701
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Gu Y, Hukriede NA, Fleming RJ. Serrate expression can functionally replace Delta activity during neuroblast segregation in the Drosophila embryo. Development 1995; 121:855-65. [PMID: 7720588 DOI: 10.1242/dev.121.3.855] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Serrate and Delta encode structurally related proteins in D. melanogaster that bind within a common extracellular region on the NOTCH receptor molecule. We used ectopic expression to determine if SERRATE could mediate in vivo functions parallel or antagonistic to those proposed for the putative NOTCH ligand DELTA. Our results demonstrate that Serrate can replace Delta gene function during embryonic neuroblast segregation and that expression of Serrate leads to a NOTCH-dependent suppression of achaete expression in proneural clusters. Our findings strongly suggest that SERRATE functions as an alternative ligand capable of NOTCH activation.
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702
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Chen D, Cai P, Lao G, Gu Y. Quadrilateral space syndrome. Chin Med J (Engl) 1995; 108:109-12. [PMID: 7774383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We studied 4 cases of quadrilateral space syndrome. Though the syndrome is quite uncommon, it might be discovered by examination of the patient complaining of pain of neck and shoulder especially when the tenderness in the quadrilateral space. Early surgical decompression is indicated as soon as diagnosis is made.
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703
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Chen L, Gu Y, Huang LY. The opioid peptide dynorphin directly blocks NMDA receptor channels in the rat. J Physiol 1995; 482 ( Pt 3):575-81. [PMID: 7537820 PMCID: PMC1157783 DOI: 10.1113/jphysiol.1995.sp020541] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
1. The actions of dynorphin on N-methyl-D-aspartate (NMDA) responses were examined in acutely dissociated trigeminal neurons in rat. Whole-cell and single-channel currents were recorded using the patch clamp technique. 2. Dynorphins reduced NMDA-activated currents (INMDA). The IC50 was 0.25 microM for dynorphin (1-32), 1.65 microM for dynorphin (1-17) and 1.8 microM for dynorphin (1-13). 3. The blocking action of dynorphin is voltage independent. 4. The inhibitory action of dynorphin cannot be blocked by high concentration of the non-selective opioid receptor antagonist naloxone, nor by the specific kappa-opioid receptor antagonist nor-Binaltorphimine (nor-BNI). 5. Single-channel analyses indicate that dynorphin reduces the fraction of time the channel is open without altering the channel conductance. 6. We propose that dynorphin acts directly on NMDA receptors.
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704
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Gu Y. Progress in hand surgery of China. Chin Med J (Engl) 1995; 108:68-72. [PMID: 7712846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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705
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Gu Y, Lee H, Hudson RA. Bis-catechol-substituted redox-reactive analogues of hexamethonium and decamethonium: stimulated affinity-dependent reactivity through iron peroxide catalysis. J Med Chem 1994; 37:4417-20. [PMID: 7996555 DOI: 10.1021/jm00051a021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Symmetrically bis-catechol-substituted analogues (1 and 2, respectively) of hexamethonium and decamethonium were synthesized and investigated as redox-activated affinity reagents toward the neurotoxin-binding sites of the nicotinic acetylcholine receptor (nAcChR), purified from Torpedo californica electroplax. These reagents bound to nAcChR with Kd = 1.8 x 10(-8) and 2.3 x 10(-7) M for 1 and 2, respectively. In the presence of a metal, Fe(II)/Fe(III), and peroxide, both reagents produced a rapid and efficient half-of-sites inactivation of neurotoxin-binding sites in the nAcChR in a concentration-dependent manner, which paralleled the extent of receptor binding of the reagents. In the absence of Fe(II)/Fe(III) peroxide, redox-dependent inactivation occurred for both 1 and 2 more slowly and only at concentrations much higher (10(3)-10(4) times) than those necessary to produce significant binding to nAcChR. However, receptor inactivation in the absence of added metal peroxide was still more efficient for 1 and 2 than observed previously for [(trimethylammonio)methyl]catechol (3), the prototypic redox-dependent affinity reagent after which 1 and 2 were patterned. Thus, the new reagents reported are expected to provide more efficient and selective conditions for redox-dependent inactivation at nAcChR and other macromolecular sites to which such reagents may be directed.
