCl, monoclinic space group P2(1)/a, a = 13.812(4) A, b = 9.140(2) A, c = 14.345(4) A, beta = 96.82(2) degrees, Z = 4, final R = 0.059 for 1630 observed (l > 3 sigma(l)) reflections. (II) C18H20NSCl2.CHCl3, monoclinic space group C2/c, a = 29.416(4) A, b = 6.986(1) A, c = 23.374(3) A, beta = 109.78(1) degrees, Z = 8, final R = 0.046 for 1436 observed reflections. (III) C19H25N2SCl, monoclinic space group P2(1)/c, a = 8.849(1) A, b = 14.475(2) A, c = 14.832(1) A, beta = 98.72(1) degrees, Z = 4, final R = 0.039 for 2583 observed reflections.
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391
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Liang L, Diehl-Jones W, Lasko P. Localization of vasa protein to the Drosophila pole plasm is independent of its RNA-binding and helicase activities. Development 1994; 120:1201-11. [PMID: 8026330 DOI: 10.1242/dev.120.5.1201] [Citation(s) in RCA: 249] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Drosophila gene vasa encodes a DEAD-box protein, which is localized during early oogenesis to the perinuclear region of the nurse cells and later to the pole plasm at the posterior end of the oocyte. Posterior localization of vasa protein depends upon the functions of four genes: capu, spir, osk and stau. We have found that localization of vasa to the perinuclear nuage is abolished in most vas alleles, but is unaffected by mutations in four genes required upstream for its pole plasm localization. Thus localization of vasa to the nuage particles is independent of the pole plasm assembly pathway. Furthermore, electron-dense nuage particles are less abundant in the cytoplasm of nurse cells from vas mutants that fail to exhibit perinuclear localization, suggesting that the formation of the nuage depends upon vas function. Eight of nine vas point mutations cause codon substitutions in a region conserved among DEAD-box genes. The proteins from two mutant alleles that retain the capacity to localize to the posterior pole of the oocyte, vasO14 and vasO11, are both severely reduced in RNA-binding and -unwinding activity as compared to the wild-type protein on a variety of RNA substrates including in vitro synthesized pole plasm RNAs. Initial recruitment of vasa to the pole plasm must consequently depend upon protein-protein interactions but, once localized, vasa must bind to RNA to mediate germ cell formation.
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392
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Liang L, Bloom NS, Horvat M. Simultaneous determination of mercury speciation in biological materials by GC/CVAFS after ethylation and room-temperature precollection. Clin Chem 1994; 40:602-7. [PMID: 8149617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We developed a method for the simultaneous determination of monomethyl mercury (MMHg), inorganic mercury [Hg(II)], and total mercury (THg) in biological materials. A variety of biological materials can be digested in methanolic KOH solution. The MMHg and Hg(II) present are converted to volatile ethyl derivatives, methylethyl mercury and diethyl mercury, by an aqueous-phase ethylation reaction with sodium tetraethylborate. The ethyl derivatives are precollected onto a trapping column at room temperature, in case of disconnection with the separation/detection system, and then thermally desorbed into a packed isothermal gas chromatography (GC) column. Eluted organo-Hg compounds from the GC column are decomposed into Hg0, and detection is completed by cold vapor atomic fluorescence spectrometry (CVAFS). Pure standard solutions can be used for calibration. The sum of MMHg and Hg(II) obtained by this method equals the THg value obtained by digestion with HNO3 and H2SO4, reduction with SnCl2, and single-stage amalgamation/CVAFS for all biological materials studied. Absolute detection limits are 0.6 pg and 1.3 pg of Hg as MMHg and Hg(II), respectively, corresponding to 0.3 ng and 0.6 ng/g (wet) of sample.