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706
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Chen H, Guo Z, Gu Y. [A study on relation between effect of HB vaccination and time of the second injection]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1994; 15:349-50. [PMID: 7874704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Three kinds of hepatitis B vaccination schedule in neonates were compared. The schedule included 0, 40 day, 6 month; 0, 50 day, 6 month; 0, 60 day, 6 month; and was controlled by the 0, 30 day, 6 month schedule. The results showed that there was no statistically significant difference among three kinds of schedule, no matter who were neonates of HBs Ag-positive mother or neonates of HBsAg-negative mother. These indicated that in areas with poor condition, such as mountain, island, the second injection of hepatitis B vaccine in neonates may be completed within 30-60 days.
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707
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Gu Y, Zhang G, Cheng D. [Clinical application of neurovascular island flap in the hand]. ZHONGHUA ZHENG XING SHAO SHANG WAI KE ZA ZHI = ZHONGHUA ZHENG XING SHAO SHANG WAIKF [I.E. WAIKE] ZAZHI = CHINESE JOURNAL OF PLASTIC SURGERY AND BURNS 1994; 10:418-422. [PMID: 7719996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
From 1962 to 1992, four kinds of neurovascular island flaps of the hand were used for the treatment of skin defects in the hand in 72 cases. Of these flaps, 38 were pulp flaps of the finger, 24 were based on the first dorsal metacarpal artery, 7 were from second dorsal metacarpal artery and 3 were from hypothenar area. All the flaps survived except 1. Postoperative follow-up showed excellent or good results in 94.4%. The indications of the operation, flap design and surgical procedure are described. The anatomical feature, the advantages and disadvantages of the flap are discussed.
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708
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Aydintug MK, Gu Y, Philipp MT. Borrelia burgdorferi antigens that are targeted by antibody-dependent, complement-mediated killing in the rhesus monkey. Infect Immun 1994; 62:4929-37. [PMID: 7927774 PMCID: PMC303209 DOI: 10.1128/iai.62.11.4929-4937.1994] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We identified surface antigens of Borrelia burgdorferi that are targeted by antibody-dependent, complement-mediated killing (ADCK) in the rhesus monkey. For this purpose, we had available serum samples from three animals infected with B. burgdorferi JD1 by needle inoculation and from two monkeys that were infected with the same B. burgdorferi strain by Ixodes scapularis tick bite. Sera from monkeys from the first group contained antibodies to OspA and OspB detectable by Western blot (immunoblot) using whole B. burgdorferi antigens, whereas serum samples from animals in the second group did not. The targeting of OspA and OspB by functional antibodies was demonstrated directly by showing that ADCK was partially inhibited when antibodies were preincubated with an excess of soluble recombinant OspA or OspB. Simultaneous addition of OspA and OspB did not result in an additive inhibitory effect on ADCK, a result that suggests that the epitopes on OspA and that on OspB targeted by antibody in this mechanism are the same, or at least cross-reacting. The targeting of non-OspA, non-OspB surface antigens was inferred from the fact that sera from tick-inoculated animals, which did not contain detectable anti-OspA or anti-OspB antibodies, were able to effect ADCK. This killing effect was not inhibitable by the addition of recombinant OspA or OspB or both proteins together. We also showed that both immunoglobulin G and M antibodies participate in the ADCK mechanism in the rhesus monkey. Rhesus complement does not kill B. burgdorferi in vitro in the absence of antibody, and antibody alone is effective in killing only at serum dilutions lower than 1:15. However, such "complement-independent" antibodies were not present in all bleeds. Two main conclusions may be drawn from the analysis of our results. First, both OspA and OspB are targeted by the ADCK mechanism in the rhesus monkey. Second, one or more B. burgdorferi surface antigens that are neither OspA nor OspB also participate in ADCK.
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709
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Abstract
It is well established that rat decidual tissue produces a PRL-like hormone(s) that binds to the PRL receptor on both the corpus luteum and the decidual cells and initiates profound changes in the endocrine milieu required for the establishment of pregnancy. The recent cloning of a decidual PRL-related protein (dPRP) prompted us 1) to determine whether the expression of this gene is triggered by decidualization of the endometrial stromal cells, 2) to examine the temporal and cell-specific pattern of its expression, and 3) to examine the role of both decidual signals and PRL on levels of its messenger RNA (mRNA). Total RNA was isolated from uteri of either nonpseudopregnant rats or pseudopregnant rats with or without decidual tissue. A 1-kilobase mRNA species hybridizing strongly with the dPRP probe was present in decidualized uteri. No dPRP mRNA could be detected in uteri not subjected to decidualization. Developmental studies indicated a constant high level of dPRP mRNA in the decidual tissue until day 12 of pseudopregnancy, followed by a marked decline at a time when extensive cell death occurs in the decidua, suggesting that dPRP is constitutively expressed in this tissue. To examine the cell-specific expression of dPRP, antimesometrial decidua was separated from mesometrial decidua, and the large antimesometrial cell population was separated from the small mesometrial cells by elutriation. The results of Northern analysis revealed clearly that dPRP is abundantly and solely expressed in the large antimesometrial cells. No dPRP mRNA could be detected in the mesometrial cells and in numerous other endocrine and nonendocrine tissues. A faint signal was observed, however, in the trophoblast. Despite the very strong paracrine regulation between the antimesometrial and mesometrial cells and the high levels of PRL receptor expression in these cells, both in vivo and coculture experiments revealed no regulation of dPRP gene expression by either PRL or mesometrial cell signal, adding further support to the possibility that once induced, dPRP remains constitutively expressed. In summary, the results of this investigation revealed that the expression of dPRP in endometrial stromal cells is triggered by the induction of decidualization and that this gene is selectively and abundantly expressed in a defined cell population located in the anti-mesometrial region of the uterus. Thus, dPRP is not only a useful indicator of decidualization, but is also an excellent marker for the differentiated antimesometrial cells.
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710
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Gu Y, Jow GM, Moulton BC, Lee C, Sensibar JA, Park-Sarge OK, Chen TJ, Gibori G. Apoptosis in decidual tissue regression and reorganization. Endocrinology 1994; 135:1272-9. [PMID: 8070373 DOI: 10.1210/endo.135.3.8070373] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
During blastocyst implantation, cellular degeneration of decidual tissue spreads from the antimesometrial region to the mesometrial region to accommodate the developing conceptus. To identify the mechanism of decidual regression and its tissue localization, decidual formation was induced in either intact pseudopregnant rats or ovariectomized rats treated with steroids. Antimesometrial and mesometrial cells were separated by elutriation and cultured for 48 h before DNA analysis. Nucleosomal DNA fragmentation was observed in antimesometrial cells, whereas DNA fragmentation was less marked in mesometrial cells. To determine whether a similar pattern of apoptosis occurred during decidual development in vivo, decidua tissues from antimesometrial and mesometrial regions were obtained on days 8-14. Nucleosomal DNA fragmentation was first detected on day 10 in the antimesometrial region, with fragmentation in the mesometrial region delayed by at least 24 h. DNA fragmentation increased in both tissues with time, but was always more pronounced in antimesometrial cells. Sulfated glycoprotein-2 (SGP-2) has been associated with apoptosis, and its expression was examined by Northern analysis. Levels of SGP-2 messenger RNA (mRNA) were detected in the antimesometrial region on day 9 and increased markedly by day 10; mesometrial expression was delayed 24 h. Levels of SGP-2 mRNA in both regions decreased before the onset of DNA fragmentation. In contrast, cathepsin-D expression, detected by immunohistochemistry, was localized to few mesometrial and antimesometrial cells between days 9-12, with all cells showing extensive staining by day 14. To determine whether changes in progesterone control mechanisms initiated decidual apoptosis, plasma progesterone levels were measured by RIA, and progesterone receptor mRNA levels in decidual tissues were examined by reverse transcription-polymerase chain reaction. Both parameters remained unchanged during decidual growth and regression. These results provide biochemical evidence that decidual regression occurs by apoptosis initiated in the antimesometrial region and with progression to the mesometrial region. Apoptotic cell death occurs despite high levels of plasma progesterone and high levels of progesterone receptor message in decidual tissue.