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393
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Huang CK, Coleman H, Stevens T, Liang L. Rapid modification of ribosomal S6 kinase II (S6KII) in rabbit peritoneal neutrophils stimulated with chemotactic factor fMet-Leu-Phe. J Leukoc Biol 1994; 55:430-6. [PMID: 8145012 DOI: 10.1002/jlb.55.4.430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The ribosomal S6 kinase II (S6KII) in rabbit neutrophils was studied by immunoblotting with antibodies prepared against recombinant S6KII. A protein with apparent molecular weight of 80,000 Da in SDS-gel was recognized by the antibodies. A shift of the apparent molecular weight to 84,000 Da in SDS-gel was observed in cells stimulated with the chemotactic factor fMet-Leu-Phe. Cytochalasin B and phorbol 12-myristate 13-acetate, but not A23187, stimulated both the tyrosine phosphorylation of p41mapk and the change of the mobility of S6KII. Pretreatment of the cells with quin 2/AM inhibited almost completely the tyrosine phosphorylation of p41mapk induced by fMet-Leu-Phe, but only partially the change in mobility of S6KII. Under various conditions, near maximum conversion of S6KII was observed even if only about 40% of the maximum level of tyrosine phosphorylation of p41mapk was achieved. The results suggest that rapid modification of S6KII occurs in chemotactic factor-stimulated neutrophils. Furthermore, the modification of S6KII induced by fMet-Leu-Phe requires either only partial tyrosine phosphorylation of p41mapk or the activation of kinase(s) other than the p41mapk isoform.
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394
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Liang L, Bloom NS, Horvat M. Simultaneous determination of mercury speciation in biological materials by GC/CVAFS after ethylation and room-temperature precollection. Clin Chem 1994. [DOI: 10.1093/clinchem/40.4.602] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
We developed a method for the simultaneous determination of monomethyl mercury (MMHg), inorganic mercury [Hg(II)], and total mercury (THg) in biological materials. A variety of biological materials can be digested in methanolic KOH solution. The MMHg and Hg(II) present are converted to volatile ethyl derivatives, methylethyl mercury and diethyl mercury, by an aqueous-phase ethylation reaction with sodium tetraethylborate. The ethyl derivatives are precollected onto a trapping column at room temperature, in case of disconnection with the separation/detection system, and then thermally desorbed into a packed isothermal gas chromatography (GC) column. Eluted organo-Hg compounds from the GC column are decomposed into Hg0, and detection is completed by cold vapor atomic fluorescence spectrometry (CVAFS). Pure standard solutions can be used for calibration. The sum of MMHg and Hg(II) obtained by this method equals the THg value obtained by digestion with HNO3 and H2SO4, reduction with SnCl2, and single-stage amalgamation/CVAFS for all biological materials studied. Absolute detection limits are 0.6 pg and 1.3 pg of Hg as MMHg and Hg(II), respectively, corresponding to 0.3 ng and 0.6 ng/g (wet) of sample.
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395
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Liang L, Jiang Z, Liu Z, Liu W. Clinical observation on osteoporosis treated with traditional kidney-tonifying medicaments. J TRADIT CHIN MED 1994; 14:41-4. [PMID: 8196417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The method of scoring kidney deficiency symptoms and bone density was used to judge therapeutic efficacy on osteoporosis of traditional kidney-tonifying drugs. It was proved that the drugs not only improved clinical symptoms but also delayed the developmental process of this disorder. It also verified the correctness of the traditional theory that the kidney dominates the bone and generates the marrow.
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396
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Liang L, Horvat M, Bloom N. An improved speciation method for mercury by GC/CVAFS after aqueous phase ethylation and room temperature precollection. Talanta 1994; 41:371-9. [DOI: 10.1016/0039-9140(94)80141-x] [Citation(s) in RCA: 296] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/1993] [Revised: 09/10/1993] [Accepted: 09/13/1993] [Indexed: 11/30/2022]
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397
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Porter KR, Liang L, Long GW, Bangs MJ, Anthony R, Andersen EM, Hayes CG. Evidence for anti-Plasmodium falciparum antibodies that cross-react with human T-lymphotropic virus type I proteins in a population in Irian Jaya, Indonesia. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1994; 1:11-5. [PMID: 7496910 PMCID: PMC368188 DOI: 10.1128/cdli.1.1.11-15.1994] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
This study was performed to demonstrate the presence of anti-Plasmodium falciparum antibodies in a population living in Irian Jaya, Indonesia that cross-react with human T-lymphotropic virus type I (HTLV-I) proteins. Serum samples from 63 volunteers living in Oksibil, a secluded highland valley in Irian Jaya, were tested for anti-P. falciparum antibodies by an immunofluorescence assay and for anti-HTLV-I antibodies by an enzyme immunoassay (EIA). All samples were positive for anti-P. falciparum antibodies at titers of > or = 1:256. Twenty-four samples were reactive by EIA for HTLV-I, and of these, 23 were tested by western blotting (immunoblotting). Five of the 23 samples were classified as western blot positive and 18 were classified as western blot indeterminate. In competitive blocking assays with malaria proteins, western blot immunoreactivity to all HTLV-I Gag proteins was either reduced or eliminated. Significant reductions in the HTLV-I EIA optical density values of the Oksibil sera occurred when the sera were competitively blocked with the malaria antigens. The optical density values of HTLV-I-positive control sera showed no significant change. Competitive blocking with HTLV-I antigens produced reductions in the optical density values of both the Oksibil sera and the HTLV-I-positive control sera. These data suggest that in this population, anti-P. falciparum antibodies are cross-reactive with HTLV-I proteins in the western blot and EIA tests.