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711
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Gu Y, Lugenbeel KA, Vockley JG, Grody WW, Nelson DL. A de novo deletion in FMR1 in a patient with developmental delay. Hum Mol Genet 1994; 3:1705-6. [PMID: 7530551 DOI: 10.1093/hmg/3.9.1705] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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712
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Prasad R, Leshkowitz D, Gu Y, Alder H, Nakamura T, Saito H, Huebner K, Berger R, Croce CM, Canaani E. Leucine-zipper dimerization motif encoded by the AF17 gene fused to ALL-1 (MLL) in acute leukemia. Proc Natl Acad Sci U S A 1994; 91:8107-11. [PMID: 8058765 PMCID: PMC44554 DOI: 10.1073/pnas.91.17.8107] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Chromosome region 11q23 is involved in reciprocal chromosome translocations associated with human acute leukemias. These aberrations fuse the ALL-1 gene located at 11q23 to a series of partner genes positioned on a variety of human chromosomes. The fused genes encode chimeric proteins. Here we report the cloning and characterization of the ALL-1 partner at 17q21, the AF17 gene. The AF17 gene encodes a protein of 1093 amino acids, containing a leucine-zipper dimerization motif located 3' of the fusion point and a cysteine-rich domain at the N terminus. The latter can be arranged in three zinc fingers and shows homology to a domain within the protein Br140 (peregrin). AF17 contains stretches of amino acids previously associated with domains involved in transcriptional repression or activation. Based on features of AF17 and of the proteins encoded by the other partner genes analyzed and in conjunction with other recent studies, we propose a model in which ALL-1 rearrangements result in loss of function of the gene. In this model, the partner polypeptide plays an accessory role either by repressing activity of the truncated ALL-1 protein or by blocking the function of the normal protein presumably present in the leukemic cells.
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713
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Schichman SA, Caligiuri MA, Strout MP, Carter SL, Gu Y, Canaani E, Bloomfield CD, Croce CM. ALL-1 tandem duplication in acute myeloid leukemia with a normal karyotype involves homologous recombination between Alu elements. Cancer Res 1994; 54:4277-80. [PMID: 8044771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Rearrangements of the ALL-1 gene by reciprocal translocations involving chromosome band 11q23 are frequently associated with human acute leukemia. We have previously reported the detection of ALL-1 gene rearrangements in adult patients with acute myeloid leukemia lacking cytogenetic evidence of 11q23 translocations. These included 2 of 19 patients with normal karyotypes as well as 3 of 4 patients with trisomy 11 as a sole cytogenetic abnormality. Rearrangement of the ALL-1 genes in two of the patients with trisomy 11 was shown to result from a direct tandem duplication of a portion of the gene spanning exons 2-6. Here we report the characterization of the ALL-1 gene rearrangement in one of the previously reported acute myeloid leukemia patients with a normal karyotype. ALL-1 rearrangement in this patient results from a direct tandem duplication of a portion of the gene spanning exons 2-8. RNA polymerase chain reaction and DNA sequence analysis show that the partially duplicated ALL-1 gene is transcribed into mRNA capable of encoding a partially duplicated protein. Sequence analysis of the genomic fusion region provides evidence for Alu-mediated homologous recombination as a mechanism for partial duplication of the ALL-1 gene.
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714
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Gu Y, Lee H, Kirchhoff JR, Manzey L, Hudson RA. Mechanism of action of the redox affinity reagent [(trimethylammonio)methyl]catechol. Biochemistry 1994; 33:8486-94. [PMID: 8031782 DOI: 10.1021/bi00194a013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The synthesis of 4- and 5-hydroxy-3-[(trimethylammonio)methyl]catechol (4- and 5-HTMC) was carried out to examine their proposed involvement as intermediates in the spontaneous redox-dependent half-of-sites inactivation of neurotoxin binding sites in the nicotinic acetylcholine receptor (nAcChR) mediated by the parent compound 3-[(trimethylammonio)methyl]catechol (TMC) [Nickoloff et al. (1985) Biochemistry 24, 999-1007]. Oxidation of 4- and 5-HTMC occurred with sodium periodate with facile conversion to the corresponding p-quinones which were intercepted with thiols and cyclopentadiene. Both 4- and 5-HTMC inactivated neurotoxin binding in the nAcChR in a time course and over a concentration range consistent with their involvement as intermediates in the TMC redox-dependent inactivation of neurotoxin ([125I]-alpha-bungarotoxin) binding sites. Rapid concentration-dependent inactivation of neurotoxin sites occurred over a 10-1000 microM range and was resistant to further inactivation after 50% loss of available toxin binding sites on the nAcChR. Both 4- and 5-HTMC inactivated nAcChR neurotoxin sites much more rapidly and efficiently than was observed previously with TMC. The apparent binding constants for 4- and 5-HTMC with the nAcChR, calculated from their concentration-dependent inactivation behavior toward toxin binding sites, were Kd = 224 +/- 98 and 39 +/- 17 microM, respectively. The observed results and the redox potentials (vs Ag/AgCl reference electrode) measured by cyclic voltammetry at pH 1.8 for TMC (719 mV) and the 4- and 5-HTMC derivatives (519 and 443 mV, respectively) supported the previously proposed mechanism for inactivation of the nAcChR by TMC.(ABSTRACT TRUNCATED AT 250 WORDS)
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715
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Gu Y, Huang LY. Modulation of glycine affinity for NMDA receptors by extracellular Ca2+ in trigeminal neurons. J Neurosci 1994; 14:4561-70. [PMID: 8027794 PMCID: PMC6577052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Glycine and the divalent cation Ca2+ play key roles in regulating the activity of excitatory amino acid NMDA receptor channels. There is accumulating evidence that the concentration of glycine at the synaptic cleft is below a saturated level. We examined the effect of external Ca2+ on NMDA responses in various concentrations of glycine in isolated trigeminal neurons. We found that external Ca2+ potentiated NMDA responses and this potentiation occurred only when glycine sites were unsaturated. Since single-channel conductance decreases in the high external Ca2+ solution, the observation cannot be explained by an increase in Ca2+ influx through the channels. Studying the dose-response curves for glycine in different Ca2+ solutions, we found that the apparent dissociation constant (EC50) for glycine decreases with increasing external Ca2+ concentrations. Kinetics studies of glycine binding to NMDA receptors indicated that external Ca2+ causes a decrease in the off rate of the glycine binding, while having no effect on the on rate. Our analyses suggest that the apparent glycine affinity increases by about 3.7 times in Ca-containing solution. Thus, external Ca2+ contributes to the unusually high glycine affinity for NMDA receptors and may have a role in regulating the NMDA receptor channel activities during intensive or sustained neuronal stimulation.
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716
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Hosotani R, Doi R, Gu Y, Wada M, Inoue K, Fujii N, Rayford PL, Imamura M. Metabolism of cholecystokinin-33 in vivo: effect of L-364,718, a CCK receptor antagonist. ANNALS OF CLINICAL AND LABORATORY SCIENCE 1994; 24:346-54. [PMID: 7944271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Metabolism of cholecystokinin (CCK) and the effect of L-364,718, a specific CCK-A receptor antagonist, on the metabolism of CCK were examined in dogs. In conscious dogs, 45 min intravenous infusion of synthetic human CCK-33 (100 pmol/Kg/hr) caused an integrated CCK response over 90 min of 675 +/- 51 pmol-90 min/L, and the plasma CCK levels declined promptly with a t1/2 of 2.2 +/- 0.3 min after cessation. Organ extraction of CCK-33 by the kidney, mesenteric organs, and liver was examined in anesthetized dogs. From the gradients of the plasma levels between afferent and efferent vessels for each organ after bolus injection of CCK-33 (50 pmol/Kg), renal extraction ratio was 0.30 +/- 0.04, and mesenteric extraction ratio was 0.19 +/- 0.04. Hepatic extraction was not detected. T1/2 and extraction ratios were not affected by the preinjection of L-364,718 (20 nmol/Kg). The results indicate in dogs that exogenously administered CCK-33 is degraded by the mesenteric organs as well as the kidney but not by the liver, and that receptor-mediated mechanisms are not involved in these degradation pathways of CCK.