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398
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Erickson K, Liang L, Shum P, Nathanson JA. Adrenergic regulation of aqueous outflow. JOURNAL OF OCULAR PHARMACOLOGY 1994; 10:241-52. [PMID: 7911501 DOI: 10.1089/jop.1994.10.241] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Epinephrine increased outflow facility and cyclic AMP in the in vitro perfused human anterior segment with a maximal facility increase of 44% occurring at approximately 2 x 10(-5) M. Cyclic AMP measured in the perfusate from anterior segments increased by 12-14 fold after administration of 10(-5) M epinephrine. Both the facility increase and cyclic AMP rise were blocked by the beta-2 selective antagonist, ICI118,551. While there was a correlation between the facility increase and elevation in cyclic AMP levels, the rise in cyclic AMP preceded the facility increase by about 1 hour, suggesting that the ultimate effect of epinephrine involved a rather slow event such as synthesis and release of prostaglandins or protein synthesis. Subsequent perfusion studies showed that very large concentrations of indomethacin were necessary to block the outflow facility effect of epinephrine, suggesting that prostaglandin synthesis did not underlie the facility effect in this system. However, 5 x 10(-5) M cyclohexamide blocked the effect on outflow facility of both epinephrine and forskolin, but did not block the rise in cyclic AMP. These studies suggest that protein synthesis may play a role in the epinephrine-induced facility increase at some point beyond the second messenger level.
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399
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Gu B, Schmitt J, Chen Z, Liang L, McCarthy JF. Adsorption and desorption of natural organic matter on iron oxide: mechanisms and models. ENVIRONMENTAL SCIENCE & TECHNOLOGY 1994; 28:38-46. [PMID: 22175831 DOI: 10.1021/es00050a007] [Citation(s) in RCA: 534] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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400
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Wang HC, Lu JY, Liang L, Liu HL. Evaluation of the potential role of enzyme-linked immunosorbent assay in serodiagnosis of tuberculosis. ZHONGHUA YI XUE ZA ZHI = CHINESE MEDICAL JOURNAL; FREE CHINA ED 1993; 52:9-14. [PMID: 8364785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The serodiagnosis of tuberculosis was evaluated by means of enzyme-linked immunosorbent assay of IgG antibody to mycobacterial antigen 60. The study population consisted of 63 patients with active tuberculosis comprising 43 pulmonary tuberculosis, 15 tuberculosis pleurisy, four miliary tuberculosis, and one tuberculous lymphadenitis. The control group consisted of 48 patients embracing 8 cases of inactive pulmonary tuberculosis, 31 cases of pulmonary disorders other than tuberculosis, and nine normal persons. There was a significant difference in antibody titers of sera between patients of active tuberculosis and control group (P < 0.001). The sensitivity of the test for active pulmonary tuberculosis was 81.4% and the specificity was 85.4% (cutoff value 300 units). The sensitivity for all active tuberculosis was 61.9%. There was positive correlation between serum titer of active pulmonary tuberculosis and the extent of disease on chest radiography (r = 0.4, P < 0.01). A positive correlation was found between the titers of pleural fluids, and the corresponding sera in 15 patients (eleven tuberculous pleurisy and four nontuberculous controls) (r = 0.85, P < 0.001). Whether serum or pleural fluid, the positive rate of the assay for tuberculous pleurisy was relatively low. In conclusion, the A60 IgG ELISA test may be useful in serodiagnosis of pulmonary tuberculosis and assessment of the disease extent, although it might not yield a high sensitivity for tuberculous pleurisy.
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