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717
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Schichman SA, Caligiuri MA, Gu Y, Strout MP, Canaani E, Bloomfield CD, Croce CM. ALL-1 partial duplication in acute leukemia. Proc Natl Acad Sci U S A 1994; 91:6236-9. [PMID: 8016145 PMCID: PMC44173 DOI: 10.1073/pnas.91.13.6236] [Citation(s) in RCA: 162] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The ALL-1 gene, located on chromosome band 11q23, is fused to a variety of other genes by reciprocal chromosomal translocations present in 5-10% of human acute leukemias. We have recently reported the detection by Southern blot of ALL-1 gene rearrangements in adult patients with acute myeloid leukemia lacking cytogenetic evidence of 11q23 translocations. These include 2 of 19 patients with normal karyotypes as well as 3 of 4 patients with trisomy 11. To characterize the abnormal ALL-1 genes, we cloned the ALL-1 rearrangements from two patients with trisomy 11. Characterization of the clones, together with Southern blot analysis, indicates that the ALL-1 rearrangement in both patients is the result of a direct tandem duplication of a portion of the ALL-1 gene spanning exons 2-6. The partial ALL-1 duplication is also detected by Southern blot analysis in a patient with a normal karyotype. RNA PCR and DNA sequence analysis show that the partially duplicated ALL-1 gene is transcribed into mRNA capable of encoding a partially duplicated protein. Partial duplication of ALL-1, in which a portion of a putative protooncogene is fused with itself, represents an additional genetic mechanism for leukemogenesis. Our findings suggest that the presence of trisomy in malignancy may sometimes indicate the partial duplication of a cellular protooncogene.
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718
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Gu Y, Alder H, Nakamura T, Schichman SA, Prasad R, Canaani O, Saito H, Croce CM, Canaani E. Sequence analysis of the breakpoint cluster region in the ALL-1 gene involved in acute leukemia. Cancer Res 1994; 54:2327-30. [PMID: 8162575] [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
DNA rearrangements caused by chromosome translocations between band 11q23 and various chromosomes can be detected by a single probe, B859, an 859-base pair complementary DNA fragment derived from the human ALL-1 gene. To try to understand why band 11q23 becomes a frequent target of the translocations, we have sequenced the entire breakpoint cluster region, a 8342-base pair BamHI genomic fragment delineated by B859. We found eight Alu repeats located within this region in the same orientation as the ALL-1 gene. We have also analyzed the sequences of the breakpoints in 10 patients with 6 different types of 11q23 aberration. In five patients the breaks coincided with Alu sequences on chromosome 11, but not on the partner chromosomes. Also, seven of the breaks occurred in the region delineated by exons 6 and 7, which is composed mainly of Alu sequences. In three patients topoisomerase II recognition site-like sequences, at different stringency levels, were identified at the breakpoints on chromosome 11. We conclude that while there is no specific sequence element present at all the breakpoints, the high density of Alu sequences in the breakpoint cluster region possibly makes the latter more prone to recombination events.
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719
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Gu Y, Crawford JW, Ramanee Peiris D, Jefferies RA. An approach for treating the uncertainties in the impact of climate change. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 1994; 83:87-93. [PMID: 15091754 DOI: 10.1016/0269-7491(94)90026-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Past accumulated data supported by the predictions of climate models suggest that our world is getting warmer. Scientists are trying to construct mathematical models of both climate and crop systems to identify what types of climate changes could constitute a significant risk or benefit for agriculture. However, due to the many uncertainties regarding these models, it is impossible to make unequivocal predictions. At present, almost all the research in this area is carried out without considering the uncertain nature of the problem. The approach outlined here attempts to find a way to deal with the above uncertainty problem. Artificial intelligence techniques are being developed with the aim of performing inferences based on uncertain information. In our method, causal graphs are used for explicit representation of the relationships between climatic factors and yield. Probabilities are used to express the uncertainties associated with these links, and Bayes' theorem is applied to deal with uncertainty reasonings. This approach has the additional advantage of allowing the prediction to be readily updated as results from improved climate and crop models become available. These opportunities are being evaluated initially by using the model for potato growth developed at the Scottish Crop Research Institute.
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720
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Gu Y, Turck CW, Morgan DO. Inhibition of CDK2 activity in vivo by an associated 20K regulatory subunit. Nature 1993; 366:707-10. [PMID: 8259216 DOI: 10.1038/366707a0] [Citation(s) in RCA: 587] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The major events of the cell division cycle are triggered by periodic changes in the activity of cyclin-dependent protein kinases (CDKs). In mammals, the members of the CDK family include CDK2 and CDC2, which are thought to be involved in the control of DNA replication and mitosis, respectively. The protein kinase activity of these enzymes is controlled by a complex array of mechanisms. Activation of the CDK catalytic subunit requires association with a positive regulatory subunit (cyclin) and phosphorylation (at Thr 160 in CDK2). This activated complex can be inhibited by additional phosphorylation at Thr 14 and Tyr 15. Here we report the identification of a new mechanism for the regulation of CDK2 activity. We find that CDK2/cyclin complexes in mouse fibroblasts associate tightly with a 20K protein (CAP20). Complexes containing CAP20 were isolated from cell lysates and found to have negligible kinase activity, indicating that CAP20 association in vivo may inhibit CDK2 activity. We purified CAP20 from 3T3 cells and found that low concentrations of the protein completely inhibit the kinase activity of CDK2 in vitro. Thus CAP20 represents a new negative regulatory subunit that inhibits the activity of CDK2/cyclin complexes in mammalian cells.
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721
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Prasad R, Gu Y, Alder H, Nakamura T, Canaani O, Saito H, Huebner K, Gale RP, Nowell PC, Kuriyama K. Cloning of the ALL-1 fusion partner, the AF-6 gene, involved in acute myeloid leukemias with the t(6;11) chromosome translocation. Cancer Res 1993; 53:5624-8. [PMID: 8242616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Reciprocal chromosome translocations involving 11q23 are frequently associated with acute leukemias, with the t(4;11) translocation predominating among acute lymphoblastic leukemias, and the t(9;11), t(11;19) and t(6;11) translocations most common among acute myeloid leukemias. In each of these translocations the ALL-1 gene, located at 11q23 and constituting the human homologue of Drosophila trithorax, fuses to a specific gene on the partner chromosome to produce a chimeric protein. Here we report the cloning and the characterization of the partner gene from chromosome 6 (AF-6). AF-6 is expressed in a variety of cell types and encodes a protein of 1612 amino acids. The protein contains short stretches rich in prolines, charged amino acids, serines, or glutamines. In addition, the AF-6 protein contains the GLGF motif shared with several proteins of vertebrates and invertebrates thought to be involved in signal transduction at special cell-cell junctions.
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722
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Kogire M, Inoue K, Gu Y, Uchida K, Imamura M. Chronic effects of camostate on growth and endocrine function of the pancreas in streptozotocin-induced diabetic rats. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 1993; 204:201-5. [PMID: 8415777 DOI: 10.3181/00379727-204-43653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Chronic feeding of normal rats with camostate, a synthetic trypsin inhibitor, stimulates the growth of the pancreas chiefly by increasing cholecystokinin release. We examined the effects of camostate on the growth and the endocrine function of the pancreas in streptozotocin-induced diabetic rats. The pancreatic weight of the diabetic rats given camostate (200 mg/kg/day) by oral gavage for 14 days was significantly elevated by 120% over that of diabetic rats not given camostate, and was comparable to that in the nondiabetic rats given camostate. The total pancreatic contents of DNA, RNA, and protein in diabetic rats given camostate were also significantly higher than those in diabetic rats not given camostate, and did not differ from those observed in nondiabetic rats given camostate. The pancreatic growth seen in diabetic rats treated with camostate was associated with moderate hyperplasia and pronounced hypertrophy. By contrast, treatment with camostate did not improve hyperglycemia, hypoinsulinemia, or low pancreatic content of insulin seen in diabetic rats. These findings demonstrate a marked growth of the pancreas in diabetic rats stimulated by camostate, and suggest that camostate-induced pancreatic growth is not affected by the reduced level of the endogenous insulin. The present study also indicates that camostate has no beneficial effects on the function of residual B cells, failing to improve diabetes.
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723
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Zhu YC, Chen H, Gu Y, Miao QY, Oki T, Fukuda N, Iuchi A, Tabata T, Ito S. Assessment of left ventricular diastolic function and potential by quantitative analysis of left ventricular filling curves in patients with atrial fibrillation. A new algorithm for Doppler echocardiographic study. JAPANESE HEART JOURNAL 1993; 34:579-90. [PMID: 8301844 DOI: 10.1536/ihj.34.579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To evaluate left ventricular (LV) diastolic function and potential, LV filling curves for 18 patients with atrial fibrillation (Af) were constructed and their positions and appearance were evaluated quantitatively by analysis of 95% maximal filling volume points and maximal curvature alteration points. The LV filling curves of group A (Af only) lay left superiorly, while those of group B (impaired LV diastolic function) were situated right inferiorly, all bending steeply. The LV filling curves of group C (mitral stenosis) bent slightly. The lowest normal filling volume points and compensation areas were calculated to evaluate LV diastolic function and were demonstrated to be very different in groups A and B. The lowest normal filling volume points of group C were similar to those of group A, but compensation areas were smaller, indicating a lower LV diastolic potential. It is concluded that the 95% maximal filling volume point, maximal curvature alteration point, lowest normal filling volume point and compensation area are effective indices for evaluating not only LV diastolic function but also the diastolic potential.
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724
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Gu Y, Gonzalez MF, Chin DY, Deutsch JA. Expression of c-fos in brain subcortical structures in response to nauseant lithium chloride and osmotic pressure in rats. Neurosci Lett 1993; 157:49-52. [PMID: 8233031 DOI: 10.1016/0304-3940(93)90640-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Immunohistochemistry was used to map c-fos expression in rats to investigate the neural substrates that mediate the emetic action of lithium chloride and the effect of osmotic pressure. Solutions of 3% lithium chloride or 4.14% saline, isotonic to each other, as well as 0.65% lithium chloride or 0.9% saline, also isotonic to each other, were administered intraperitoneally (3 ml/kg) in rats. Both lithium chloride and osmotic pressure enhanced c-fos expression in the nuclei of the solitary tract, the paraventricular nuclei and supraoptic nuclei of the hypothalamus, and in the amygdala. This suggests that these brain structures might be the sites where the autonomic, neuroendocrine and behavioral responses elicited by lithium chloride and osmotic pressure are integrated.
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725
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Philipp MT, Aydintug MK, Bohm RP, Cogswell FB, Dennis VA, Lanners HN, Lowrie RC, Roberts ED, Conway MD, Karaçorlu M, Peyman GA, Gubler DJ, Johnson BJ, Piesman J, Gu Y. Early and early disseminated phases of Lyme disease in the rhesus monkey: a model for infection in humans. Infect Immun 1993; 61:3047-59. [PMID: 8514412 PMCID: PMC280958 DOI: 10.1128/iai.61.7.3047-3059.1993] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We demonstrate that Borrelia burgdorferi infection in the rhesus monkey mimics the early and early disseminated phases of human Lyme disease. Clinical, bacteriological, immunological, and pathological signs of infection were investigated during 13 weeks after inoculation of the spirochete. Three animals were given B. burgdorferi (strain JD1) by needle inoculations, six animals were exposed to the bite of B. burgdorferi-infected Ixodes dammini ticks, and three animals were uninfected controls. B. burgdorferi could be recovered from all animals that were given the spirochete. Bacteria were detectable until week 6 postinoculation (p.i.) in blood, until week 8 p.i. in skin biopsies, and at 10 weeks p.i. in the conjunctiva of one of two animals which developed conjunctivitis. Erythema migrans (EM) appeared in one of the three animals infected by needle inoculation and in five of the six animals infected by ticks. Deep dermal perivascular lymphocytic infiltrations (characteristic of human EM) were observed in all animals showing EM clinically. Both EM and conjunctivitis were documented concomitantly with the presence of the spirochete. Lethargy, splenomegaly, and cerebrospinal fluid pleocytosis were also noted in some animals, but the direct connection of these signs with the infection was not shown. The appearance rate of immunoglobulin M and immunoglobulin G antibodies to B. burgdorferi, as well as the antigen spectra recognized, were remarkably similar to those seen in humans. Serum antibodies from infected animals were able to kill B. burgdorferi in vitro in the presence of rhesus complement. The rhesus monkey model appears to be useful for the investigation of the immunology and pathogenesis of Lyme disease and for the development of immunoprophylactic, diagnostic, and chemotherapeutic protocols.
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